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Tian Y, Wang Z, Dobrynin AV. When the Poisson Ratio of Polymer Networks and Gels Is Larger Than 0.5? Gels 2024; 10:463. [PMID: 39057486 PMCID: PMC11275295 DOI: 10.3390/gels10070463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 07/11/2024] [Accepted: 07/14/2024] [Indexed: 07/28/2024] Open
Abstract
We use coarse-grained molecular dynamics simulations to study deformation of networks and gels of linear and brush strands in both linear and nonlinear deformation regimes under constant pressure conditions. The simulations show that the Poisson ratio of networks and gels could exceed 0.5 in the nonlinear deformation regime. This behavior is due to the ability of the network and gel strands to sustain large reversible deformation, which, in combination with the finite strand extensibility results in strand alignment and monomer density, increases with increasing strand elongation. We developed a nonlinear network and gel deformation model which defines conditions for the Poisson ratio to exceed 0.5. The model predictions are in good agreement with the simulation results.
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Affiliation(s)
| | | | - Andrey V. Dobrynin
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA; (Y.T.); (Z.W.)
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Xue Y, Song Q, Liu Y, Smith D, Li W, Zhong M. Hierarchically Structured Nanocomposites via Mixed-Graft Block Copolymer Templating: Achieving Controlled Nanostructure and Functionality. J Am Chem Soc 2024; 146:567-577. [PMID: 38117946 DOI: 10.1021/jacs.3c10297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Integrating inorganic and polymerized organic functionalities to create composite materials presents an efficient strategy for the discovery and fabrication of multifunctional materials. The characteristics of these composites go beyond a simple sum of individual component properties; they are profoundly influenced by the spatial arrangement of these components and the resulting homo-/hetero-interactions. In this work, we develop a facile and highly adaptable approach for crafting nanostructured polymer-inorganic composites, leveraging hierarchically assembling mixed-graft block copolymers (mGBCPs) as templates. These mGBCPs, composed of diverse polymeric side chains that are covalently tethered with a defined sequence to a linear backbone polymer, self-assemble into ordered hierarchical structures with independently tuned nano- and mesoscale lattice features. Through the coassembly of mGBCPs with diversely sized inorganic fillers such as metal ions (ca. 0.1 nm), metal oxide clusters (0.5-2 nm), and metallic nanoparticles (>2 nm), we create three-dimensional filler arrays with controlled interfiller separation and arrangement. Multiple types of inorganic fillers are simultaneously integrated into the mGBCP matrix by introducing orthogonal interactions between distinct fillers and mGBCP side chains. This results in nanocomposites where each type of filler is selectively segregated into specific nanodomains with matrix-defined orientations. The developed coassembly strategy offers a versatile and scalable pathway for hierarchically structured nanocomposites, unlocking new possibilities for advanced materials in the fields of optoelectronics, sensing, and catalysis.
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Affiliation(s)
- Yazhen Xue
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Qingliang Song
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Yuchu Liu
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Daniel Smith
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Weihua Li
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Mingjiang Zhong
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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Bhat MI, Sharma P, Sitharam TG, Murthy TG. Force transmission during repose of flexible granular chains. SOFT MATTER 2023; 19:8493-8506. [PMID: 37723876 DOI: 10.1039/d3sm00526g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
We study the mechanics of standing columns formed during the repose of flexible granular chains. It is one of the many intriguing behaviours exhibited by granular materials when links capable of transmitting tension exist between particles. We develop and calibrate a discrete element method contact model to simulate the mechanics of the macroscopic flexible granular chains and conduct simulations of the angle of repose experiments of these chains by extracting a chain-filled cylinder and allowing the material to flow out under gravity and repose. We evaluate various micro-mechanical, topological and macroscopic parameters to elucidate the mechanics of the repose behaviour of chain ensembles. It is the ability of the links connecting the individual particles to transmit tensile forces along the chain backbone that provides lateral stability to the column, enabling them to stand. In particular, the contact force rearrangement inside the columns generates a self-confining radial stress near the base of the columns, which provides an important stabilizing stress.
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Lu H, Chen R, He MW, Liu H, Xue YH. A possible strategy for generating polymer chains with an entanglement-free structure. SOFT MATTER 2022; 18:6888-6898. [PMID: 36043893 DOI: 10.1039/d2sm00897a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We propose a possible strategy that may experimentally generate long polymeric chains with an entanglement-free structure. The basic idea is designing the conditions to restrict polymer chains from growing along the surface with an obviously concave curvature. This strategy is proved to effectively reduce the chance of forming both inter- and intra-molecular entanglements, which is quite similar to the self-avoiding random walking of chains on a two dimensional plane. We believe that this kind of chain growth strategy may supply a kind of possible explanation on the formation of the entanglement-free structure of chromosomes, which also have tremendously large molecular weight. Besides, this study also guides experimentalists on synthesizing specific entanglement-free functional polymeric or biological materials.
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Affiliation(s)
- Hui Lu
- Information Science School, Guangdong University of Finance and Economics, Guangzhou 510320, China.
- Key Laboratory of Theoretical Chemistry of Environment Ministry of Education, School of Chemistry, South China Normal University, Guangzhou 510006, China
| | - Ran Chen
- College of Chemistry, Jilin University, Changchun, 130023, China
| | - Min-Wei He
- Information Science School, Guangdong University of Finance and Economics, Guangzhou 510320, China.
| | - Hong Liu
- Key Laboratory of Theoretical Chemistry of Environment Ministry of Education, School of Chemistry, South China Normal University, Guangzhou 510006, China
| | - Yao-Hong Xue
- Information Science School, Guangdong University of Finance and Economics, Guangzhou 510320, China.
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Xing Z, Lu H, Shu DW, Fu YQ. Non-Euclidean geometry model for chemo-mechanical coupling in self-assembled polymers towards dynamic elasticity. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nakagawa Y, Oki Y, Da X, Singh Chandel AK, Ohta S, Ito T. Injectable bottlebrush triblock copolymer hydrogel crosslinked with ferric ions. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Xing Z, Lu H, Fu YQ. Anchoring-mediated topology signature of self-assembled elastomers undergoing mechanochromic coupling/decoupling. SOFT MATTER 2021; 17:5960-5968. [PMID: 34046654 DOI: 10.1039/d1sm00452b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Soft elastomers with their ability to integrate strain-adaptive stiffening and coloration have recently received significant research attention for application in artificial muscle and active camouflage. However, there is a lack of theoretical understanding of their complex molecular dynamics and mechanochromic coupling/decoupling. In this study, a topological dynamics model is proposed to understand the anchoring-mediated topology signature of self-assembled elastomers. Based on the constrained molecular junction model, a free-energy function is firstly formulated to describe the working principles of strain-adaptive stiffening and coloration in the self-assembled elastomer. A coupled ternary "rock-paper-scissors" model is proposed to describe the topological dynamics of self-assembly, mechanochromic coupling and mechanoresponsive stiffening of the self-assembled elastomers, in which there are three fractal geometry components in the topology network. Finally, the proposed models are verified using the experimental results reported in the literature. This study provides a fundamental approach to understand the working mechanism and topological dynamics in the self-assembled elastomers, with molecularly encoded stiffening and coloration.
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Affiliation(s)
- Ziyu Xing
- State Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China.
| | - Haibao Lu
- State Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China.
| | - Yong Qing Fu
- Smart Materials and Surfaces Laboratory, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UK.
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Starvaggi H, Tian Y, Liang H, Dobrynin AV. Bottlebrushes and Combs with Bimodal Distribution of the Side Chains: Diagram of States and Scattering Function. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Haley Starvaggi
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Yuan Tian
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Heyi Liang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Andrey V. Dobrynin
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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Rauscher PM, Schweizer KS, Rowan SJ, de Pablo JJ. Dynamics of poly[n]catenane melts. J Chem Phys 2020; 152:214901. [PMID: 32505155 DOI: 10.1063/5.0007573] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Inspired by advances in the chemical synthesis of interlocking polymer architectures, extensive molecular dynamics simulations have been conducted to study the dynamical properties of poly[n]catenanes-polymers composed entirely of interlocking rings-in the melt state. Both the degree of polymerization (number of links) and the number of beads per ring are systematically varied, and the results are compared to linear and ring polymers. A simple Rouse-like model is presented, and its analytical solution suggests a decomposition of the dynamics into "ring-like" and "linear-like" regimes at short and long times, respectively. In agreement with this picture, multiple sub-diffusive regimes are observed in the monomer mean-squared-displacements even though interchain entanglement is not prevalent in the system. However, the Rouse-type model does not account for the topological effects of the mechanical bonds, which significantly alter the dynamics at intermediate length scales both within the rings and at the chain segment scales. The stress relaxation in the system is extremely rapid and may be conveniently separated into ring-like and linear-like contributions, again in agreement with the Rouse picture. However, the viscosity has a non-monotonic dependence on the ring size for long chains, which disagrees strongly with theoretical predictions. This unexpected observation cannot be explained in terms of chain disentanglement and is inconsistent with other measures of polymer relaxation. Possible mechanisms for this behavior are proposed and implications for materials design are discussed.
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Affiliation(s)
- Phillip M Rauscher
- Pritzker School of Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Kenneth S Schweizer
- Department of Materials Science, University of Illinois, 1304 West Green Street, Urbana, Illinois 61801-3028, USA
| | - Stuart J Rowan
- Pritzker School of Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
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Wade MA, Walsh D, Lee JCW, Kelley E, Weigandt K, Guironnet D, Rogers SA. Color, structure, and rheology of a diblock bottlebrush copolymer solution. SOFT MATTER 2020; 16:4919-4931. [PMID: 32393953 PMCID: PMC11253116 DOI: 10.1039/d0sm00397b] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A structure-property-process relation is established for a diblock bottlebrush copolymer solution, through a combination of rheo-neutron scattering, imaging, and rheological measurements. Polylactic acid-b-polystyrene diblock bottlebrush copolymers were dispersed in toluene with a concentration of 175 mg ml-1, where they self-assembled into a lamellar phase. All measurements were carried out at 5 °C. The solution color, as observed in reflection, is shown to be a function of the shear rate. Under equilibrium and near-equilibrium conditions, the solution has a green color. At low shear rates the solution remains green, while at intermediate rates the solution is cyan. At the highest rates applied the solution is indigo. The lamellar spacing is shown to be a decreasing function of shear rate, partially accounting for the color change. The lamellae are oriented 'face-on' with the wall under quiescence and low shear rates, while a switch to 'edge-on' is observed at the highest shear rates, where the reflected color disappears. The intramolecular distance between bottlebrush polymers does not change with shear rate, although at high shear rates, the bottlebrush polymers are preferentially aligned in the vorticity direction within the lamellae. We therefore form a consistent relation between structure and function, spanning a wide range of length scales and shear rates.
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Affiliation(s)
- Matthew A Wade
- Chemical and Biomolecular Engineering Department, University of Illinois at Urbana-Champaign, 607 S Mathews Ave, Urbana, Illinois, USA.
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