1
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Bhuyan S, Chandran S, Pillai DS. Harnessing Polar Interactions Tunes the Stability of Ultrathin Polymer Solution Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:17699-17709. [PMID: 39102456 DOI: 10.1021/acs.langmuir.4c02113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
The stability of ultrathin (<100 nm) polymer films is essential in applications like protective coatings. On the contrary, their instability may actually be desirable for the emergence of self-assembled nanoscale patterns utilized in the fabrication of functional devices. Polymer solution films exhibit two distinct kinds of instabilities, viz., dewetting (long-wave) and decomposition (short-wave). Dewetting refers to the rupture of the continuous film to form isolated domains, while decomposition leads to phase separation within the polymer solution. The focus of this work is on leveraging polar interactions between the solute and solvent molecules to tune the stability of the film. A gradient dynamics-based thin film model is developed to investigate pattern formation in a thin polar polymer solution film. The Flory-Huggins theory is suitably modified by introducing a polar interaction parameter that depends upon the concentration of the polymer and the dipole moments of monomer (μ1) and solvent molecules (μ0). A linear stability analysis is performed to determine the characteristic length scale and growth rate of the instabilities. It is shown that the range of concentration space for the occurrence of the decomposition mode is directly affected by the Flory interaction parameter (χ0), μ0, and μ1, thereby serving as control parameters to tune the width of the concentration range. It is further shown that ignoring polar interactions may lead to incorrect predictions of the instability mode, including a complete loss of the decomposition mode. In addition, the long-wave dewetting length scale is found to decrease due to bulk dipolar interactions at higher polymer concentrations. Finally, numerical simulations are carried out to track the nonlinear evolution of the interface and concentration field for both the decomposition and dewetting modes of instability.
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Affiliation(s)
- Shreyanil Bhuyan
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
| | - Sivasurender Chandran
- Soft and Biological Matter Laboratory, Department of Physics, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
| | - Dipin S Pillai
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
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2
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Wei X, Bradley LC. Accessing Thin Film Wetting Regimes during Polymer Growth by Initiated Chemical Vapor Deposition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11550-11556. [PMID: 36108132 DOI: 10.1021/acs.langmuir.2c00979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We investigate the growth of a fluorinated polymer via initiated chemical vapor deposition onto a suite of isotropic and mesogenic liquids with a range of refractive indices. The polymer morphology at fluid interfaces was found to deviate from conformal films predicted by the positive spreading coefficient, and the resulting morphology is attributed to long-range van der Waals interactions during the deposition process. Experiments systematically vary the deposition conditions and compare the liquid phase (isotropic or nematic) to evaluate the effect of kinetic factors and the liquid substrate phase on the interfacial polymer morphology and spatial organization.
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Affiliation(s)
- Xiaoshuang Wei
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts01003, United States
| | - Laura C Bradley
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts01003, United States
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3
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Das A, Dey AB, Manna G, Sanyal MK, Mukherjee R. Nanoparticle-Mediated Stabilization of a Thin Polymer Bilayer. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anuja Das
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Arka Bikash Dey
- Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, West Bengal 700064, India
| | - Gouranga Manna
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru, Karnataka 560064, India
| | - Milan K. Sanyal
- Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, West Bengal 700064, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
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4
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Wu C, Wu R, Tam LH. Coarse-grained molecular simulation of the effects of carbon nanotube dispersion on the mechanics of semicrystalline polymer nanocomposites. NANOTECHNOLOGY 2021; 32:325705. [PMID: 33794512 DOI: 10.1088/1361-6528/abf458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
With the incorporation of carbon nanotubes (CNTs), CNT/polypropylene (PP) nanocomposites are found to possess enhanced mechanical properties, but the reinforcing effect is reduced at large added CNT weight percentages due to CNT aggregation. Optimizing the properties of a nanocomposite requires a fundamental understanding of the effects of CNT dispersion on the nanocomposite. In this work, coarse-grained molecular models of CNT/PP nanocomposites are constructed, which consist of randomly dispersed or aggregated CNT bundles. Our simulation results reveal that with randomly dispersed CNT bundles, the nanocomposite shows properties that continuously improve with increasing CNT contents due to the effective CNT/PP interface and the reinforcing effect of CNTs. By comparison, the nanocomposite with aggregated CNT clusters exhibits a decline in yield strength at CNT contents over 3 wt%, which results from a reduced CNT load-carrying capacity due to the formation of structural voids in the interfacial region. This study achieves anin situobservation of the structural void evolution of loaded nanocomposites, provides valuable insights into the effects of CNT dispersion on the mechanics of CNT/PP nanocomposites, and paves the way for optimizing the design of nanocomposites with superior mechanical properties by designing the CNT dispersion in the structure.
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Affiliation(s)
- Chao Wu
- School of Transportation Science and Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, People's Republic of China
| | - Ruidong Wu
- School of Transportation Science and Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, People's Republic of China
| | - Lik-Ho Tam
- School of Transportation Science and Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, People's Republic of China
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5
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Bhandaru N, Mukherjee R. Ordering in Dewetting of a Thin Polymer Bilayer with a Topographically Patterned Interface. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02559] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nandini Bhandaru
- Department of Chemical Engineering, BITS Pilani, Hyderabad, Telangana 500078, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
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6
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Das A, Mukherjee R. Feature Size Modulation in Dewetting of Nanoparticle-Containing Ultrathin Polymer Films. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anuja Das
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
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7
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Bhadauriya S, Wang X, Nallapaneni A, Masud A, Wang Z, Lee J, Bockstaller MR, Al-Enizi AM, Camp CH, Stafford CM, Douglas JF, Karim A. Observation of General Entropy-Enthalpy Compensation Effect in the Relaxation of Wrinkled Polymer Nanocomposite Films. NANO LETTERS 2021; 21:1274-1281. [PMID: 33523666 DOI: 10.1021/acs.nanolett.0c02817] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Surface-textured polymer nanocomposite (PNC) films are utilized in many device applications, and therefore understanding the relaxation behavior of such films is important. By extending an in situ wrinkle relaxation method, we observed that the thermal stability of wrinkled PNC films, both above and below the glass transition temperature (Tg), is proportional to a film's nanoparticle (polymer grafted and bare) concentration, with a slope that changes sign at a compensation temperature (Tcomp) that is determined to be in the vicinity of the film's Tg. This provides unambiguous confirmation of entropy-enthalpy compensation (EEC) as a general feature of PNC films, implying that the stability of PNC films changes from being enhanced to becoming diminished by simply passing through this characteristic temperature, a phenomenon having evident practical ramifications. We suggest EEC will also arise in films where residual stresses are associated with the film fabrication process, which is relevant to nanotech device applications.
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Affiliation(s)
- Sonal Bhadauriya
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Xiaoteng Wang
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Asritha Nallapaneni
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Ali Masud
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Zongyu Wang
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jaejun Lee
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael R Bockstaller
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Abdullah M Al-Enizi
- Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh 11451, Saudi Arabia
| | - Charles H Camp
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Christopher M Stafford
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Alamgir Karim
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
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8
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Das A, Dey AB, Chattopadhyay S, De G, Sanyal MK, Mukherjee R. Nanoparticle Induced Morphology Modulation in Spin Coated PS/PMMA Blend Thin Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15270-15282. [PMID: 33296208 DOI: 10.1021/acs.langmuir.0c02584] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The influence of adding nanoparticles on the ascast morphology of spin coated immiscible polystyrene/poly(methyl methacrylate) (PS/PMMA) thin films of different thickness (hE) and composition (RB, volume ratio of PS to PMMA) has been explored in this article. To understand the precise effect of nanoparticle addition, the morphology of PS/PMMA thin blend films spin cast from toluene on a native oxide covered silicon wafer substrate was first investigated. It is seen that in particle free films, the generic morphology of the films remains nearly unaltered with increase in hE, for RB = 3:1 and 1:3. In contrast, strong hE dependent morphology transformation is observed in films with RB = 1:1. Subsequently, thiol-capped gold nanoparticles (AuNP) containing films with different particle concentrations (CNP) were cast from the same solvent along with the polymer mixture. We observe that addition of AuNPs barely alters the generic morphology of the films with RB = 3:1. In contrast, the presence of the particles significantly influences the morphology of the films with RB = 1:1 and 1:3, particularly at higher CNP (≈10.0%). X-ray photoelectron spectroscopy and X-ray reflectivity of some samples reveal that the AuNPs tend to migrate to the free surface through the PS phase, thereby stabilizing this layer partially or fully (depending on CNP) against dewetting over a surface of adsorbed PMMA layer and influencing the ascast morphology as a function of CNP. The work is fundamentally important in understanding largely overlooked implications of nanoparticle addition on the morphology of PS/PMMA blend thin films which forms the fundamental basis for future interesting studies involving dynamics of nanoparticles within the blend thin films.
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Affiliation(s)
- Anuja Das
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Arka Bikash Dey
- Saha Institute of Nuclear Physics, Sector 1, AF Block, Bidhan Nagar, Kolkata, West Bengal 700064, India
| | - Shreyasi Chattopadhyay
- CSIR-Central Glass and Ceramic Research Institute, 196, Raja Subodh Chandra Mallick Rd, Jadavpur, Kolkata, West Bengal 700032, India
| | - Goutam De
- S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Milan K Sanyal
- Saha Institute of Nuclear Physics, Sector 1, AF Block, Bidhan Nagar, Kolkata, West Bengal 700064, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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9
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Dhara P, Mukherjee R. Influence of Substrate Surface Properties on Spin Dewetting, Texture, and Phase Transitions of 5CB Liquid-Crystal Thin Films. J Phys Chem B 2020; 124:1293-1300. [DOI: 10.1021/acs.jpcb.9b11569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Palash Dhara
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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10
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Jibril L, Chen PC, Hu J, Odom TW, Mirkin CA. Massively Parallel Nanoparticle Synthesis in Anisotropic Nanoreactors. ACS NANO 2019; 13:12408-12414. [PMID: 31613599 DOI: 10.1021/acsnano.9b05781] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This work reports a massively parallel approach for synthesizing inorganic nanoparticles (Au, Ag, Se, and mixed oxides of Cu, Co, Ni, Ge, and Ta) based upon lithographically generated arrays of square pyramidal nanoholes, which serve as nanoreactors. Particle precursor-containing polymers are spin-coated onto the nanoreactors, which upon dewetting generate a morphology of isolated polymer droplets in each nanoreactor. This dewetting process yields a well-defined and precisely controlled volume of polymer and therefore particle precursor in each nanoreactor. Subsequent stepwise annealing (first at 150 °C and then at 500 °C) yields arrays of monodisperse, site-isolated particles with sub-5 nm position control. By varying the precursor loading of the polymer, particle size can be systematically controlled in the 7-30 nm range. This work not only introduces the concept of merging block copolymer inks with nanohole arrays in the synthesis of nanoparticles but also underscores the value of the nanoreactor shape in controlling resulting particle position.
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11
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Gooneie A, Hufenus R. Polymeric Solvation Shells around Nanotubes: Mesoscopic Simulation of Interfaces in Nanochannels. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Ali Gooneie
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Rudolf Hufenus
- Laboratory of Advanced Fibers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
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12
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Li SJ, Qian HJ, Lu ZY. A simulation study on the glass transition behavior and relevant segmental dynamics in free-standing polymer nanocomposite films. SOFT MATTER 2019; 15:4476-4485. [PMID: 31111851 DOI: 10.1039/c9sm00267g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In polymer/nanoparticle composite (PNC) thin films, polymer chains experience strong confinement effects not only at the free surface area but also from nanoparticles (NPs). In this work, the influence of NP-polymer interaction and NP distribution on the polymer segmental dynamics and the glass transition behavior of PNC free-standing films are investigated through molecular dynamics simulations. We demonstrate that NPs will migrate to the film surface area and form an NP-concentrated layer when NP-polymer interactions are weak, while NPs are well dispersed in the bulk region when NP-polymer interactions are strong. In both cases, we find increases in the glass transition temperature Tg compared with the pure film without NPs, although with a different degree. The weakly interacting system has the same Tg as the pure bulk system without NPs. The NP layer formed at the surface area reduces both the mobility of the surface polymer beads and the mobility gradient in the film normal direction (MGFND), therefore resulting in an increase in the Tg which highlights the vital role of the mobile surface layer. In contrast, the NPs in the bulk region enlarge the MGFND. NPs have opposite influences on the polymer bead dynamic anisotropy when they interact weakly or strongly with polymers, weakened for the former and enhanced for the latter. These findings offer a clear picture of the segmental dynamics and glass transition behavior in free-standing PNC films with different NP-polymer interaction strengths. We hope these results will be helpful for the property design of related materials.
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Affiliation(s)
- Shu-Jia Li
- State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China.
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13
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Dhara P, Mukherjee R. Phase transition and dewetting of a 5CB liquid crystal thin film on a topographically patterned substrate. RSC Adv 2019; 9:21685-21694. [PMID: 35518868 PMCID: PMC9066433 DOI: 10.1039/c9ra02552a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/02/2019] [Indexed: 11/21/2022] Open
Abstract
Thermally induced nematic to isotropic (N–I) phase transition and dewetting of 5CB liquid crystal thin films on flat and topographically patterned substrates.
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Affiliation(s)
- Palash Dhara
- Instability and Soft Patterning Laboratory
- Department of Chemical Engineering
- Indian Institute of Technology Kharagpur
- Kharagpur
- India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory
- Department of Chemical Engineering
- Indian Institute of Technology Kharagpur
- Kharagpur
- India
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14
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Bhadauriya S, Wang X, Pitliya P, Zhang J, Raghavan D, Bockstaller MR, Stafford CM, Douglas JF, Karim A. Tuning the Relaxation of Nanopatterned Polymer Films with Polymer-Grafted Nanoparticles: Observation of Entropy-Enthalpy Compensation. NANO LETTERS 2018; 18:7441-7447. [PMID: 30398875 PMCID: PMC6537094 DOI: 10.1021/acs.nanolett.8b02514] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Polymer films provide a versatile platform in which complex functional relief patterns can be thermally imprinted with a resolution down to few nanometers. However, a practical limitation of this method is the tendency for the imprinted patterns to relax ("slump"), leading to loss of pattern fidelity over time. While increasing temperature above glass transition temperature ( Tg) accelerates the slumping kinetics of neat films, we find that the addition of polymer-grafted nanoparticles (PGNP) can greatly enhance the thermal stability of these patterns. Specifically, increasing the concentration of poly(methyl methacrylate) (PMMA) grafted titanium dioxide (TiO2) nanoparticles in the composite films slows down film relaxation dynamics, leading to enhanced pattern stability for the temperature range that we investigated. Interestingly, slumping relaxation time is found to obey an entropy-enthalpy compensation (EEC) relationship with varying PGNP concentration, similar to recently observed relaxation of strain-induced wrinkling in glassy polymer films having variable film thickness. The compensation temperature, Tcomp was found to be in the vicintity of the bulk Tg of PMMA. Our results suggest a common origin of EEC relaxation in patterned polymer thin films and nanocomposites.
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Affiliation(s)
- Sonal Bhadauriya
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325 United States
| | - Xiaoteng Wang
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325 United States
| | - Praveen Pitliya
- Department of Chemistry, Howard University, Washington, District of Columbia 20059, United States
| | - Jianan Zhang
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Dharmaraj Raghavan
- Department of Chemistry, Howard University, Washington, District of Columbia 20059, United States
| | - Michael R. Bockstaller
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Christopher M. Stafford
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Alamgir Karim
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325 United States
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15
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Weng YH, Tsao HK, Sheng YJ. Self-healing and dewetting dynamics of a polymer nanofilm on a smooth substrate: strategies for dewetting suppression. Phys Chem Chem Phys 2018; 20:20459-20467. [PMID: 30043813 DOI: 10.1039/c8cp03215g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The self-healing and dewetting dynamics of a polymer nanofilm on a smooth, partial wetting surface are explored by many-body dissipative particle dynamics. Three types of dewetting phenomena are identified, (i) spinodal decomposition, (ii) nucleation and growth, and (iii) metastable self-healing. The outcome depends on the surface wettability (θY), the polymer film thickness (h0), and the radius of the dry hole (R0). The phase diagram of the dewetting mechanism as a function of θY and h0 is obtained for a specified R0. As the surface wettability decreases (increasing θY), the critical film thickness associated with the nucleation/self-healing crossover (hc) grows so that the metastability of the film can be retained by the self-healing process. In addition to θY and R0, hc depends on the polymer length (N) as well. It is found that a longer polymer requires a thicker nanofilm to avoid dewetting by nucleation. Two strategies for dewetting suppression are proposed. The metastability of a film of polymers with a large molecular weight can be promoted either by the addition of short polymers or by employing compact polymers such as star polymers. In the latter approach, the increment of the arm number enhances the nanofilm stability.
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Affiliation(s)
- Yu-Hsuan Weng
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan.
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16
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Ferrarese Lupi F, Giammaria TJ, Miti A, Zuccheri G, Carignano S, Sparnacci K, Seguini G, De Leo N, Boarino L, Perego M, Laus M. Hierarchical Order in Dewetted Block Copolymer Thin Films on Chemically Patterned Surfaces. ACS NANO 2018; 12:7076-7085. [PMID: 29952543 DOI: 10.1021/acsnano.8b02832] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigated the dewetting process on flat and chemically patterned surfaces of ultrathin films (thickness between 2 and 15 nm) of a cylinder forming polystyrene- block-poly(methyl methacrylate) (PS- b-PMMA) spin coated on poly(styrene- r-methyl methacrylate) random copolymers (RCPs). When the PS- b-PMMA film dewets on a 2 nm-thick RCP layer, the ordering of the hexagonally packed PMMA cylinders in the dewetted structures extends over distances far exceeding the correlation length obtained in continuous block copolymer (BCP) films. As a result, micrometer-sized circular droplets featuring defectless single grains of self-assembled PS- b-PMMA with PMMA cylinders perpendicularly oriented with respect to the substrate are generated and randomly distributed on the substrate. Additionally, alignment of the droplets along micrometric lines was achieved by performing the dewetting process on large-scale chemically patterned stripes of 2 nm thick RCP films by laser lithography. By properly adjusting the periodicity of the chemical pattern, it was possible to tune and select the geometrical characteristics of the dewetted droplets in terms of maximum thickness, contact angle and diameter while maintaining the defectless single grain perpendicular cylinder morphology of the circular droplets.
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Affiliation(s)
- Federico Ferrarese Lupi
- Nanoscience and Materials Division , Istituto Nazionale di Ricerca Metrologica , Strada delle Cacce 91 , 10135 Torino , Italy
| | - Tommaso Jacopo Giammaria
- CNR-IMM , Unit of Agrate Brianza , Via C. Olivetti 2 , 20864 Agrate Brianza , Italy
- Dipartimento di Scienze e Innovazione Tecnologica (DISIT) , Università del Piemonte Orientale "A. Avogadro" , Viale T. Michel 11 , 1512 Alessandria , Italy
| | - Andrea Miti
- Dipartimento di Farmacia e Biotecnologie e Istituto di Nanoscienze del CNR (S3-Modena) , Via Irnerio, 48 , 40126 Bologna , Italy
| | - Giampaolo Zuccheri
- Dipartimento di Farmacia e Biotecnologie e Istituto di Nanoscienze del CNR (S3-Modena) , Via Irnerio, 48 , 40126 Bologna , Italy
| | | | - Katia Sparnacci
- Dipartimento di Scienze e Innovazione Tecnologica (DISIT) , Università del Piemonte Orientale "A. Avogadro" , Viale T. Michel 11 , 1512 Alessandria , Italy
| | - Gabriele Seguini
- CNR-IMM , Unit of Agrate Brianza , Via C. Olivetti 2 , 20864 Agrate Brianza , Italy
| | - Natascia De Leo
- Nanoscience and Materials Division , Istituto Nazionale di Ricerca Metrologica , Strada delle Cacce 91 , 10135 Torino , Italy
| | - Luca Boarino
- Nanoscience and Materials Division , Istituto Nazionale di Ricerca Metrologica , Strada delle Cacce 91 , 10135 Torino , Italy
| | - Michele Perego
- CNR-IMM , Unit of Agrate Brianza , Via C. Olivetti 2 , 20864 Agrate Brianza , Italy
| | - Michele Laus
- Dipartimento di Scienze e Innovazione Tecnologica (DISIT) , Università del Piemonte Orientale "A. Avogadro" , Viale T. Michel 11 , 1512 Alessandria , Italy
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17
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Sanchez-Botero L, Dimov AV, Li R, Smilgies DM, Hinestroza JP. In Situ and Real-Time Studies, via Synchrotron X-ray Scattering, of the Orientational Order of Cellulose Nanocrystals during Solution Shearing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5263-5272. [PMID: 29641208 DOI: 10.1021/acs.langmuir.7b04403] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In this manuscript, we report on the ordering of the cellulose nanocrystals (CNCs) as they experience shear forces during the casting process. To achieve these measurements, in situ and in real time, we used synchrotron-based grazing incidence wide-angle X-ray scattering (GIWAX). We believe that the GIWAX technique, although not commonly used to probe these types of phenomena, can open new avenues to gain deeper insights into film formation processes and surface-driven phenomena. In particular, we investigated the influence of solution concentration, shear-cast velocity, and drying temperature on the ordering of cellulose nanocrystals (CNCs) using GIWAXS. The films were prepared from aqueous suspensions of cellulose nanocrystals at two concentration values (7 and 9 wt %). As the films were cast, the X-ray beam was focused on a fixed position and GIWAXS patterns were recorded at regular time intervals. Structural characterization of the dry films was carried out via polarized optical microscopy and scanning electron microscopy. In addition, a rheological study of the CNC suspensions was performed. Our results show that the morphology of the CNC films was significantly influenced by shear velocity, concentration of the precursor suspension, and evaporation temperature. In contrast, we observed that the orientation parameter of the films was not significantly affected. The scattering intensity of the peak (200) was analyzed as a function of time, following a sigmoidal profile, hence indicating short- and long-range interactions within the anisotropic domains as they reached their final orientation state. A model capable of describing the resulting film morphologies is also proposed. The results and analysis presented in this manuscript provide new insights into the controlled alignment of cellulose nanocrystals under shear. This controlled alignment has significant implications in the development of advanced coatings and films currently used in a myriad of applications, such as catalysis, optics, electronics, and biomedicine.
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Affiliation(s)
| | | | - Ruipeng Li
- Cornell High Energy Synchrotron Source (CHESS) , Ithaca , New York 14853 , United States
| | - Detlef-M Smilgies
- Cornell High Energy Synchrotron Source (CHESS) , Ithaca , New York 14853 , United States
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18
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Dhara P, Bhandaru N, Das A, Mukherjee R. Transition from Spin Dewetting to continuous film in spin coating of Liquid Crystal 5CB. Sci Rep 2018; 8:7169. [PMID: 29740096 PMCID: PMC5940909 DOI: 10.1038/s41598-018-25504-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/13/2018] [Indexed: 12/03/2022] Open
Abstract
Spin dewetting refers to spontaneous rupture of the dispensed solution layer during spin coating, resulting in isolated but periodic, regular sized domains of the solute and is pre-dominant when the solute concentration (Cn) is very low. In this article we report how the morphology of liquid crystal (LC) 5CB thin films coated on flat and patterned PMMA substrate transform from spin dewetted droplets to continuous films with increase in Cn. We further show that within the spin dewetted regime, with gradual increase in the solute concentration, periodicity of the isotropic droplets (λD) as well as their mean diameter (dD), gradually decreases, till the film becomes continuous at a critical concentration (Cn*). Interestingly, the trend that λD reduces with increase in Cn is exact opposite to what is observed in thermal/solvent vapor induced dewetting of a thin film. The spin dewetted droplets exhibit transient Radial texture, in contrast to Schlieren texture observed in elongated threads and continuous films of 5CB, which remains in the Nematic phase at room temperature. Finally we show that by casting the film on a grating patterned substrate it becomes possible to align the spin dewetted droplets along the contours substrate patterns.
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Affiliation(s)
- Palash Dhara
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, Pin-721302, India
| | - Nandini Bhandaru
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, Pin-721302, India
| | - Anuja Das
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, Pin-721302, India
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, Pin-721302, India.
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19
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Dewetting Kinetics of Thin Polymer Films with Different Architectures: Effect of Polymer Adsorption. CHINESE JOURNAL OF POLYMER SCIENCE 2018. [DOI: 10.1007/s10118-018-2111-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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20
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Liu X, Bhandaru N, Banik M, Wang X, Al-Enizi AM, Karim A, Mukherjee R. Capillary Force Lithography Pattern-Directed Self-Assembly (CFL-PDSA) of Phase-Separating Polymer Blend Thin Films. ACS OMEGA 2018; 3:2161-2168. [PMID: 31458520 PMCID: PMC6641379 DOI: 10.1021/acsomega.7b02078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 02/09/2018] [Indexed: 06/10/2023]
Abstract
We report capillary force lithography pattern-directed self-assembly (CFL-PDSA), a facile technique for patterning immiscible polymer blend films of polystyrene (PS)/poly(methyl methacrylate) (PMMA), resulting in a highly ordered phase-separated morphology. The pattern replication is achieved by capillary force lithography (CFL), by annealing the film beyond the glass transition temperature of both the constituent polymers, while confining it between a patterned cross-linked poly(dimethyl siloxane) (PDMS) stamp and the silicon substrate. As the pattern replication takes place because of rise of the polymer meniscus along the confining stamp walls, higher affinity of PMMA toward the oxide-coated silicon substrate and of PS toward cross-linked PDMS leads to well-controlled vertically patterned phase separation of the two constituent polymers during thermal annealing. Although a perfect negative replica of the stamp pattern is obtained in all cases, the phase-separated morphology of the films under pattern confinement is strongly influenced by the blend composition and annealing time. The phase-separated domains coarsen with time because of migration of the two components into specific areas, PS into an elevated mesa region and PMMA toward the substrate, because of preferential wetting. We show that a well-controlled, phase-separated morphology is achieved when the blend ratio matches the volume ratio of the elevated region to the base region in the patterned films. The proposed top-down imprint patterning of blends can be easily made roll-to-roll-compatible for industrial adoption.
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Affiliation(s)
- Xiangyu Liu
- Department
of Polymer Engineering, University
of Akron, Akron, Ohio 44325, United
States
| | - Nandini Bhandaru
- Instability
and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Meneka Banik
- Instability
and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
| | - Xiaoteng Wang
- Department
of Polymer Engineering, University
of Akron, Akron, Ohio 44325, United
States
| | - Abdullah M. Al-Enizi
- Chemistry
Department, Faculty of Science, King Saud
University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Alamgir Karim
- Department
of Polymer Engineering, University
of Akron, Akron, Ohio 44325, United
States
| | - Rabibrata Mukherjee
- Instability
and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India
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21
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Kato T, Liu Y, Murai Y, Kubo M, Shoji E, Tsukada T, Takami S, Adschiri T. Effect of Surface Modifier of Nanoparticles on Dewetting Behaviors of Polymer Nanocomposite Thin Films. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 2018. [DOI: 10.1252/jcej.17we241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Takumi Kato
- Department of Chemical Engineering, Tohoku University
| | - Yang Liu
- Department of Chemical Engineering, Tohoku University
| | - Yuuta Murai
- Department of Chemical Engineering, Tohoku University
| | - Masaki Kubo
- Department of Chemical Engineering, Tohoku University
| | - Eita Shoji
- Department of Chemical Engineering, Tohoku University
| | - Takao Tsukada
- Department of Chemical Engineering, Tohoku University
| | - Seiichi Takami
- Department of Materials Process Engineering, Nagoya University
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22
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Barkley DA, Jiang N, Sen M, Endoh MK, Rudick JG, Koga T, Zhang Y, Gang O, Yuan G, Satija SK, Kawaguchi D, Tanaka K, Karim A. Chain Conformation near the Buried Interface in Nanoparticle-Stabilized Polymer Thin Films. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01187] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
| | | | | | | | | | | | | | - Oleg Gang
- Department
of Chemical Engineering and Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Guangcui Yuan
- Center for
Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sushil K. Satija
- Center for
Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | | | | | - Alamgir Karim
- College of
Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325-0301, United States
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23
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Cao P, Bai P, Omrani AA, Xiao Y, Meaker KL, Tsai HZ, Yan A, Jung HS, Khajeh R, Rodgers GF, Kim Y, Aikawa AS, Kolaczkowski MA, Liu Y, Zettl A, Xu K, Crommie MF, Xu T. Preventing Thin Film Dewetting via Graphene Capping. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1701536. [PMID: 28722188 DOI: 10.1002/adma.201701536] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 04/11/2017] [Indexed: 05/27/2023]
Abstract
A monolayer 2D capping layer with high Young's modulus is shown to be able to effectively suppress the dewetting of underlying thin films of small organic semiconductor molecule, polymer, and polycrystalline metal, respectively. To verify the universality of this capping layer approach, the dewetting experiments are performed for single-layer graphene transferred onto polystyrene (PS), semiconducting thienoazacoronene (EH-TAC), gold, and also MoS2 on PS. Thermodynamic modeling indicates that the exceptionally high Young's modulus and surface conformity of 2D capping layers such as graphene and MoS2 substantially suppress surface fluctuations and thus dewetting. As long as the uncovered area is smaller than the fluctuation wavelength of the thin film in a dewetting process via spinodal decomposition, the dewetting should be suppressed. The 2D monolayer-capping approach opens up exciting new possibilities to enhance the thermal stability and expands the processing parameters for thin film materials without significantly altering their physical properties.
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Affiliation(s)
- Peigen Cao
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Peter Bai
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Arash A Omrani
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Yihan Xiao
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Kacey L Meaker
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Hsin-Zon Tsai
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Aiming Yan
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Han Sae Jung
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Ramin Khajeh
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Griffin F Rodgers
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Youngkyou Kim
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Andrew S Aikawa
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Mattew A Kolaczkowski
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Yi Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Alex Zettl
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy NanoSciences Institute, University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ke Xu
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Michael F Crommie
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy NanoSciences Institute, University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ting Xu
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
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24
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Wang L, Xu L, Liu B, Shi T, Jiang S, An L. The influence of polymer architectures on the dewetting behavior of thin polymer films: from linear chains to ring chains. SOFT MATTER 2017; 13:3091-3098. [PMID: 28393155 DOI: 10.1039/c7sm00379j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The dewetting behavior of ring polystyrene (RPS) film and linear polystyrene (LPS) film on silanized Si substrates with different grafting densities and PDMS substrate was investigated. Results showed that polymer architectures greatly influenced the dewetting behavior of the thin polymer film. On the silanized Si substrate with 69% grafting density, RPS chains exhibited stronger adsorption compared with LPS chains, and as a result the wetting layer formed more easily. For LPS films, with a decreased annealing temperature, the stability of the polymer film changed from non-slip dewetting via apparent slip dewetting to apparently stable. However, for RPS films, the polymer film stability switched from apparent slip dewetting to apparently stable. On the silanized Si substrate with 94% grafting density, the chain adsorption became weaker and the dewetting processes were faster than that on the substrate with 69% grafting density at the same experimental temperature for both the LPS and RPS films. Moreover, on the PDMS substrate, LPS films always showed non-slip dewetting, while the dewetting kinetics of RPS films switched from non-slip dewetting to slip dewetting behaviour. Forming the wetting layer strongly influenced the stability and dewetting behavior of the thin polymer films.
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Affiliation(s)
- Lina Wang
- School of Materials Science and Engineering, Tianjin University, Tianjin 300072, P. R. China.
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25
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Teng CY, Sheng YJ, Tsao HK. Surface Segregation and Bulk Aggregation in an Athermal Thin Film of Polymer-Nanoparticle Blends: Strategies of Controlling Phase Behavior. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2639-2645. [PMID: 28221802 DOI: 10.1021/acs.langmuir.6b04681] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The phase behavior of an athermal film of a polymer-nanoparticle blend (PNB) driven by depletion attraction is investigated by dissipative particle dynamics for nanospheres and nanocubes. Surface segregation is observed at low nanoparticle concentrations, while bulk aggregation is seen at high concentrations. Surface excess and the aggregation number can be controlled by tuning the nanoparticle concentration. As surface-roughened or polymer-grafted nanoparticles are used, uniform PNBs are acquired due to the lack of depletion. Thus, addition of surface-roughened nanoparticles into PNBs of smooth nanoparticles can be employed to tune the phase characteristics. It is found that bulk aggregation is suppressed for both polymer-nanosphere and polymer-nanocube blends. However, surface segregation is impeded for polymer-nanosphere blend but enhanced for polymer-nanocube blend owing to the distinct influence of the nanoparticle shape on depletion.
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Affiliation(s)
- Chih-Yu Teng
- Department of Chemical Engineering, National Taiwan University , Taipei 106, Taiwan
| | - Yu-Jane Sheng
- Department of Chemical Engineering, National Taiwan University , Taipei 106, Taiwan
| | - Heng-Kwong Tsao
- Department of Chemical and Materials Engineering, Department of Physics, National Central University , Jhongli 320, Taiwan
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26
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Choukourov A, Kylián O, Petr M, Vaidulych M, Nikitin D, Hanuš J, Artemenko A, Shelemin A, Gordeev I, Kolská Z, Solař P, Khalakhan I, Ryabov A, Májek J, Slavínská D, Biederman H. RMS roughness-independent tuning of surface wettability by tailoring silver nanoparticles with a fluorocarbon plasma polymer. NANOSCALE 2017; 9:2616-2625. [PMID: 28155944 DOI: 10.1039/c6nr08428a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and maintaining the multivalued character of the surface roughness. The growth (β) and the dynamic (1/z) exponents are close to zero and the interface bears the features of self-affinity. The presence of inter-particle voids leads to heterogeneous wetting with an apparent water contact angle θa = 135°. The multivalued nanotopography results in two possible positions for the water droplet meniscus, yet strong water adhesion indicates that the meniscus is located at the lower part of the spherical nanofeatures. In the late regime, the inter-particle voids become filled and the interface acquires a single valued character. The plasma polymer proceeds to grow on the thus-roughened surface whereas the nanoparticles keep emerging away from the substrate. The RMS roughness remains invariable and lateral correlations propagate with 1/z = 0.27. The surface features multiaffinity which is given by different evolution of length scales associated with the nanoparticles and with the plasma polymer. The wettability turns to the homogeneous wetting state.
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Affiliation(s)
- A Choukourov
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - O Kylián
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - M Petr
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - M Vaidulych
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - D Nikitin
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - J Hanuš
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - A Artemenko
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16200 Prague, Czech Republic
| | - A Shelemin
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - I Gordeev
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16200 Prague, Czech Republic
| | - Z Kolská
- J. E. Purkyne University, Faculty of Science, České mládeže 8, 40096 Ústí nad Labem, Czech Republic
| | - P Solař
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - I Khalakhan
- Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, V Holešovičkách 2, 18000 Prague, Czech Republic
| | - A Ryabov
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - J Májek
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - D Slavínská
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
| | - H Biederman
- Charles University, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holešovičkách 2, 18000 Prague, Czech Republic.
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27
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Teng CY, Sheng YJ, Tsao HK. Particle size-induced transition between surface segregation and bulk aggregation in a thin film of athermal polymer-nanoparticle blends. J Chem Phys 2017; 146:014904. [DOI: 10.1063/1.4973608] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chih-Yu Teng
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Yu-Jane Sheng
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Heng-Kwong Tsao
- Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan
- Department of Physics, National Central University, Jhongli 320, Taiwan
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28
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29
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Han X, Hou J, Xie J, Yin J, Tong Y, Lu C, Möhwald H. Synergism of Dewetting and Self-Wrinkling To Create Two-Dimensional Ordered Arrays of Functional Microspheres. ACS APPLIED MATERIALS & INTERFACES 2016; 8:16404-16411. [PMID: 27300307 DOI: 10.1021/acsami.6b03036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Here we report a simple, novel, yet robust nonlithographic method for the controlled fabrication of two-dimensional (2-D) ordered arrays of polyethylene glycol (PEG) microspheres. It is based on the synergistic combination of two bottom-up processes enabling periodic structure formation for the first time: dewetting and the mechanical wrinkle formation. The deterministic dewetting results from the hydrophilic polymer PEG on an incompatible polystyrene (PS) film bound to a polydimethylsiloxane (PDMS) substrate, which is directed both by a wrinkled template and by the template-directed in-situ self-wrinkling PS/PDMS substrate. Two strategies have been introduced to achieve synergism to enhance the 2-D ordering, i.e., employing 2-D in-situ self-wrinkling substrates and boundary conditions. As a result, we achieve highly ordered 2-D arrays of PEG microspheres with desired self-organized microstructures, such as the array location (e.g., selectively on the crest/in the valley of the wrinkles), diameter, spacing of the microspheres, and array direction. Additionally, the coordination of PEG with HAuCl4 is utilized to fabricate 2-D ordered arrays of functional PEG-HAuCl4 composite microspheres, which are further converted into different Au nanoparticle arrays. This simple versatile combined strategy could be extended to fabricate highly ordered 2-D arrays of other functional materials and achieve desirable properties and functionalities.
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Affiliation(s)
- Xue Han
- School of Materials Science and Engineering, Tianjin University , Tianjin 300072, People's Republic of China
| | - Jing Hou
- School of Materials Science and Engineering, Tianjin University , Tianjin 300072, People's Republic of China
| | - Jixun Xie
- School of Materials Science and Engineering, Tianjin University , Tianjin 300072, People's Republic of China
| | - Jian Yin
- School of Materials Science and Engineering, Tianjin University , Tianjin 300072, People's Republic of China
| | - Yi Tong
- School of Materials Science and Engineering, Tianjin University , Tianjin 300072, People's Republic of China
| | - Conghua Lu
- School of Materials Science and Engineering, Tianjin University , Tianjin 300072, People's Republic of China
| | - Helmuth Möhwald
- Department of Interfaces, Max Planck Institute of Colloids and Interfaces , Potsdam 14424, Germany
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30
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Zhang H, Xu L, Lai Y, Shi T. Influence of film structure on the dewetting kinetics of thin polymer films in the solvent annealing process. Phys Chem Chem Phys 2016; 18:16310-6. [PMID: 27254136 DOI: 10.1039/c6cp02447e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process.
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Affiliation(s)
- Huanhuan Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
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31
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Magnetic nanoparticle film reconstruction modulated by immersion within DMSA aqueous solution. Sci Rep 2016; 6:18202. [PMID: 27008984 PMCID: PMC4806361 DOI: 10.1038/srep18202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/13/2015] [Indexed: 11/08/2022] Open
Abstract
The process of reconstruction of pre-fabricated films comprising maghemite nanoparticles deposited onto flat glass substrates triggered by immersion into aqueous solutions of meso-2,3-dimercaptosuccinic acid (DMSA) at increasing concentration (0.025, 0.050, and 0.100 mol/L) is herein reported. The evolution of this process was assessed by measuring the time (t) dependence of the particle analysis histogram width (W) extracted from atomic force microscopy images. Furthermore, a physical picture to model the film reconstruction which provides reconstruction time constants associated to single particles (τ1) and small agglomerates (τn), the key units associated to the process, ranging from τ1 = 2.9 and τn = 3.4 hour (0.025 mol/L) to τ1 = 5.1 and τn = 4.6 hour (0.100 mol/L) is proposed. The nanoparticle-based film reconstruction triggered by an exogenous stimulus, the use of the W versus t data to describe the process and the model picture accounting for the recorded data have not been previously reported.
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Thermally amendable and thermally stable thin film of POSS tethered Poly(methyl methacrylate) (PMMA) synthesized by ATRP. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2015.12.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Bhandaru N, Das A, Mukherjee R. Confinement induced ordering in dewetting of ultra-thin polymer bilayers on nanopatterned substrates. NANOSCALE 2016; 8:1073-1087. [PMID: 26658720 DOI: 10.1039/c5nr06690e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the dewetting of a thin bilayer of polystyrene (PS) and poly(methylmethacrylate) (PMMA) on a topographically patterned nonwettable substrate comprising an array of pillars, arranged in a square lattice. With a gradual increase in the concentration of the PMMA solution (Cn-PMMA), the morphology of the bottom layer changes to: (1) an aligned array of spin dewetted droplets arranged along substrate grooves at very low Cn-PMMA; (2) an interconnected network of threads surrounding each pillar at intermediate Cn-PMMA; and (3) a continuous bottom layer at higher Cn-PMMA. On the other hand the morphology of the PS top layer depends largely on the nature of the pre-existing bottom layer, in addition to Cn-PS. An ordered array of PMMA core-PS shell droplets forms right after spin coating when both Cn-PMMA and Cn-PS are very low. Bilayers with all other initial configurations evolve during thermal annealing, resulting in a variety of ordered structures. Unique morphologies realized include laterally coexisting structures of the two polymers confined within the substrate grooves due to initial rupture of the bottom layer on the substrate followed by a squeezing flow of the top layer; an array of core-shell and single polymer droplets arranged in an alternating order etc., to highlight a few. Such structures cannot be fabricated by any stand-alone lithography technique. On the other hand, in some cases the partially dewetted bottom layer imparts stability to an intact top PS layer against dewetting. Apart from ordering, under certain specific conditions significant miniaturization and downsizing of dewetted feature periodicity and dimension as compared to dewetting of a single layer on a flat substrate is observed. With the help of a morphology phase diagram we show that ordering is achieved over a wide combination of Cn-PMMA and Cn-PS, though the morphology and dewetting pathway differs significantly with variation in the thickness of the individual layers.
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Affiliation(s)
- Nandini Bhandaru
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, Pin 721302, India.
| | - Anuja Das
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, Pin 721302, India.
| | - Rabibrata Mukherjee
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, West Bengal, Pin 721302, India.
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Cai XJ, Yuan HM, Blencowe A, Qiao GG, Genzer J, Spontak RJ. Film-Stabilizing Attributes of Polymeric Core-Shell Nanoparticles. ACS NANO 2015; 9:7940-7949. [PMID: 26146164 DOI: 10.1021/acsnano.5b00237] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Self-organization of nanoparticles into stable, molecularly thin films provides an insightful paradigm for manipulating the manner in which materials interact at nanoscale dimensions to generate unique material assemblies at macroscopic length scales. While prior studies in this vein have focused largely on examining the performance of inorganic or organic/inorganic hybrid nanoparticles (NPs), the present work examines the stabilizing attributes of fully organic core-shell microgel (CSMG) NPs composed of a cross-linked poly(ethylene glycol dimethacrylate) (PEGDMA) core and a shell of densely grafted, but relatively short-chain, polystyrene (PS) arms. Although PS homopolymer thin films measuring from a few to many nanometers in thickness, depending on the molecular weight, typically dewet rapidly from silica supports at elevated temperatures, spin-coated CSMG NP films measuring as thin as 10 nm remain stable under identical conditions for at least 72 h. Through the use of self-assembled monolayers (SAMs) to alter the surface of a flat silica-based support, we demonstrate that such stabilization is not attributable to hydrogen bonding between the acrylic core and silica. We also document that thin NP films consisting of three or less layers (10 nm) and deposited onto SAMs can be fully dissolved even after extensive thermal treatment, whereas slightly thicker films (40 nm) on Si wafer become only partially soluble during solvent rinsing with and without sonication. Taken together, these observations indicate that the present CSMG NP films are stabilized primarily by multidirectional penetration of relatively short, unentangled NP arms caused by NP layering, rather than by chain entanglement as in linear homopolymer thin films. This nanoscale "velcro"-like mechanism permits such NP films, unlike their homopolymer counterparts of comparable chain length and thickness, to remain intact as stable, free-floating sheets on water, and thus provides a viable alternative to ultrathin organic coating strategies.
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Affiliation(s)
- Xiao-Jing Cai
- Department of Chemical & Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695-7905, United States
| | - Hao-Miao Yuan
- Department of Chemical & Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695-7905, United States
| | - Anton Blencowe
- Department of Chemical & Biomolecular Engineering, University of Melbourne , Parkville, Victoria 3010, Australia
- Mawson Institute, Division of ITEE, The University of South Australia , Mawson Lakes, South Australia 5095, Australia
| | - Greg G Qiao
- Department of Chemical & Biomolecular Engineering, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Jan Genzer
- Department of Chemical & Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695-7905, United States
| | - Richard J Spontak
- Department of Chemical & Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695-7905, United States
- Department of Materials Science & Engineering, North Carolina State University , Raleigh, North Carolina 27695-7907, United States
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Xavier P, Bose S. Mapping the intriguing transient morphologies and the demixing behavior in PS/PVME blends in the presence of rod-like nanoparticles. Phys Chem Chem Phys 2015; 17:14972-85. [PMID: 25982342 DOI: 10.1039/c5cp01865j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The demixing behavior, transient morphologies and mechanism of phase separation in PS/PVME blends were greatly altered in the presence of a very low concentration of rod-like particles (multiwall carbon nanotubes, MWNTs). This phenomenon is due to the specific interaction of one of the phases (PVME) with the anisotropic MWNTs, which creates a heterogeneous environment in the blend. This specific interaction alters the chain dynamics in the interfacial region as against the bulk. A comprehensive analysis using isochronal temperature sweep was performed to understand the demixing temperature in the blends. The evolution of phase morphology as a function of time and temperature was assessed by polarizing optical microscopy (POM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The addition of MWNTs increased the rheological demixing temperature and the spinodal temperature in almost all the compositions. The intriguing transient morphologies were mapped, which varied from nucleation and growth to coalescence-induced viscoelastic phase separation (C-VPS) in PVME-rich blends, to spinodal decomposition in the near-critical compositions, to transient gel-induced VPS (T-VPS) in the PS-rich compositions. Mapping of the morphology development displayed two types of fracture mechanisms: ductile fracture for near-critical compositions and brittle fracture for off-critical composition. The change in the phase separation mechanism in the presence of MWNTs was due to the variation in dynamic asymmetry brought about by these anisotropic particles. All these observations were correlated by POM, SEM and AFM studies. The length of the cooperatively rearranging region (CRR), as evaluated using modulated differential scanning calorimetry (MDSC) measurements, was found to be composition-independent. The observed variation of effective glass transition of PVME (low Tg component) on blending with PS (high Tg component) and by the addition of MWNTs accounts for the dynamic heterogeneity introduced by MWNTs in the system.
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Affiliation(s)
- Priti Xavier
- Department of Materials Engineering, Indian Institute of Science, Bangalore-560012, India.
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Dattani R, Cabral JT. Polymer fullerene solution phase behaviour and film formation pathways. SOFT MATTER 2015; 11:3125-3131. [PMID: 25739808 DOI: 10.1039/c5sm00053j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the phase behaviour of polymer/fullerene/solvent ternary mixtures and its consequence for the morphology of the resulting composite thin films. We focus particularly on solutions of polystyrene (PS), C60 fullerene and toluene, which are examined by static and dynamic light scattering, and films obtained from various solution ages and thermal annealing conditions, using atomic force and light microscopy. Unexpectedly, the solution phase behaviour below the polymer overlap concentration, c*, is found to be described by a simple excluded volume argument (occupied by the polymer chains) and the neat C60/solvent miscibility. Scaling consistent with full exclusion is found when the miscibility of the fullerene in the solvent is much lower than that of the polymer, giving way to partial exclusion with more soluble fullerenes (phenyl-C61-butyric acid methyl ester, PCBM) and a less asymmetric solvent (chlorobenzene), employed in photovoltaic devices. Spun cast and drop cast films were prepared from PS/C60/toluene solutions across the phase diagram to yield an identical PS/C60 composition and film thickness, resulting in qualitatively different morphologies in agreement with our measured solution phase boundaries. Our findings are relevant to the solution processing of polymer/fullerene composites (including organic photovoltaic devices), which generally require effective solubilisation of fullerene derivatives and polymer pairs in this concentration range, and the design of well-defined thin film morphologies.
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Affiliation(s)
- Rajeev Dattani
- Department of Chemical Engineering, Centre for Plastic Electronics, Imperial College London, London, SW7 2AZ, UK.
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Bhandaru N, Goohpattader PS, Faruqui D, Mukherjee R, Sharma A. Solvent-vapor-assisted dewetting of prepatterned thin polymer films: control of morphology, order, and pattern miniaturization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3203-14. [PMID: 25692553 DOI: 10.1021/la5045738] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ultrathin (<100 nm) unstable polymer films exposed to a solvent vapor dewet by the growth of surface instability, the wavelength (λ) of which depends on the film thickness (h(f)). While the dewetting of a flat polymer thin film results in random structures, we show that the dewetting of a prepatterned film results in myriad ordered mesoscale morphologies under specific conditions. Such a film undergoes rupture over the thinnest parts when the initial local thickness of these zones (h(rm)) is lower than a limiting thickness h(lim) ≈ 10 nm. Additionally, the width of the pattern grooves (l(s)) must be wider than λ(s) corresponding to a flat film having a thickness of h(rm) for pattern-directed dewetting to take place over surface-tension-induced flattening. We first present an experimentally obtained morphology phase diagram that captures the conditions where a transition from surface-tension-induced flattening to pattern-directed-rupture takes place. Subsequently, we show the versatility of this technique in achieving a variety of aligned mesopatterns starting from a prepatterned film with simple grating geometry. The morphology of the evolving patterns depends on several parameters such as the initial film thickness (h(f)), prepattern amplitude (h(st)), duration of solvent vapor exposure (SVE), and wettability of the stamp used for patterning. Periodic rupture of the film at regular intervals imposes directionality on the evolving patterns, resulting in isolated long threads/cylindrical ridges of polymers, which subsequently disintegrate into an aligned array of droplets due to Rayleigh-Plateau instability under specific conditions. Other patterns such as a double periodic array of droplets and an array of holes are also possible to obtain. The evolution can be interrupted at any intermediate stage by terminating the solvent vapor annealing, allowing the creation of pattern morphology on demand. The created patterns are significantly miniaturized in size as compared to features obtained from dewetting a flat film with the same hf.
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Affiliation(s)
- Nandini Bhandaru
- †Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Pin - 721302, Kharagpur, West Bengal, India
| | - Partho Sarathi Goohpattader
- ‡Department of Chemical Engineering and Nanoscience Center, Indian Institute of Technology Kanpur, 208016, Uttar Pradesh, Kanpur, India
| | - Danish Faruqui
- ‡Department of Chemical Engineering and Nanoscience Center, Indian Institute of Technology Kanpur, 208016, Uttar Pradesh, Kanpur, India
| | - Rabibrata Mukherjee
- †Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Pin - 721302, Kharagpur, West Bengal, India
- ‡Department of Chemical Engineering and Nanoscience Center, Indian Institute of Technology Kanpur, 208016, Uttar Pradesh, Kanpur, India
| | - Ashutosh Sharma
- ‡Department of Chemical Engineering and Nanoscience Center, Indian Institute of Technology Kanpur, 208016, Uttar Pradesh, Kanpur, India
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