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Hefner S, Horstmann R, Kloth S, Vogel M. Quantitative Understanding of Liquid Dynamics at Interfaces from a Free-Energy Landscape Perspective. PHYSICAL REVIEW LETTERS 2024; 133:106201. [PMID: 39303258 DOI: 10.1103/physrevlett.133.106201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 05/10/2024] [Accepted: 07/24/2024] [Indexed: 09/22/2024]
Abstract
On the basis of molecular dynamics simulations of water and ethanol in nanopores, we devise a methodology to determine the free-energy landscape (FEL) imposed by an interface on an adjoining liquid directly from the particle trajectories. The methodology merely uses the statistical mechanical relation between occupancy and energy and, hence, is particularly suitable in complex situations, e.g., for disordered or rough atomistic interfaces and molecular liquids, as encountered in many biological, geological, and technological situations. Moreover, we show that the thus-obtained FEL enables a quantitative understanding of interface effects on liquid dynamics. Specifically, by determining the local minima and barriers of the FEL and using an Arrhenius-like relation, we reproduce the very strong spatial variation of the structural relaxation time of water and ethanol across nanopores over a broad temperature range. We anticipate that the proposed FEL approach is transferable to various other liquids and interfaces.
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2
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Xu Z, Liu Y, Xin Q, Dai J, Yu J, Cheng L, Liu YT, Ding B. Ceramic Meta-Aerogel with Thermal Superinsulation up to 1700 °C Constructed by Self-Crosslinked Nanofibrous Network via Reaction Electrospinning. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2401299. [PMID: 38837520 DOI: 10.1002/adma.202401299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 05/08/2024] [Indexed: 06/07/2024]
Abstract
Thermal insulation under extreme conditions requires the materials to be capable of withstanding complex thermo-mechanical stress, significant gradient temperature transition, and high-frequency thermal shock. The excellent structural and functional properties of ceramic aerogels make them attractive for thermal insulation. However, in extremely high-temperature environments (above 1500 °C), they typically exhibit limited insulation capacity and thermo-mechanical stability, which may lead to catastrophic accidents, and this problem is never effectively addressed. Here, a novel ceramic meta-aerogel constructed from a crosslinked nanofiber network using a reaction electrospinning strategy, which ensures excellent thermo-mechanical stability and superinsulation under extreme conditions, is designed. The ceramic meta-aerogel has an ultralow thermal conductivity of 0.027 W m-1 k-1, and the cold surface temperature is only 303 °C in a 1700 °C high-temperature environment. After undergoing a significant gradient temperature transition from liquid nitrogen to 1700 °C flame burning, the ceramic meta-aerogel can still withstand thousands of shears, flexures, compressions, and other complex forms of mechanical action without structural collapse. This work provides a new insight for developing ceramic aerogels that can be used for a long period in extremely high-temperature environments.
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Affiliation(s)
- Zhen Xu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Yiming Liu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Qi Xin
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Jin Dai
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Jianyong Yu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Longdi Cheng
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Yi-Tao Liu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
| | - Bin Ding
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Innovation Center for Textile Science and Tehnology, Donghua University, Shanghai, 201620, China
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3
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Li X, Fang H, Sankaewtong K, Li M, Chen Y, Huang J, Ni R, Tanaka H, Tan P. Phase Reentrances and Solid Deformations in Confined Colloidal Crystals. PHYSICAL REVIEW LETTERS 2024; 132:018202. [PMID: 38242650 DOI: 10.1103/physrevlett.132.018202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/15/2023] [Accepted: 12/18/2023] [Indexed: 01/21/2024]
Abstract
A simple geometric constraint often leads to novel, complex crystalline phases distinct from the bulk. Using thin-film charge colloidal crystals, a model system with tunable interactions, we study the effects of geometric constraints. Through a combination of experiments and simulations, we systematically explore phase reentrances and solid deformation modes concerning geometrical confinement strength, identifying two distinct categories of phase reentrances below a characteristic layer number, N_{c}: one for bcc bulk-stable and another for fcc bulk-stable systems. We further verify that the dominant thermodynamic origin is the nonmonotonic dependence of solids' free energy on the degree of spatial confinement. Moreover, we discover transitions in solid deformation modes between interface-energy and bulk-energy dominance: below a specific layer number, N_{k}, geometric constraints generate unique soft deformation modes adaptive to confinement. These findings on the N-dependent thermodynamic and kinetic behaviors offer fresh insights into understanding and manipulating thin-film crystal structures.
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Affiliation(s)
- Xiaoxia Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Huang Fang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Krongtum Sankaewtong
- Chemical Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore
| | - Minhuan Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Yanshuang Chen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Jiping Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Ran Ni
- Chemical Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
- Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Peng Tan
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
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4
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Xu Z, Liu H, Wu F, Cheng L, Yu J, Liu YT, Ding B. Inhibited Grain Growth Through Phase Transition Modulation Enables Excellent Mechanical Properties in Oxide Ceramic Nanofibers up to 1700 °C. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2305336. [PMID: 37611152 DOI: 10.1002/adma.202305336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/22/2023] [Indexed: 08/25/2023]
Abstract
Oxide ceramics are widely used as thermal protection materials due to their excellent structural properties and earth abundance. However, in extremely high-temperature environments (above 1500 °C), the explosive growth of grain size causes irreversible damage to the microstructure of oxide ceramics, thus exhibiting poor thermomechanical stability. This problem, which may lead to catastrophic accidents, remains a great challenge for oxide ceramic materials. Here, a novel strategy of phase transition modulation is proposed to control the grain growth at high temperatures in oxide ceramic nanofibers, realizing effective regulation of the crystalline forms as well as the size uniformity of primary grains, and thus suppressing the malignant growth of the grains. The resulting oxide ceramic nanofibers have excellent mechanical strength and flexibility, delivering an average tensile strength as high as 1.02 GPa after being exposed to 1700 °C for 30 min, and can withstand thousands of flexural cycles without obvious damage. This work may provide new insight into the development of advanced oxide ceramic materials that can serve in extremely high-temperature environments with long-term durability.
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Affiliation(s)
- Zhen Xu
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Hualei Liu
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Fan Wu
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Longdi Cheng
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Jianyong Yu
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Yi-Tao Liu
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Bin Ding
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai, 201620, China
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5
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Li YW, Yao Y, Ciamarra MP. Local Plastic Response and Slow Heterogeneous Dynamics of Supercooled Liquids. PHYSICAL REVIEW LETTERS 2022; 128:258001. [PMID: 35802437 DOI: 10.1103/physrevlett.128.258001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/26/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate, via numerical simulations, that the relaxation dynamics of supercooled liquids correlates well with a plastic length scale measuring a particle's response to impulsive localized perturbations and weakly to measures of local elasticity. We find that the particle averaged plastic length scale vanishes linearly in temperature and controls the super-Arrhenius temperature dependence of the relaxation time. Furthermore, we show that the plastic length scale of individual particles correlates with their typical displacement at the relaxation time. In contrast, the local elastic response only correlates with the dynamics on the vibrational timescale.
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Affiliation(s)
- Yan-Wei Li
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Yugui Yao
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Massimo Pica Ciamarra
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore, CNR-SPIN, Dipartimento di Scienze Fisiche, Università di Napoli Federico II, I-80126, Napoli, Italy and CNRS@CREATE LTD, 1 Create Way, No. 08-01 CREATE Tower, Singapore 138602, Singapore
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6
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Horstmann R, Hecht L, Kloth S, Vogel M. Structural and Dynamical Properties of Liquids in Confinements: A Review of Molecular Dynamics Simulation Studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6506-6522. [PMID: 35580166 DOI: 10.1021/acs.langmuir.2c00521] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular dynamics (MD) simulations are a powerful tool for detailed studies of altered properties of liquids in confinement, in particular, of changed structures and dynamics. They allow, on one hand, for perfect control and systematic variation of the geometries and interactions inherent in confinement situations and, on the other hand, for type-selective and position-resolved analyses of a huge variety of structural and dynamical parameters. Here, we review MD simulation studies on various types of liquids and confinements. The main focus is confined aqueous systems, but also ionic liquids and polymer and silica melts are discussed. Results for confinements featuring different interactions, sizes, shapes, and rigidity will be presented. Special attention will be given to situations in which the confined liquid and the confining matrix consist of the same type of particles and, hence, disparate liquid-matrix interactions are absent. Findings for the magnitude and the range of wall effects on molecular positions and orientations and on molecular dynamics, including vibrational motion and structural relaxation, are reviewed. Moreover, their dependence on the parameters of the confinement and their relevance to theoretical approaches to the glass transition are addressed.
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Affiliation(s)
- Robin Horstmann
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Lukas Hecht
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Sebastian Kloth
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
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7
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Williams I, Oğuz EC, Löwen H, Poon WCK, Royall CP. The rheology of confined colloidal hard disks. J Chem Phys 2022; 156:184902. [DOI: 10.1063/5.0087444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Colloids may be treated as “big atoms” so that they are good models for atomic and molecular systems. Colloidal hard disks are, therefore, good models for 2d materials, and although their phase behavior is well characterized, rheology has received relatively little attention. Here, we exploit a novel, particle-resolved, experimental setup and complementary computer simulations to measure the shear rheology of quasi-hard-disk colloids in extreme confinement. In particular, we confine quasi-2d hard disks in a circular “corral” comprised of 27 particles held in optical traps. Confinement and shear suppress hexagonal ordering that would occur in the bulk and create a layered fluid. We measure the rheology of our system by balancing drag and driving forces on each layer. Given the extreme confinement, it is remarkable that our system exhibits rheological behavior very similar to unconfined 2d and 3d hard particle systems, characterized by a dynamic yield stress and shear-thinning of comparable magnitude. By quantifying particle motion perpendicular to shear, we show that particles become more tightly confined to their layers with no concomitant increase in density upon increasing the shear rate. Shear thinning is, therefore, a consequence of a reduction in dissipation due to weakening in interactions between layers as the shear rate increases. We reproduce our experiments with Brownian dynamics simulations with Hydrodynamic Interactions (HI) included at the level of the Rotne–Prager tensor. That the inclusion of HI is necessary to reproduce our experiments is evidence of their importance in transmission of momentum through the system.
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Affiliation(s)
- Ian Williams
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
- H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, United Kingdom
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Erdal C. Oğuz
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv 6997801, Israel
- The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
- School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hartmut Löwen
- Institut für Theoretische Physik II, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Wilson C. K. Poon
- SUPA and School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - C. Patrick Royall
- H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, United Kingdom
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
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8
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Song Z, Rodríguez-Tinoco C, Mathew A, Napolitano S. Fast equilibration mechanisms in disordered materials mediated by slow liquid dynamics. SCIENCE ADVANCES 2022; 8:eabm7154. [PMID: 35427165 PMCID: PMC9012462 DOI: 10.1126/sciadv.abm7154] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
The rate at which a nonequilibrium system decreases its free energy is commonly ascribed to molecular relaxation processes, arising from spontaneous rearrangements at the microscopic scale. While equilibration of liquids usually requires density fluctuations at time scales quickly diverging upon cooling, growing experimental evidence indicates the presence of a different, alternative pathway of weaker temperature dependence. Such equilibration processes exhibit a temperature-invariant activation energy, on the order of 100 kJ mol-1. Here, we identify the underlying molecular process responsible for this class of Arrhenius equilibration mechanisms with a slow mode (SAP), universally observed in the liquid dynamics of thin films. The SAP, which we show is intimately connected to high-temperature flow, can efficiently drive melts and glasses toward more stable, less energetic states. Our results show that measurements of liquid dynamics can be used to predict the equilibration rate in the glassy state.
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9
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Yimam DT, Kooi BJ. Thickness-Dependent Crystallization of Ultrathin Antimony Thin Films for Monatomic Multilevel Reflectance and Phase Change Memory Designs. ACS APPLIED MATERIALS & INTERFACES 2022; 14:13593-13600. [PMID: 35266381 PMCID: PMC8949766 DOI: 10.1021/acsami.1c23974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Phase change materials, with more than one reflectance and resistance states, have been a subject of interest in the fields of phase change memories and nanophotonics. Although most current research focuses on rather complex phase change alloys, e.g., Ge2Sb2Te5, recently, monatomic antimony thin films have aroused a lot of interest. One prominent attractive feature is its simplicity, giving fewer reliability issues like segregation and phase separation. However, phase transformation and crystallization properties of ultrathin Sb thin films must be understood to fully incorporate them into future memory and nanophotonics devices. Here, we studied the thickness-dependent crystallization behavior of pulsed laser-deposited ultrathin Sb thin films by employing dynamic ellipsometry. We show that the crystallization temperature and phase transformation speed of as-deposited amorphous Sb thin films are thickness-dependent and can be precisely tuned by controlling the film thickness. Thus, crystallization temperature tuning by thickness can be applied to future memory and nanophotonic devices. As a proof of principle, we designed a heterostructure device with three Sb layers of varying thicknesses with distinct crystallization temperatures. Measurements and simulation results show that it is possible to address these layers individually and produce distinct and multiple reflectance profiles in a single device. In addition, we show that the immiscible nature of Sb and GaSb could open up possible heterostructure device designs with high stability after melt-quench and increased crystallization temperature. Our results demonstrate that the thickness-dependent phase transformation and crystallization dynamics of ultrathin Sb thin films have attractive features for future memory and nanophotonic devices.
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10
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Improving Mechanical Properties of a Forged High-Manganese Alloy by Regulating Carbon Content and Carbide Precipitation. METALS 2022. [DOI: 10.3390/met12030473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The effect of different heat treatment processes (as-cast, annealing, forging, and annealing after forging) on the microstructure transition and mechanical property evolution of Fe50Mn30Co10Cr10 alloys with different carbon contents (0, 0.2, 0.5 wt.%) was investigated, and a potential strengthening–toughening mechanism was revealed. With 0.5 wt.% carbon added, the interstitial carbon atoms provided a great deal of strength and the highest hardness was obtained. Meanwhile, the high carbon content generated a large amount of stacking fault energy and inhibited the transition of a face-centered cubic (FCC) to a hexagonal close-packed phase (HCP); as such, the TRIP and TWIP effects were induced during deformation and a favorable ductility with the largest elongation to fracture (of 141%) was achieved. The forged-annealed specimen with 0.2 wt.% carbon obtained favorable comprehensive mechanical properties, with an ultimate tensile strength of 795 MPa and an elongation of 104%. After forging, the grains were refined and several dislocations were generated; as such, the yield strength was greatly improved. With subsequent annealing, a good phase distribution of FCC and HCP was achieved, inducing the TRIP and TWIP effects during deformation and producing favorable ductility.
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11
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Effects of Heat Treatment on the Microstructure and Mechanical Properties of a Novel H-Grade Sucker Rod Steel. METALS 2022. [DOI: 10.3390/met12020294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The sucker rod is an extremely important equipment in oil exploitation, but with the deepening and harsh environment of the petroleum well, higher requirements are put forward for the strength and corrosion resistance of the sucker rod. The most commonly used steel for H grade sucker rods is 4330 steel. However, it has characteristics such as high cost and relatively low sulfide stress cracking resistance. Thus, a novel sucker rod steel with a composition of 0.2 wt.% Cu and 1.2 wt.% Ni was designed. Normalizing + tempering (NT) and quenching + tempering (QT) heat treatment were optimized to render the mechanical properties of the novel sucker rod steel to reach the H grade. Additionally, effects of heat treatment on the microstructural evolution and mechanical properties of the novel sucker rod steel were investigated by optical microscope, scanning electron microscope and mechanical property tests. The results showed that the microstructure is tempered sorbite and the mechanical properties reach H grade after NT and QT. Specifically, the tensile strength, yield strength, elongation and impact toughness of NT/QT samples reached 1010.58/1124.37 MPa, 875.93/1042.63 MPa, 15.66/11.59% and ~77.48/~111.69 J/cm2, respectively. Furthermore, the finer and more dispersed carbides were observed in the QT sample, which means that the QT sample had better strength and toughness.
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12
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Köster R, Vogel M. Slow liquid dynamics near solid surfaces: Insights from site-resolved studies of ionic liquids in silica confinement. J Chem Phys 2022; 156:074501. [DOI: 10.1063/5.0079722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Michael Vogel
- Institute of Condensed Matter Physics, TU Darmstadt, Germany
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13
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Luo C, Huang M, Sun X, Wei N, Shi H, Li H, Lin M, Sun J. Super-Strong, Nonswellable, and Biocompatible Hydrogels Inspired by Human Tendons. ACS APPLIED MATERIALS & INTERFACES 2022; 14:2638-2649. [PMID: 35045604 DOI: 10.1021/acsami.1c23102] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fabricating artificial materials that mimic the structures and properties of tendons is of great significance. Possessing a tensile stress of approximately 10.0 MPa and a water content of around 60%, human tendons exhibit excellent mechanical properties to support daily functions. In contrast to tendons, most synthetic hydrogels with similar water content typically exclude qualified strength, swelling resistance, and biocompatibility. Herein, a facile strategy based on poly(vinyl alcohol) (PVA) and tannic acid (TA) is demonstrated to tackle this problem via a combination of sequential steps including freezing-thawing PVA aqueous solutions to form crystalline regions, prestretching and air drying in confined conditions to induce anisotropic structures, soaking in TA solutions to form multiple hydrogen bondings between PVA and TA, and finally dialyzing against water for the removal of residual TA molecules and the rearrangements and homogenization of multiple hydrogen bonds. The obtained PVA hydrogels possess hierarchically anisotropic structures, where the alignment of PVA bundles promotes high modulus, while the hydrogen bonding between PVA and TA endows them with an energy dissipation mechanism. Benefitting from the synergy of material composition and structural engineering, the obtained hydrogel displays super-strong mechanics (a tensile stress of 19.3 MPa and a toughness of 32.1 MJ/m3), outperforming most tough hydrogels. Remarkably, this hydrogel demonstrates excellent swelling resistance. It barely expands after immersion in deionized water, phosphate-buffered saline (PBS), and SBF aqueous solutions for 7 days with the strength and volume nearly the same as their initial values. All of the features, combined with excellent cytocompatibility, make it an ideal material for biotechnological and biomedical applications.
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Affiliation(s)
- Chunhui Luo
- College of Chemistry and Chemical Engineering, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
- Key Laboratory of Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
- Ningxia Key Laboratory of Solar Chemical Conversion Technology, North Minzu University, Yinchuan 750021, P. R. China
| | - Min Huang
- College of Chemistry and Chemical Engineering, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
| | - Xinxin Sun
- College of Chemistry and Chemical Engineering, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
| | - Ning Wei
- College of Chemistry and Chemical Engineering, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
| | - Huan Shi
- College of Chemistry and Chemical Engineering, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
| | - Hui Li
- College of Chemistry and Chemical Engineering, North Minzu University, Yinchuan, Ningxia 750021, P. R. China
| | - Min Lin
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Jing Sun
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
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14
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Chun DJ, Oh Y, Sung BJ. Translation-rotation decoupling of tracers reflects medium-range crystalline order in two-dimensional colloid glasses. Phys Rev E 2021; 104:054615. [PMID: 34942845 DOI: 10.1103/physreve.104.054615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/17/2021] [Indexed: 11/07/2022]
Abstract
The dynamic heterogeneity and the translation-rotation decoupling are the dynamic signatures of glasses and supercooled liquids. Whether and how the dynamic heterogeneity would relate to the local structure of glasses has been a puzzle for decades. In this work we perform molecular dynamics simulations for tracers in both two-dimensional polydisperse colloids (2DPC) and two-dimensional binary colloids (2DBC). In 2DPC glasses, hexatic local structures develop at low enough temperatures and grow quickly along with the dynamic correlation length of the 2DPC, which is well known as the medium-range crystalline order (MRCO). In 2DBC glasses, on the other hand, any explicit local structure has not been reported to grow significantly with the dynamic correlation length at low temperatures. We introduce two different types of tracers into colloidal systems: A diamond tracer that resembles the MRCO of 2DPC glasses and a square tracer that is dissimilar to any local structure of glasses. The translation-rotation decoupling of the diamond tracer in 2DPC glasses is much more significant than that of the square tracer in the same 2DPC glasses. On the other hand, such a tracer shape-dependence of the decoupling is not observed in 2DBC glasses where the local hexatic structure does not develop significantly. We introduce a shape-dependency parameter of the decoupling and find that the shape-dependency parameter grows along with the dynamic correlation length in 2DPC glasses but not in 2DBC glasses. This illustrates that the dynamic heterogeneity and the translation-rotation decoupling of tracers could reveal the local structure that develops in glasses.
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Affiliation(s)
- Dong Jae Chun
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Younghoon Oh
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Bong June Sung
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
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15
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Zhang R, Troya D, Madsen LA. Prolonged Association between Water Molecules under Hydrophobic Nanoconfinement. J Phys Chem B 2021; 125:13767-13777. [PMID: 34898212 DOI: 10.1021/acs.jpcb.1c06810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present an investigation of the dynamics of water confined among rigid carbon rods and between parallel graphene sheets with molecular dynamics simulations. Diffusion coefficients, activation energy of diffusion, and residence-time correlation functions as a function of confinement geometry reveal a retardation of water dynamics under hydrophobic confinement compared to bulk water. In fact, water under various confinements possesses longer associations with its neighbors and exhibits diffusion dynamics characteristic of a lower temperature. Analysis of the residence-time correlation functions reveals long and short residence times, which we relate to the diffusion coefficient and activation energy of diffusion, respectively. Additional investigations reveal how the level of confining surface hydrophobicity affects water dynamics, further broadening our understanding of water diffusion inside diverse media. Overall, this study sheds light on the physical origin of retarded water dynamics under hydrophobic confinement and the close relationship between residence times and diffusion behavior.
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Affiliation(s)
- Rui Zhang
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Diego Troya
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Louis A Madsen
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
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16
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Zhang Y, Liu S, Yan J, Zhang X, Xia S, Zhao Y, Yu J, Ding B. Superior Flexibility in Oxide Ceramic Crystal Nanofibers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2105011. [PMID: 34532907 DOI: 10.1002/adma.202105011] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/21/2021] [Indexed: 05/27/2023]
Abstract
Oxide crystal ceramics are commonly hard and brittle, when they are bent they typically fracture. Such mechanical response limits the use of these materials in emerging fields like wearable electronics. Here, a polymer-induced assembly strategy is reported to construct orderly assembled TiO2 crystals into continuous nanofibers that are stretchable, bendable, and even knottable. Ball-milling the spinning sol and curved-drafting the electrospun nanofibers significantly improve the molecular structural order and reduce pore defects in the precursor nanofibers. Using this method, continuous TiO2 nanofibers, in which orderly assembled TiO2 nanocrystals (brick) are connected by twin grain boundaries or an amorphous region (mortar), are formed after sintering. Mechanical measurements and finite element analysis simulation indicate that the dislocation slip of "bricks" and the elastic deformation of "mortar" render the nanofibers with a small bending rigidity of ≈22 mN and a small elastic modulus of ≈20.8 Gpa, thus displaying properties associated with both soft and hard matter. More importantly, the reported approach can be easily extended to synthesize a wide range of soft, yet tough ceramic membranes, such as ZrO2 and SiO2 .
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Affiliation(s)
- Yuanyuan Zhang
- Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Shujie Liu
- Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Jianhua Yan
- Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, 201620, China
| | - Xiaohua Zhang
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China
| | - Shuhui Xia
- Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Yun Zhao
- Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Jianyong Yu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, 201620, China
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China
| | - Bin Ding
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, 201620, China
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China
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17
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Gao Q, Ai J, Tang S, Li M, Chen Y, Huang J, Tong H, Xu L, Xu L, Tanaka H, Tan P. Fast crystal growth at ultra-low temperatures. NATURE MATERIALS 2021; 20:1431-1439. [PMID: 33958770 DOI: 10.1038/s41563-021-00993-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
It is believed that the slow liquid diffusion and geometric frustration brought by a rapid, deep quench inhibit fast crystallization and promote vitrification. Here we report fast crystal growth in charged colloidal systems under deep supercooling, where liquid diffusion is extremely low. By combining experiments and simulations, we show that this process occurs via wall-induced barrierless ordering consisting of two coupled steps: the step-like advancement of the rough interface that disintegrates frustration, followed by defect repairing inside the newly formed solid phase. The former is a diffusionless collective process, whereas the latter controls crystal quality. We further show that the intrinsic mechanical instability of a disordered glassy state subject to the crystal growth front allows for domino-like fast crystal growth even at ultra-low temperatures. These findings contribute to a deeper understanding of fast crystal growth and may be useful for applications related to vitrification prevention and crystal-quality control.
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Affiliation(s)
- Qiong Gao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Jingdong Ai
- International Centre for Quantum Materials and School of Physics, Peking University, Beijing, China
| | - Shixiang Tang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Minhuan Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Yanshuang Chen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Jiping Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Hua Tong
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Tokyo, Japan
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
- Department of Physics, University of Science and Technology of China, Hefei, China
| | - Lei Xu
- Department of Physics, The Chinese University of Hong Kong, Hong Kong, China
| | - Limei Xu
- International Centre for Quantum Materials and School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Tokyo, Japan.
- Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan.
| | - Peng Tan
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
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18
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Pham KH, Thuy Giap TT. The liquid-amorphous phase transition, slow dynamics and dynamical heterogeneity for bulk iron: a molecular dynamics simulation. RSC Adv 2021; 11:32435-32445. [PMID: 35495543 PMCID: PMC9042048 DOI: 10.1039/d1ra06394d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/25/2021] [Indexed: 01/22/2023] Open
Abstract
Based on molecular dynamics (MD) simulations, we investigate the liquid-amorphous phase transition, slow dynamic and dynamical heterogeneity (DH) for bulk iron in temperatures ranging 300-2300 K. The structure of obtained models is explored through the pair radial distribution function (PRDF) and simplex statistics. It was shown that the splitting of a PRDF second peak appears when the liquid transforms to an amorphous solid. This feature is originated from the transformation of simplexes from strongly-to weakly-distorted tetrahedron type. Further, we reveal that the diffusivity in the liquid is realized through the local density fluctuations (LDF) which are strongly correlated with each other. The diffusion coefficient is found to be a product of the rate of LDF act and mean square displacement of particles per LDF act. The later quantity mainly contributes to the slow dynamics and DH in the liquid. We found that the mobile atom clusters move during relaxation time, but mobile atoms do not tend to leave their cluster. Our work is expected to contribute a pathway to determine the liquid-amorphous phase transition and DH heterogeneity of bulk metal.
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Affiliation(s)
- Kien Huu Pham
- Department of Physics, Thainguyen University of Education No. 20 Luong Ngoc Quyen Thainguyen Vietnam
| | - Trang Thi Thuy Giap
- Department of Physics, Thainguyen University of Education No. 20 Luong Ngoc Quyen Thainguyen Vietnam
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19
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Nieto Simavilla D, Abate AA, Liu J, Geerts YH, Losada-Peréz P, Napolitano S. 1D-Confinement Inhibits the Anomaly in Secondary Relaxation of a Fluorinated Polymer. ACS Macro Lett 2021; 10:649-653. [PMID: 35570757 DOI: 10.1021/acsmacrolett.1c00220] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present an experimental study of the dynamics of a well-pronounced secondary relaxation observed in bulk and ultrathin films of the fluorinated copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). In proximity to the glass transition, an anomalous phenomenon is observed: the β-relaxation slows down upon heating. Measurements as a function of the film thickness show that this exceptional behavior gradually vanishes upon confinement at the nanoscale level. Regardless of sample size, the relaxation dynamics could be described in terms of the Minimal Model via an asymmetric double well potential. Supported by a structural investigation of surfaces and interfaces, our results reveal that the presence of adsorbing walls induces an increase in glass transition temperature, which counterbalances the asymmetry in the double well potential responsible for molecular motion.
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Affiliation(s)
- David Nieto Simavilla
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Université libre de Bruxelles (ULB), Bruxelles 1050, Belgium
| | - Anabella A Abate
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Université libre de Bruxelles (ULB), Bruxelles 1050, Belgium
| | - Jie Liu
- Laboratoire de Chimie des Polyméres, Université Libre de Bruxelles (ULB), 1050 Bruxelles, Belgium
| | - Yves H Geerts
- Laboratoire de Chimie des Polyméres, Université Libre de Bruxelles (ULB), 1050 Bruxelles, Belgium.,International Solvay Institutes of Physics and Chemistry, ULB - Campus Plaine - CP 231, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - Patricia Losada-Peréz
- Experimental Soft Matter and Thermal Physics (EST), Université Libre de Bruxelles (ULB), Bruxelles 1050, Belgium
| | - Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Université libre de Bruxelles (ULB), Bruxelles 1050, Belgium
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20
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Singh J, Mustakim M, Anil Kumar AV. Super-Arrhenius diffusion in a binary colloidal mixture at low volume fraction: an effect of depletion interaction due to an asymmetric barrier. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:125101. [PMID: 33463528 DOI: 10.1088/1361-648x/abd428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report results from the molecular dynamics simulations of a binary colloidal mixture subjected to an external potential barrier along one of the spatial directions at low volume fraction, ϕ = 0.2. The variations in the asymmetry of the external potential barrier do not change the dynamics of the smaller particles, showing Arrhenius diffusion. However, the dynamics of the larger particles shows a crossover from sub-Arrhenius to super-Arrhenius diffusion with the asymmetry in the external potential at the low temperatures and low volume fraction. Super-Arrhenius diffusion is generally observed in the high density systems where the transient cages are present due to dense packing, e.g., supercooled liquids, jammed systems, diffusion through porous membranes, dynamics within the cellular environment, etc. This model can be applied to study the molecular transport across cell membranes, nano-, and micro-channels which are characterized by spatially asymmetric potentials.
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Affiliation(s)
- Jalim Singh
- School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni, Bhubaneswar 752050, India
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21
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Kooi BJ, Wuttig M. Chalcogenides by Design: Functionality through Metavalent Bonding and Confinement. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1908302. [PMID: 32243014 DOI: 10.1002/adma.201908302] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/03/2020] [Accepted: 02/03/2020] [Indexed: 05/27/2023]
Abstract
A unified picture of different application areas for incipient metals is presented. This unconventional material class includes several main-group chalcogenides, such as GeTe, PbTe, Sb2 Te3 , Bi2 Se3 , AgSbTe2 and Ge2 Sb2 Te5 . These compounds and related materials show a unique portfolio of physical properties. A novel map is discussed, which helps to explain these properties and separates the different fundamental bonding mechanisms (e.g., ionic, metallic, and covalent). The map also provides evidence for an unconventional, new bonding mechanism, coined metavalent bonding (MVB). Incipient metals, employing this bonding mechanism, also show a special bond breaking mechanism. MVB differs considerably from resonant bonding encountered in benzene or graphite. The concept of MVB is employed to explain the unique properties of materials utilizing it. Then, the link is made from fundamental insights to application-relevant properties, crucial for the use of these materials as thermoelectrics, phase change materials, topological insulators or as active photonic components. The close relationship of the materials' properties and their application potential provides optimization schemes for different applications. Finally, evidence will be presented that for metavalently bonded materials interesting effects arise in reduced dimensions. In particular, the consequences for the crystallization kinetics of thin films and nanoparticles will be discussed in detail.
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Affiliation(s)
- Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747 AG, the Netherlands
| | - Matthias Wuttig
- Institute of Physics IA, RWTH Aachen University, Aachen, 52074, Germany
- JARA-Institute: Energy-Efficient Information Technology (Green IT), Forschungszentrum Jülich GmbH, Jülich, 52428, Germany
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22
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Roberts RC, Marioni N, Palmer JC, Conrad JC. Dynamics of polydisperse hard-spheres under strong confinement. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1728407] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ryan C. Roberts
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Nico Marioni
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Jeremy C. Palmer
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
| | - Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
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23
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Watanabe C, Kobori Y, Yamamoto J, Kinjo M, Yanagisawa M. Quantitative Analysis of Membrane Surface and Small Confinement Effects on Molecular Diffusion. J Phys Chem B 2020; 124:1090-1098. [PMID: 31939302 DOI: 10.1021/acs.jpcb.9b10558] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Molecular behaviors in small liquid droplets (picoliter scale), such as phase transitions and chemical reactions, are essential for the industrial application of small droplets and their use as artificial cells. However, the droplets often differ from those in bulk solutions (milliliter scale). Since the droplet size is much larger than the molecular size, the so-called size effect that draws these differences has attracted attention as a target to be solved. Although the small volume and the membrane surface surrounding the droplet are thought to be the origin of the size effect, there were little attempts to separate and quantify them. To solve the problem, we develop a series of systems for the evaluation. Using these systems, we have evaluated the size effect of concentrated polymer solutions on molecular diffusion by dividing it into small volume and membrane surface contributions. Our results demonstrate that the size effect on the molecular diffusion originates from the long-range interaction with the surface enhanced with decreasing volume. The quantitative size effect revealed by the systems provides novel insights in the biophysical understanding of molecular behaviors in cells and to the regulation and design of micrometer-sized materials.
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Affiliation(s)
- Chiho Watanabe
- Komaba Institute for Science , The University of Tokyo , Komaba 3-8-1 , Meguro , Tokyo 153-8902 , Japan
| | - Yuta Kobori
- Komaba Institute for Science , The University of Tokyo , Komaba 3-8-1 , Meguro , Tokyo 153-8902 , Japan.,Department of Applied Physics , Tokyo University of Agriculture and Technology , Naka-cho 2-24-16 , Koganei , Tokyo 184-8588 , Japan
| | - Johtaro Yamamoto
- Biomedical Research Institute , National Institute of Advanced Industrial Science and Technology (AIST) , Central 6, Higashi 1-1-1 , Tsukuba , Ibaraki 305-8568 , Japan
| | - Masataka Kinjo
- Faculty of Advanced Life Science , Hokkaido University , Kita-21 Nishi-11 Kita-ku , Sapporo , Hokkaido 001-0021 , Japan
| | - Miho Yanagisawa
- Komaba Institute for Science , The University of Tokyo , Komaba 3-8-1 , Meguro , Tokyo 153-8902 , Japan.,Department of Basic Science , The University of Tokyo , Komaba 3-8-1 , Meguro , Tokyo 153-8902 , Japan
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24
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Chandran S, Baschnagel J, Cangialosi D, Fukao K, Glynos E, Janssen LMC, Müller M, Muthukumar M, Steiner U, Xu J, Napolitano S, Reiter G. Processing Pathways Decide Polymer Properties at the Molecular Level. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01195] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | - Jörg Baschnagel
- Institut Charles Sadron, Université de Strasbourg & CNRS, 23 rue du Loess, 67034 Cedex, Strasbourg, France
| | - Daniele Cangialosi
- Centro de Física de Materiales CFM (CSIC-UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastin, Spain
| | - Koji Fukao
- Department of Physics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Emmanouil Glynos
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O.
Box 1385, 711 10 Heraklion, Crete, Greece
| | - Liesbeth M. C. Janssen
- Theory of Polymers and Soft Matter, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August-Universität, Göttingen, Germany
| | - Murugappan Muthukumar
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Ullrich Steiner
- Adolphe Merkle Institute, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Jun Xu
- Advanced Materials Laboratory of Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics, Faculté des Sciences, Université libre de Bruxelles (ULB), CP223, Boulevard du Triomphe, Bruxelles 1050, Belgium
| | - Günter Reiter
- Institute of Physics, University of Freiburg, Freiburg 79104, Germany
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25
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Zhang B, Cheng X. Long-wavelength fluctuations and static correlations in quasi-2D colloidal suspensions. SOFT MATTER 2019; 15:4087-4097. [PMID: 31074481 DOI: 10.1039/c9sm00302a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Dimensionality strongly affects thermal fluctuations and critical dynamics of equilibrium systems. These influences persist in amorphous systems going through the nonequilibrium glass transition. Here, we experimentally study the glass transition of quasi-2D suspensions of spherical and ellipsoidal particles under different degrees of circular confinement. We show that the strength of the long-wavelength fluctuations increases logarithmically with system sizes and displays the signature of the Mermin-Wagner fluctuations. Moreover, using confinement as a tool, we also measure static structural correlations and extract a growing static correlation length in 2D supercooled liquids. Finally, we explore the influence of the Mermin-Wagner fluctuations on the translational and orientational relaxations of 2D ellipsoidal suspensions, which leads to a new interpretation of the two-step glass transition and the orientational glass phase of anisotropic particles. Our study reveals the importance of long-wavelength fluctuations in 2D supercooled liquids and provides new insights into the role of dimensionality in the glass transition.
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Affiliation(s)
- Bo Zhang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
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26
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Link between molecular mobility and order parameter during liquid-liquid transition of a molecular liquid. Proc Natl Acad Sci U S A 2019; 116:7176-7185. [PMID: 30944219 DOI: 10.1073/pnas.1822016116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Liquid-liquid transition (LLT) is the transformation of one liquid to another via first-order phase transition. For example, LLT in a molecular liquid, triphenyl phosphite, is macroscopically the transformation from liquid I in a supercooled state to liquid II in a glassy state. Reflecting the transformation from the liquid to glassy state, the LLT is accompanied by considerable slowing down of overall molecular dynamics, but little is known about how this proceeds at a molecular level coupled with the evolution of the order parameter. We report such information by performing time-resolved simultaneous measurements of dielectric spectroscopy and phase contrast microscopy/Raman spectroscopy by using a dielectric cell with transparent electrodes. We find that the temporal change in molecular mobility crucially depends on whether LLT is nucleation growth type occurring in the metastable state or SD type occurring in the unstable state. Furthermore, our results suggest that the molecular mobility is controlled by the local order parameter: more specifically, the local activation energy of molecular rotation is controlled by the local fraction of locally favored structures formed in the liquid. Our study sheds light on the temporal change in the molecular dynamics during LLT and its link to the order parameter evolution.
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27
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Zhang T, Winey KI, Riggleman RA. Polymer Conformations and Dynamics under Confinement with Two Length Scales. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01779] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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28
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Salinga M, Kersting B, Ronneberger I, Jonnalagadda VP, Vu XT, Le Gallo M, Giannopoulos I, Cojocaru-Mirédin O, Mazzarello R, Sebastian A. Monatomic phase change memory. NATURE MATERIALS 2018; 17:681-685. [PMID: 29915424 DOI: 10.1038/s41563-018-0110-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/16/2018] [Indexed: 05/09/2023]
Abstract
Phase change memory has been developed into a mature technology capable of storing information in a fast and non-volatile way1-3, with potential for neuromorphic computing applications4-6. However, its future impact in electronics depends crucially on how the materials at the core of this technology adapt to the requirements arising from continued scaling towards higher device densities. A common strategy to fine-tune the properties of phase change memory materials, reaching reasonable thermal stability in optical data storage, relies on mixing precise amounts of different dopants, resulting often in quaternary or even more complicated compounds6-8. Here we show how the simplest material imaginable, a single element (in this case, antimony), can become a valid alternative when confined in extremely small volumes. This compositional simplification eliminates problems related to unwanted deviations from the optimized stoichiometry in the switching volume, which become increasingly pressing when devices are aggressively miniaturized9,10. Removing compositional optimization issues may allow one to capitalize on nanosize effects in information storage.
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Affiliation(s)
- Martin Salinga
- IBM Research-Zurich, Rüschlikon, Switzerland.
- RWTH Aachen University, Aachen, Germany.
| | - Benedikt Kersting
- IBM Research-Zurich, Rüschlikon, Switzerland
- RWTH Aachen University, Aachen, Germany
| | - Ider Ronneberger
- IBM Research-Zurich, Rüschlikon, Switzerland
- RWTH Aachen University, Aachen, Germany
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29
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Wang H, Hor JL, Zhang Y, Liu T, Lee D, Fakhraai Z. Dramatic Increase in Polymer Glass Transition Temperature under Extreme Nanoconfinement in Weakly Interacting Nanoparticle Films. ACS NANO 2018; 12:5580-5587. [PMID: 29792676 DOI: 10.1021/acsnano.8b01341] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Properties of polymers in polymer nanocomposites and nanopores have been shown to deviate from their respective bulk properties due to physical confinement as well as polymer-particle interfacial interactions. However, separating the confinement effects from the interfacial effects under extreme nanoconfinement is experimentally challenging. Capillary rise infiltration enables polymer infiltration into nanoparticle (NP) packings, thereby confining polymers within extremely small pores and dramatically increasing the interfacial area, providing a good system to systematically distinguish the role of each effect on polymer properties. In this study, we investigate the effect of spatial confinement on the glass transition temperature ( Tg) of polystyrene (PS) infiltrated into SiO2 NP films. The degree of confinement is tuned by varying the molecular weight of polymers, the size of NPs (diameters between 11 and 100 nm, producing 3-30 nm average pore sizes), and the fill-fraction of PS in the NP films. We show that in these dense NP packings the Tg of confined PS, which interacts weakly with SiO2 NPs, significantly increases with decreasing pore size such that for the two molecular weights of PS studied the Tg increases by up to 50 K in 11 nm NP packings, while Tg is close to the bulk Tg in 100 nm NP packings. Interestingly, as the fill-fraction of PS is decreased, resulting in the accumulation of the polymer in the contacts between nanoparticles, hence an increased specific interfacial area, the Tg further increases relative to the fully filled films by another 5-8 K, indicating the strong role of geometrical confinement as opposed to the interfacial effects on the measured Tg values.
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Affiliation(s)
- Haonan Wang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Jyo Lyn Hor
- Department of Chemical and Biomolecular Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Yue Zhang
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Tianyi Liu
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Zahra Fakhraai
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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30
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Configuration correlation governs slow dynamics of supercooled metallic liquids. Proc Natl Acad Sci U S A 2018; 115:6375-6380. [PMID: 29866833 DOI: 10.1073/pnas.1802300115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The origin of dramatic slowing down of dynamics in metallic glass-forming liquids toward their glass transition temperatures is a fundamental but unresolved issue. Through extensive molecular dynamics simulations, here we show that, contrary to the previous beliefs, it is not local geometrical orderings extracted from instantaneous configurations but the intrinsic correlation between configurations that captures the structural origin governing slow dynamics. More significantly, it is demonstrated by scaling analyses that it is the correlation length extracted from configuration correlation rather than dynamic correlation lengths that is the key to determine the drastic slowdown of supercooled metallic liquids. The key role of the configuration correlation established here sheds important light on the structural origin of the mysterious glass transition and provides an essential piece of the puzzle for the development of a universal theoretical understanding of glass transition in glasses.
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Ingebrigtsen TS, Tanaka H. Structural predictor for nonlinear sheared dynamics in simple glass-forming liquids. Proc Natl Acad Sci U S A 2018; 115:87-92. [PMID: 29247052 PMCID: PMC5776798 DOI: 10.1073/pnas.1711655115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glass-forming liquids subjected to sufficiently strong shear universally exhibit striking nonlinear behavior; for example, a power-law decrease of the viscosity with increasing shear rate. This phenomenon has attracted considerable attention over the years from both fundamental and applicational viewpoints. However, the out-of-equilibrium and nonlinear nature of sheared fluids have made theoretical understanding of this phenomenon very challenging and thus slower to progress. We find here that the structural relaxation time as a function of the two-body excess entropy, calculated for the extensional axis of the shear flow, collapses onto the corresponding equilibrium curve for a wide range of pair potentials ranging from harsh repulsive to soft and finite. This two-body excess entropy collapse provides a powerful approach to predicting the dynamics of nonequilibrium liquids from their equilibrium counterparts. Furthermore, the two-body excess entropy scaling suggests that sheared dynamics is controlled purely by the liquid structure captured in the form of the two-body excess entropy along the extensional direction, shedding light on the perplexing mechanism behind shear thinning.
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Affiliation(s)
- Trond S Ingebrigtsen
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan
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32
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Smith ND, Smith MI. Boundary effects in a quasi-two-dimensional driven granular fluid. Phys Rev E 2017; 96:062910. [PMID: 29347371 DOI: 10.1103/physreve.96.062910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 06/07/2023]
Abstract
The effect of a confining boundary on the spatial variations in granular temperature of a driven quasi-two-dimensional layer of particles is investigated experimentally. The radial drop in the relative granular temperature ΔT/T exhibits a maximum at intermediate particle numbers which coincides with a crossover from kinetic to collisional transport of energy. It is also found that at low particle numbers, the distributions of radial velocities are increasingly asymmetric as one approaches the boundary. The radial and tangential granular temperatures split, and in the tails of the radial velocity distribution there is a higher population of fast moving particles traveling away rather than towards the boundary.
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Affiliation(s)
- N D Smith
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - M I Smith
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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33
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Schockmel J, Vandewalle N, Opsomer E, Lumay G. Frustrated crystallization of a monolayer of magnetized beads under geometrical confinement. Phys Rev E 2017; 95:062120. [PMID: 28709200 DOI: 10.1103/physreve.95.062120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Indexed: 11/07/2022]
Abstract
We present a systematic experimental study of the confinement effect on the crystallization of a monolayer of magnetized beads. The particles are millimeter-scale grains interacting through the short range magnetic dipole-dipole potential induced by an external magnetic field. The grains are confined by repulsing walls and are homogeneously distributed inside the cell. A two-dimensional (2d) Brownian motion is induced by horizontal mechanical vibrations. Therefore, the balance between magnetic interaction and agitation allows investigating 2d phases through direct visualization. The effect of both confinement size and shape on the grains' organization in the low-energy state has been investigated. Concerning the confinement shape, triangular, square, pentagonal, hexagonal, heptagonal, and circular geometries have been considered. The grain organization was analyzed after a slow cooling process. Through the measurement of the averaged bond order parameter for the different confinement geometries, it has been shown that cell geometry strongly affects the ordering of the system. Moreover, many kinds of defects, whose observation rate is linked to the geometry, have been observed: disclinations, dislocations, defects chain, and also more exotic defects such as a rosette. Finally, the influence of confinement size has been investigated and we point out that no finite-size effect occurs for a hexagonal cell, but the finite-size effect changes from one geometry to another.
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Affiliation(s)
- J Schockmel
- GRASP-CESAM, Physics Department, University of Liège, B-4000 Liège, Belgium
| | - N Vandewalle
- GRASP-CESAM, Physics Department, University of Liège, B-4000 Liège, Belgium
| | - E Opsomer
- GRASP-CESAM, Physics Department, University of Liège, B-4000 Liège, Belgium
| | - G Lumay
- GRASP-CESAM, Physics Department, University of Liège, B-4000 Liège, Belgium
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34
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Napolitano S, Glynos E, Tito NB. Glass transition of polymers in bulk, confined geometries, and near interfaces. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:036602. [PMID: 28134134 DOI: 10.1088/1361-6633/aa5284] [Citation(s) in RCA: 247] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
When cooled or pressurized, polymer melts exhibit a tremendous reduction in molecular mobility. If the process is performed at a constant rate, the structural relaxation time of the liquid eventually exceeds the time allowed for equilibration. This brings the system out of equilibrium, and the liquid is operationally defined as a glass-a solid lacking long-range order. Despite almost 100 years of research on the (liquid/)glass transition, it is not yet clear which molecular mechanisms are responsible for the unique slow-down in molecular dynamics. In this review, we first introduce the reader to experimental methodologies, theories, and simulations of glassy polymer dynamics and vitrification. We then analyse the impact of connectivity, structure, and chain environment on molecular motion at the length scale of a few monomers, as well as how macromolecular architecture affects the glass transition of non-linear polymers. We then discuss a revised picture of nanoconfinement, going beyond a simple picture based on interfacial interactions and surface/volume ratio. Analysis of a large body of experimental evidence, results from molecular simulations, and predictions from theory supports, instead, a more complex framework where other parameters are relevant. We focus discussion specifically on local order, free volume, irreversible chain adsorption, the Debye-Waller factor of confined and confining media, chain rigidity, and the absolute value of the vitrification temperature. We end by highlighting the molecular origin of distributions in relaxation times and glass transition temperatures which exceed, by far, the size of a chain. Fast relaxation modes, almost universally present at the free surface between polymer and air, are also remarked upon. These modes relax at rates far larger than those characteristic of glassy dynamics in bulk. We speculate on how these may be a signature of unique relaxation processes occurring in confined or heterogeneous polymeric systems.
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Affiliation(s)
- Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, 1050 Brussels, Belgium
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35
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Cho HW, Sung BJ. The glass transition and interfacial dynamics of single strand fibers of polymers. SOFT MATTER 2017; 13:1190-1199. [PMID: 28098313 DOI: 10.1039/c6sm02468h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the glass transition and interfacial dynamics of single strand fibers of flexible polymers by employing molecular dynamics (MD) simulations along with a coarse grained model. While the polymer fiber has drawn significant attention due to its applicability in tissue engineering and stretchable electronics, its dynamic properties, especially the glass transition temperature (Tg), are yet to be understood at the molecular level. For example, there has been a controversy on the effect of the polymer fiber radius (R) on Tg: Tg decreased with a decrease in R for some polymer fibers, whereas Tg of other polymer fibers was not sensitive to R. In this article, we estimate the bond relaxation time of polymers and evaluate both Tg and fragility (m) as a function of R. We illustrate that Tg of the polymer fiber decreased with a decrease in R monotonically and also that the values of Tg follow faithfully the empirical equation proposed by Keddie et al. as a function of R, which was successfully employed to fit the values of Tg of both polyvinyl alcohol (PVA) fibers and polyethylene (PE) fibers. We also find that the dynamics of polymers at the interface between a polymer fiber and air is faster than that of polymers at the center. By employing Adam-Gibbs theory, we show that the fast interface dynamics of polymer fibers should influence the cooperative motion of monomers, which should be responsible for the decrease in Tg for smaller values of R. Near the interface there are more mobile monomers that participate in the cooperative motions of polymers. Interesting is that due to the curved surface (unlike flat polymer films) the cooperative motion of monomers is anisotropic in polymer fibers.
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Affiliation(s)
- Hyun Woo Cho
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 121-742, Republic of Korea.
| | - Bong June Sung
- Department of Chemistry and Research Institute for Basic Science, Sogang University, Seoul 121-742, Republic of Korea.
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36
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Tane M, Kimizuka H, Ichitsubo T. Two distinct crystallization processes in supercooled liquid. J Chem Phys 2017; 144:194505. [PMID: 27208956 DOI: 10.1063/1.4949329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Using molecular dynamics simulations we show that two distinct crystallization processes, depending on the temperature at which crystallization occurs, appear in a supercooled liquid. As a model for glass-forming materials, an Al2O3 model system, in which both the glass transition and crystallization from the supercooled liquid can be well reproduced, is employed. Simulations in the framework of an isothermal-isobaric ensemble indicate that the calculated time-temperature-transformation curve for the crystallization to γ(defect spinel)-Al2O3 exhibited a typical nose shape, as experimentally observed in various glass materials. During annealing above the nose temperature, the structure of the supercooled liquid does not change before the crystallization, because of the high atomic mobility (material transport). Thus, the crystallization is governed by the abrupt crystal nucleation, which results in the formation of a stable crystal structure. In contrast, during annealing below the nose temperature, the structure of the supercooled liquid gradually changes before the crystallization, and the formed crystal structure is less stable than that formed above the nose temperature, because of the restricted material transport.
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Affiliation(s)
- Masakazu Tane
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Hajime Kimizuka
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Tetsu Ichitsubo
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
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37
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Lannert M, Müller A, Gouirand E, Talluto V, Rosenstihl M, Walther T, Stühn B, Blochowicz T, Vogel M. Glycerol in micellar confinement with tunable rigidity. J Chem Phys 2016; 145:234511. [PMID: 28010095 DOI: 10.1063/1.4972009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the glassy dynamics of glycerol in the confinement of a microemulsion system, which is stable on cooling down to the glass transition of its components. By changing the composition, we vary the viscosity of the matrix, while keeping the confining geometry intact, as is demonstrated by small angle X-ray scattering. By means of 2H NMR, differential scanning calorimetry, and triplet solvation dynamics we, thus, probe the dynamics of glycerol in confinements of varying rigidity. 2H NMR results show that, at higher temperatures, the dynamics of confined glycerol is unchanged compared to bulk behavior, while the reorientation of glycerol molecules becomes significantly faster than in the bulk in the deeply supercooled regime. However, comparison of different 2H NMR findings with data from calorimetry and solvation dynamics reveals that this acceleration is not due to the changed structural relaxation of glycerol, but rather due to the rotational motion of essentially rigid glycerol droplets or of aggregates of such droplets in a more fluid matrix. Thus, independent of the matrix mobility, the glycerol dynamics remains unchanged except for the smallest droplets, where an increase of Tg and, thus, a slowdown of the structural relaxation is observed even in a fluid matrix.
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Affiliation(s)
- Michael Lannert
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Allyn Müller
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Emmanuel Gouirand
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Vincenzo Talluto
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Markus Rosenstihl
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Thomas Walther
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Bernd Stühn
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Thomas Blochowicz
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Michael Vogel
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
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38
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Wingert MC, Kwon S, Cai S, Chen R. Fluid-like Surface Layer and Its Flow Characteristics in Glassy Nanotubes. NANO LETTERS 2016; 16:7545-7550. [PMID: 27798834 DOI: 10.1021/acs.nanolett.6b03377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We show that amorphous silica and Si nanotubes can flow at room temperature under Giga-Pascal order stress when going to the nanometer scale. This creep behavior is unique for the amorphous nanotubes and is absent in crystalline Si nanotubes of similar dimensions. A core-shell model shows that there exists an approximately 1 nm thick viscoelastic "fluid-like" surface layer, which exhibits a room temperature viscosity equivalent to that of bulk glass above 1000 °C.
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Affiliation(s)
- Matthew C Wingert
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Soonshin Kwon
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Renkun Chen
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
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39
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Russo J, Tanaka H. Crystal nucleation as the ordering of multiple order parameters. J Chem Phys 2016; 145:211801. [DOI: 10.1063/1.4962166] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- John Russo
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
- School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom
| | - Hajime Tanaka
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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40
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Bollinger JA, Carmer J, Jain A, Truskett TM. Impact of solvent granularity and layering on tracer hydrodynamics in confinement. SOFT MATTER 2016; 12:9561-9574. [PMID: 27841422 DOI: 10.1039/c6sm02093c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Classic hydrodynamic arguments establish that when a spherical tracer particle is suspended between parallel walls, tracer-wall coupling mediated by the solvent will cause the tracer to exhibit position-dependent diffusivity. We investigate how the diffusivity profiles of confined tracers are impacted by the diameter size-ratio of the tracer to solvent: starting from the classic limit of infinite size-ratio (i.e., continuum solvent), we consider size-ratios of four or less to examine how hydrodynamic predictions are disrupted for systems where the tracer and solvent are of similar scale. We use computer simulations and techniques based on the Fokker-Planck formalism to calculate the diffusivity profiles of hard-sphere tracer particles in hard-sphere solvents, focusing on the dynamics perpendicular to the walls. Given wall separations of several tracer diameters, we first consider confinement between hard walls, where anisotropic structuring at the solvent lengthscale generates inhomogeneity in the tracer free-energy landscape and undermines hydrodynamic predictions locally. We then introduce confining planes that we term transparent walls, which restrict tracer and solvent center-accessibilities while completely eliminating static anisotropy, and reveal position-dependent signatures in tracer diffusivity solely attributable to confinement. With or without suppressing static heterogeneity, we find that tracer diffusivity increasingly deviates on a local basis from hydrodynamic predictions at smaller size-ratios. However, hydrodynamic theory still approximately captures spatially-averaged dynamics across the pores even for very small tracer-solvent size-ratios over a wide range of solvent densities and wall separations.
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Affiliation(s)
- Jonathan A Bollinger
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
| | - James Carmer
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
| | - Avni Jain
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
| | - Thomas M Truskett
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
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41
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Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films. Sci Rep 2016; 6:30973. [PMID: 27498698 PMCID: PMC4976322 DOI: 10.1038/srep30973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/12/2016] [Indexed: 11/24/2022] Open
Abstract
Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100−xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.
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42
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Saw S, Dasgupta C. Role of density modulation in the spatially resolved dynamics of strongly confined liquids. J Chem Phys 2016; 145:054707. [PMID: 27497572 DOI: 10.1063/1.4959942] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Confinement by walls usually produces a strong modulation in the density of dense liquids near the walls. Using molecular dynamics simulations, we examine the effects of the density modulation on the spatially resolved dynamics of a liquid confined between two parallel walls, using a resolution of a fraction of the interparticle distance in the liquid. The local dynamics is quantified by the relaxation time associated with the temporal autocorrelation function of the local density. We find that this local relaxation time varies in phase with the density modulation. The amplitude of the spatial modulation of the relaxation time can be quite large, depending on the characteristics of the wall and thermodynamic parameters of the liquid. To disentangle the effects of confinement and density modulation on the spatially resolved dynamics, we compare the dynamics of a confined liquid with that of an unconfined one in which a similar density modulation is induced by an external potential. We find several differences indicating that density modulation alone cannot account for all the features seen in the spatially resolved dynamics of confined liquids. We also examine how the dynamics near a wall depends on the separation between the two walls and show that the features seen in our simulations persist in the limit of large wall separation.
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Affiliation(s)
- Shibu Saw
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Chandan Dasgupta
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
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43
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Petach TA, Mehta A, Marks R, Johnson B, Toney MF, Goldhaber-Gordon D. Voltage-Controlled Interfacial Layering in an Ionic Liquid on SrTiO3. ACS NANO 2016; 10:4565-4569. [PMID: 26959226 DOI: 10.1021/acsnano.6b00645] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
One prominent structural feature of ionic liquids near surfaces is formation of alternating layers of anions and cations. However, how this layering responds to an applied potential is poorly understood. We focus on the structure of 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate (BMPY-FAP) near the surface of a strontium titanate (SrTiO3) electric double-layer transistor. Using X-ray reflectivity, we show that at positive bias the individual layers in the ionic liquid double layer thicken and the layering persists further away from the interface. We model the reflectivity using a modified distorted crystal model with alternating cation and anion layers, which allows us to extract the charge density and the potential near the surface. We find that the charge density is strongly oscillatory with and without applied potential and that with an applied gate bias of 4.5 V the first two layers become significantly more cation rich than at zero bias, accumulating about 2.5 × 10(13) cm(-2) excess charge density.
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Affiliation(s)
- Trevor A Petach
- Department of Physics, Stanford University , Palo Alto, California 94305, United States
| | - Apurva Mehta
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Ronald Marks
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Bart Johnson
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Michael F Toney
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
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44
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Zhang B, Cheng X. Structures and Dynamics of Glass-Forming Colloidal Liquids under Spherical Confinement. PHYSICAL REVIEW LETTERS 2016; 116:098302. [PMID: 26991205 DOI: 10.1103/physrevlett.116.098302] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Indexed: 06/05/2023]
Abstract
Recent theories predict that when a supercooled liquid approaches the glass transition, particle clusters with a special "amorphous order" nucleate within the liquid, which lead to static correlations dictating the dramatic slowdown of liquid relaxation. The prediction, however, has yet to be verified in 3D experiments. Here, we design a colloidal system, where particles are confined inside spherical cavities with an amorphous layer of particles pinned at the boundary. Using this novel system, we capture the amorphous-order particle clusters and demonstrate the development of a static correlation. Moreover, by investigating the dynamics of spherically confined samples, we reveal a profound influence of the static correlation on the relaxation of colloidal liquids. In analogy to glass-forming liquids with randomly pinned particles, we propose a simple relation for the change of the configurational entropy of confined colloidal liquids, which quantitatively explains our experimental findings and illustrates a divergent static length scale during the colloidal glass transition.
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Affiliation(s)
- Bo Zhang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Xiang Cheng
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
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45
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Ghosh S, Wijnperlé D, Mugele F, Duits MHG. Dynamics of colloids confined in microcylinders. SOFT MATTER 2016; 12:1621-1630. [PMID: 26670697 DOI: 10.1039/c5sm02581h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We studied both global and local effects of cylindrical confinement on the diffusive behavior of hard sphere (HS) colloids. Using confocal scanning laser microscopy (CSLM) and particle tracking, we measured the mean squared displacement (MSD) of 1 micron sized silica particles in water-glycerol. This combination of fluid and setup allowed us to measure MSDs in a 4-dimensional parameter space, defined by the HS volume fraction (Φ: 0.05-0.39), cylinder radius (R: 2.5-20 micron), distance to the wall (z) and lagtime (τ: 0.03-60 s). MSDs for the entire cylinder confirm earlier findings that both narrowing the cylinder and populating it cause a slower dynamics. Additionally a decrease in R was found to cause a stronger ordering of the fluid. The effect of confinement on dynamics was further examined as a function of (z) location. For the largest cylinder (with minor curvature), we found that the strong decrease in MSD near the wall, becomes much less pronounced for higher Φ. Analyzing the radial (r) and azimuthal (θ) components, we found pronounced differences in the z-dependence that were 'hidden' in the total MSD. Near the wall, the r-MSD shows a much steeper z-dependence while at larger z, it shows a remarkable anti-correlation with the (peaked) density n(z). Also the dependence of the r-MSD on lagtime correlates with n(z): diffusive in between layers, but subdiffusive inside layers. These observations bring earlier findings together, while also shedding new light on the diffusive dynamics of concentrated colloids in narrow capillaries.
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Affiliation(s)
- S Ghosh
- Physics of Complex Fluids Group, Department of Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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46
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Nie Y, Zhou Z, Hao T, Ye X, Yang W. The Distribution of Glass Transition Temperatures in Ultrathin Polymer Films Controlled by Segment Density or Interfacial Interaction. MACROMOL THEOR SIMUL 2016. [DOI: 10.1002/mats.201500062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yijing Nie
- Institute of Polymer Materials; School of Materials Science and Engineering; Jiangsu University; 301 Xuefu Road Zhenjiang 212013 China
| | - Zhiping Zhou
- Institute of Polymer Materials; School of Materials Science and Engineering; Jiangsu University; 301 Xuefu Road Zhenjiang 212013 China
| | - Tongfan Hao
- Institute of Polymer Materials; School of Materials Science and Engineering; Jiangsu University; 301 Xuefu Road Zhenjiang 212013 China
| | - Xubo Ye
- Institute of Polymer Materials; School of Materials Science and Engineering; Jiangsu University; 301 Xuefu Road Zhenjiang 212013 China
| | - Wenming Yang
- Institute of Polymer Materials; School of Materials Science and Engineering; Jiangsu University; 301 Xuefu Road Zhenjiang 212013 China
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47
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Evans CM, Kim S, Roth CB, Priestley RD, Broadbelt LJ, Torkelson JM. Role of neighboring domains in determining the magnitude and direction of Tg-confinement effects in binary, immiscible polymer systems. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.10.059] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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48
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Cheng S, Mirigian S, Carrillo JMY, Bocharova V, Sumpter BG, Schweizer KS, Sokolov AP. Revealing spatially heterogeneous relaxation in a model nanocomposite. J Chem Phys 2015; 143:194704. [DOI: 10.1063/1.4935595] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shiwang Cheng
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Stephen Mirigian
- Department of Materials Science and Chemistry, Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Jan-Michael Y. Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Vera Bocharova
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Kenneth S. Schweizer
- Department of Materials Science and Chemistry, Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Alexei P. Sokolov
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Chemistry, Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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49
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Klameth F, Vogel M. Slow Water Dynamics near a Glass Transition or a Solid Interface: A Common Rationale. J Phys Chem Lett 2015; 6:4385-4389. [PMID: 26722975 DOI: 10.1021/acs.jpclett.5b02010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Performing molecular dynamics simulations, we investigate the enormous slowdowns of water dynamics when approaching a glass transition or a solid interface. We show that both effects can be described on common grounds within a theoretical framework, which was recently proposed by Schweizer et al. and considers coupled local hopping and elastic distortion. For confined water, we correctly describe the variation of the α-relaxation time, τα, as a function of both temperature and position with respect to the interface. Exploiting our knowledge of a cooperative length scale ξ(T) from the confinement studies, we quantitatively rationalize the glassy slowdown, τα(T), and the Stokes-Einstein breakdown of bulk water. For both confined and bulk liquid, variations of the α-relaxation time are intimately related to changes of the cage-rattling amplitude.
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Affiliation(s)
- F Klameth
- Institut für Festkörperphysik, Technische Universität Darmstadt , Hochschulstr. 6, D-64289 Darmstadt, Germany
| | - M Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt , Hochschulstr. 6, D-64289 Darmstadt, Germany
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50
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Chen J, Li L, Zhou D, Wang X, Xue G. Effect of geometric curvature on vitrification behavior for polymer nanotubes confined in anodic aluminum oxide templates. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:032306. [PMID: 26465472 DOI: 10.1103/physreve.92.032306] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Indexed: 06/05/2023]
Abstract
The glass transition behavior of polystyrene (PS) nanotubes confined in cylindrical alumina nanopores was studied as a function of pore diameter (d) and polymer tube thickness (δ). Both the calorimetric glass transition temperature and the microstructure measured by a nonradiative energy transfer method indicated that the polymer nanotube, or concave polymer thin film, exhibited significant differences in vitrification behavior compared to the planar one. A closer interchain proximity and an increased T_{g} were observed for polymer nanotubes with respect to the bulk polymer. T_{g} for polymer nanotubes was primarily dependent on the curvature radius d of the template, while it was less dependent on the thickness δ of the PS tube wall in the range of 11-23 nm. For small nanotubes (d=55nm), the T_{g} increased as high as 18 °C above the bulk value. This vitrified property reverted back to the bulk value when the substrate was chemically removed, which indicated the crucial importance of the interfacial effect imposed by the hard wall with a concave geometry.
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Affiliation(s)
- Jiao Chen
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Education, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Linling Li
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Education, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Dongshan Zhou
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Education, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Xiaoliang Wang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Education, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Gi Xue
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Education, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
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