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Yang Z, Xu X, Douglas JF, Xu WS. Confinement effect of inter-arm interactions on glass formation in star polymer melts. J Chem Phys 2024; 160:044503. [PMID: 38265089 DOI: 10.1063/5.0185412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/25/2023] [Indexed: 01/25/2024] Open
Abstract
We utilized molecular dynamic simulation to investigate the glass formation of star polymer melts in which the topological complexity is varied by altering the number of star arms (f). Emphasis was placed on how the "confinement effect" of repulsive inter-arm interactions within star polymers influences the thermodynamics and dynamics of star polymer melts. All the characteristic temperatures of glass formation were found to progressively increase with increasing f, but unexpectedly the fragility parameter KVFT was found to decrease with increasing f. As previously observed, stars having more than 5 or 6 arms adopt an average particle-like structure that is more contracted relative to the linear polymer size having the same mass and exhibit a strong tendency for intermolecular and intramolecular segregation. We systematically analyzed how varying f alters collective particle motion, dynamic heterogeneity, the decoupling exponent ζ phenomenologically linking the slow β- and α-relaxation times, and the thermodynamic scaling index γt. Consistent with our hypothesis that the segmental dynamics of many-arm star melts and thin supported polymer films should exhibit similar trends arising from the common feature of high local segmental confinement, we found that ζ increases considerably with increasing f, as found in supported polymer films with decreasing thickness. Furthermore, increasing f led to greatly enhanced elastic heterogeneity, and this phenomenon correlates strongly with changes in ζ and γt. Our observations should be helpful in building a more rational theoretical framework for understanding how molecular topology and geometrical confinement influence the dynamics of glass-forming materials more broadly.
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Affiliation(s)
- Zhenyue Yang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
- Academy for Advanced Interdisciplinary Studies, Northeast Normal University, Changchun 130024, People's Republic of China
| | - Xiaolei Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Wen-Sheng Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
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Xu WS, Sun ZY. A Thermodynamic Perspective on Polymer Glass Formation. CHINESE JOURNAL OF POLYMER SCIENCE 2023. [DOI: 10.1007/s10118-023-2951-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Xu YC, Ding L, Yao ZF, Shao Y, Wang JY, Zhang WB, Pei J. Conjugated Polymers in Solution: A Physical Perspective. J Phys Chem Lett 2023; 14:927-939. [PMID: 36669464 DOI: 10.1021/acs.jpclett.2c03600] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Excellent progress has been made in the optoelectronic properties of conjugated polymers by controlling solution-state aggregation. However, due to the wide variety and complex structures of conjugated polymers, it is still challenging to fully understand the complex aggregation process and microstructures both in solution and in the solid state. This Perspective focuses on the chain conformations and the aggregation of conjugated polymers in solution. We discuss the factors in detail which affect solution-state aggregation and microstructures from the perspective of polymer physics in solutions, including chemical structures and environmental conditions. Based on the understanding of multiple interactions of conjugated polymers in solution, strategies to regulate solid-state microstructures and obtain high-performance polymer-based devices from solution-state aggregation are summarized.
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Affiliation(s)
- Yu-Chun Xu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Li Ding
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Ze-Fan Yao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Yu Shao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Jie-Yu Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Wen-Bin Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Jian Pei
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
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Bichler KJ, Jakobi B, Klapproth A, Tominaga T, Mole RA, Schneider GJ. Side Chain Dynamics of Poly(norbornene)-g-Poly(propylene oxide) Bottlebrush Polymers. Macromol Rapid Commun 2022; 44:e2200902. [PMID: 36564928 DOI: 10.1002/marc.202200902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/06/2022] [Indexed: 12/25/2022]
Abstract
The segmental dynamics of the side chains of poly(norbornene)-g-poly(propylene oxide) (PNB-g-PPO) bottlebrush polymer in comparison to PPO is studied by quasi-elastic neutron scattering. Having experimental time and length scale information simultaneously allows to extract spatial information in addition to relaxation time. Tethering one end of the PPO side chain onto a stiff PNB backbone slows down the segmental relaxation, over the length and time scales investigated. The power law dependence of the relaxation time on the momentum transfer, Q, indicates a more heterogeneous relaxation pattern for the bottlebrush polymer, whereas the linear PPO has less deviations from a homogenous relaxation. Similar conclusions can be drawn from the time dependent mean square displacement, 〈r2 (t)〉, and the non-Gaussian parameter, α2 (t). Herein, the bottlebrush polymer shows a more restricted dynamics, whereas the linear PPO reaches 〈r2 (t)〉∝t0.5 at the highest temperature. The deviations from Gaussian behavior are evident at the α2 (t). Both samples show a decaying α2 (t). The non-Gaussian parameter supports the results from the power law dependence of the relaxation times, with lower α2 (t) values for PPO compared to those for PNB-g-PPO, pointing to less deviations from Gaussian behavior.
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Affiliation(s)
- Karin J Bichler
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, 70803, USA
| | - Bruno Jakobi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, 70803, USA
| | - Alice Klapproth
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW, 2234, Australia
| | - Taiki Tominaga
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, 319-1106, Japan
| | - Richard A Mole
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW, 2234, Australia
| | - Gerald J Schneider
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, 70803, USA.,Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana, 70803, USA
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Xu X, Douglas JF, Xu WS. Thermodynamic–Dynamic Interrelations in Glass-Forming Polymer Fluids. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01511] [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]
Affiliation(s)
- Xiaolei Xu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Wen-Sheng Xu
- 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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