Topological alternation from structurally adaptable to mechanically stable crosslinked polymer

Wei-Hsun Hu; Ta-Te Chen; Ryo Tamura; Kei Terayama; Siqian Wang; Ikumu Watanabe; Masanobu Naito

doi:10.1080/14686996.2021.2025426

Topological alternation from structurally adaptable to mechanically stable crosslinked polymer

Sci Technol Adv Mater. 2022 Feb 1;23(1):66-75. doi: 10.1080/14686996.2021.2025426. eCollection 2022.

Authors

Wei-Hsun Hu^{1

2}, Ta-Te Chen^{2

3}, Ryo Tamura⁴, Kei Terayama⁵, Siqian Wang¹, Ikumu Watanabe^{2

3}, Masanobu Naito^{1

2}

Affiliations

¹ Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS), Ibaraki, Japan.
² Graduate School of Science and Technology, University of Tsukuba, Ibaraki, Japan.
³ Research Center for Structural Materials, National Institute for Materials Science, Ibaraki, Japan.
⁴ International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Ibaraki, Japan.
⁵ Graduate School of Medical Life Science, Yokohama City University, Kanagawa, Japan.

Abstract

Stimuli-responsive polymers with complicated but controllable shape-morphing behaviors are critically desirable in several engineering fields. Among the various shape-morphing materials, cross-linked polymers with exchangeable bonds in dynamic network topology can undergo on-demand geometric change via solid-state plasticity while maintaining the advantageous properties of cross-linked polymers. However, these dynamic polymers are susceptible to creep deformation that results in their dimensional instability, a highly undesirable drawback that limits their service longevity and applications. Inspired by the natural ice strategy, which realizes creep reduction using crystal structure transformation, we evaluate a dynamic cross-linked polymer with tunable creep behavior through topological alternation. This alternation mechanism uses the thermally triggered disulfide-ene reaction to convert the network topology - from dynamic to static - in a polymerized bulk material. Thus, such a dynamic polymer can exhibit topological rearrangement for thermal plasticity at 130°C to resemble typical dynamic cross-linked polymers. Following the topological alternation at 180°C, the formation of a static topology reduces creep deformation by more than 85% in the same polymer. Owing to temperature-dependent selectivity, our cross-linked polymer exhibits a shape-morphing ability while enhancing its creep resistance for dimensional stability and service longevity after sequentially topological alternation. Our design enriches the design of dynamic covalent polymers, which potentially expands their utility in fabricating geometrically sophisticated multifunctional devices.

Keywords: 20 Organic and soft materials (colloids, liquid crystals, gel, polymers); 301 Chemical syntheses / processing < 300 Processing / Synthesis and Recycling; 501 Chemical analyses < 500 Characterization; Covalent adaptable network polymer; creep deformation; shape-morphing polymer material; topological alternation.

Grants and funding

This work was supported by the Core Research for Evolutional Science and Technology (CREST) program ‘Revolution material development by fusion of strong experiments with theory/data science’ of the Japan Science and Technology Agency (JST), Japan, under Grant JPMJCR19J3 and JPMJCR17J2.