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This study employs all-atomistic (AA) molecular dynamics (MD) simulations to investigate the crystallization and melting behavior of polar and nonpolar polymer chains on monolayers of graphene and graphene oxide (GO). Polyvinyl alcohol (PVA) and polyethylene (PE) are used as representative polar and nonpolar polymers, respectively. A modified order parameter is introduced to quantify the degree of two-dimensional (2D) crystallization of polymer chains. Our results show that PVA and PE chains exhibit significantly different crystallization behavior. PVA chains tend to form a more rounded, denser, and folded-stemmed lamellar structure, while PE chains tend to form an elongated straight pattern. The presence of oxidation groups on the GO substrate reduces the crystallinity of both PVA and PE chains, which is derived from the analysis of modified order parameter. Meanwhile, the crystallization patterns of polymer chains are influenced by the percentage, chemical components, and distribution of the oxidation groups. In addition, our study reveals that 2D crystalized polymer chains exhibit different melting behavior depending on their polarity. PVA chains exhibit a more molecular weight-dependent melting temperature than PE chains, which have a lower melting temperature and are relatively insensitive to molecular weight. These findings highlight the critical role of substrate and chain polarity in the crystallization and melting of polymer chains. Overall, our study provides valuable insights into the design of graphene-based polymer heterostructures and composites with tailored properties.
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Concurrent Reduction and Stabilization of Graphene Oxide Dispersion by Silk-Inspired Polymer
Silk, a popular biomaterial is used as a greener alternative of toxic reducing agent in biocompatible graphene synthesis. However, silk often forms gel uncontrollably due to its heavy chain molecular weight, and faces significant challenges in the reduction, stabilization, and dispersion process of graphene. In this contribution, we report a rapid chemical synthesis approach for a low molecular weight silk-inspired polymer via ring opening and microwave-assisted Diels-Alder aided step-growth polymerizations. This synthetic polymer with periodic sequences of hydrophilic and hydrophobic moieties not only reduces graphene oxide (GO) efficiently but enhances the dispersibility of hydrophobic reduced GO (rGO) in aqueous media.
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- Award ID(s):
- 2138438
- PAR ID:
- 10429112
- Date Published:
- Journal Name:
- ACS applied polymer materials
- ISSN:
- 2637-6105
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1021/acsapm.3c00353
