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Wang Y, Li Z, Niu K, Xia W, Giuntoli A. A Molecular Dynamics Study of Mechanical and Conformational Properties of Conjugated Polymer Thin Films. Macromolecules 2024; 57:5130-5142. [PMID: 38882199 PMCID: PMC11171455 DOI: 10.1021/acs.macromol.4c00232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/24/2024] [Accepted: 05/10/2024] [Indexed: 06/18/2024]
Abstract
Understanding and predicting the mechanical and conformational properties of conjugated polymer (CP) thin films are a central focus in flexible electronic device research. Employing molecular dynamics simulations with an architecture-transferable chemistry-specific coarse-grained (CG) model of poly(3-alkylthiophene)s (P3ATs), developed by using an energy renormalization approach, we investigate the mechanical and conformational behavior of P3AT thin films during deformation. The density profiles and measures of local mobility identify a softer interfacial layer for all films, the thickness of which does not depend on M w or side-chain length. Remarkably, Young's modulus measured via nanoindentation is more sensitive to M w than for tensile tests, which we attribute to distinct deformation mechanisms. High-M w thin films show increased toughness, whereas longer side-chain lengths of P3AT resulted in lower Young's modulus. Fractures in low-M w thin films occur through chain pullout due to insufficient chain entanglement and crazing in the plastic region. Importantly, stretching promoted both chain alignment and longer conjugation lengths of P3AT, potentially enhancing its electronic properties. For instance, at room temperature, stretching P3HT thin films to 150% increases the conjugated length of P3HT thin films from 2.7 nm to 4.7 nm, aligning with previous experimental findings and all-atom simulation results. Furthermore, high-M w thin films display elevated friction forces due to the chain accumulation on the indenter, with negligible variations in the friction coefficient across all thin film systems. These findings offer valuable insights that enhance our understanding and guide the rational design of CP thin films in flexible electronics.
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Affiliation(s)
- Yang Wang
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhaofan Li
- Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Kangmin Niu
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wenjie Xia
- Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Andrea Giuntoli
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
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Missale E, Frasconi M, Pantano MF. Ultrathin organic membranes: Can they sustain the quest for mechanically robust device applications? iScience 2023; 26:105924. [PMID: 36866039 PMCID: PMC9971879 DOI: 10.1016/j.isci.2023.105924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ultrathin polymeric films have recently attracted tremendous interest as functional components of coatings, separation membranes, and sensors, with applications spanning from environment-related processes to soft robotics and wearable devices. In order to support the development of robust devices with advanced performances, it is necessary to achieve a deep comprehension of the mechanical properties of ultrathin polymeric films, which can be significantly affected by confinement effects at the nanoscale. In this review paper, we collect the most recent advances in the development of ultrathin organic membranes with emphasis on the relationship between their structure and mechanical properties. We provide the reader with a critical overview of the main approaches for the preparation of ultrathin polymeric films, the methodologies for the investigation of their mechanical properties, and models to understand the primary effects that impact their mechanical response, followed by a discussion on the current trends for designing mechanically robust organic membranes.
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Affiliation(s)
- Elena Missale
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy
| | - Marco Frasconi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
- Corresponding author
| | - Maria F. Pantano
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 38123 Trento, Italy
- Corresponding author
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Zhang T, Wang N, Riggleman RA. Failure and Mechanical Properties of Glassy Diblock Copolymer Thin Films. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Tianren Zhang
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania19104, United States
| | - Ning Wang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana46556, United States
| | - Robert A. Riggleman
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania19104, United States
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Wang Y, Li Z, Niu K, Xia W. Energy renormalization for coarse-graining of thermomechanical behaviors of conjugated polymer. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wang G, Najafi F, Ho K, Hamidinejad M, Cui T, Walker GC, Singh CV, Filleter T. Mechanical Size Effect of Freestanding Nanoconfined Polymer Films. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02270] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guorui Wang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Farzin Najafi
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Kevin Ho
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Mahdi Hamidinejad
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Teng Cui
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Gilbert C. Walker
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Chandra Veer Singh
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario M5S 3E4, Canada
| | - Tobin Filleter
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
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Wang J, in ’t Veld PJ, Robbins MO, Ge T. Effects of Coarse-Graining on Molecular Simulation of Craze Formation in Polymer Glass. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c01969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiuling Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | | | - Mark O. Robbins
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ting Ge
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
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Zhang T, Riggleman RA. Thickness-Dependent Mechanical Failure in Thin Films of Glassy Polymer Bidisperse Blends. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01630] [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)
- Tianren Zhang
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Robert A. Riggleman
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Atomistic Investigation of Material Deformation Behavior of Polystyrene in Nanoimprint Lithography. SURFACES 2020. [DOI: 10.3390/surfaces3040043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This research investigates deformation behavior of polystyrene (PS) as a thermoplastic resist material for the thermal nanoimprint lithography (T-NIL) process. Molecular dynamics modeling was conducted on a PS substrate with dimensions 58 × 65 × 61 Å that was imprinted with a rigid, spherical indenter. The effect of indenter size, force, and imprinting duration were evaluated in terms of indentation depth, penetration depth, recovery depth, and recovery percentage of the polymer. The results show that the largest indenter, regardless of force, has the most significant impact on deformation behavior. The 40 Å indenter with a 1 µN of force caused the surface molecules to descend to the lowest point compared to the other indenters. An increase in indenter size resulted in higher penetration depth, recovery depth, and recovery percentage. Higher durations of imprint cycle (400 fs) resulted in plastic deformation of the PS material with minimal recovery (4 Å). The results of this research lay the foundation for explaining the effect of several T-NIL process parameters on virgin PS thermoplastic resist material.
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Lee S, Frank CW, Yoon DY. Interface Characteristics of Neat Melts and Binary Mixtures of Polyethylenes from Atomistic Molecular Dynamics Simulations. Polymers (Basel) 2020; 12:polym12051059. [PMID: 32384644 PMCID: PMC7284576 DOI: 10.3390/polym12051059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/22/2022] Open
Abstract
Molecular dynamics simulations of free-standing thin films of neat melts of polyethylene (PE) chains up to C150H302 and their binary mixtures with n-C13H28 are performed employing a united atom model. We estimate the surface tension values of PE melts from the atomic virial tensor over a range of temperatures, which are in good agreement with experimental results. Compared with short n-alkane systems, there is an enhanced surface segregation of methyl chain ends in longer PE chains. Moreover, the methyl groups become more segregated in the surface region with decreasing temperature, leading to the conclusion that the surface-segregation of methyl chain ends mainly arises from the enthalpic origin attributed to the lower cohesive energy density of terminal methyl groups. In the mixtures of two different chain lengths, the shorter chains are more likely to be found in the surface region, and this molecular segregation in moderately asymmetric mixtures in the chain length (C13H28 + C44H90) is dominated by the enthalpic effect of methyl chain ends. Such molecular segregation is further enhanced and dominated by the entropic effect of conformational constraints in the surface for the highly asymmetric mixtures containing long polymer chains (C13H28 + C150H3020). The estimated surface tension values of the mixtures are consistent with the observed molecular segregation characteristics. Despite this molecular segregation, the normalized density of methyl chain ends of the longer chain is more strongly enhanced, as compared with the all-segment density of the longer chain itself, in the surface region of melt mixtures. In addition, the molecular segregation results in higher order parameter of the shorter-chain segments at the surface and deeper persistence of surface-induced segmental order into the film for the longer chains, as compared with those in neat melt films.
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Affiliation(s)
- Sanghun Lee
- Department of Chemistry, Gachon University, Seongnam 13120, Gyunggido, Korea;
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
| | - Do Y. Yoon
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
- Correspondence:
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