Simulating the shape memory of polyurethanes by molecular dynamics
\(^{1}\) Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, PL30387 Cracow, Poland
\(^{2}\) Doctoral School of Exact and Natural Sciences, Jagiellonian University, PL30348 Cracow, Poland
\(^{3}\) Department of Chemistry, Carleton University, 1125 Colonel By Dr, Ottawa, ON K1S 5B6, Canada
Shape memory is the unique property of polymer materials to recover their permanent shape after deformation. The most promising applications of such materials are found in medicine and aerospace [1]. To introduce this property to the material, the chemical structure should contain two different segments. Soft Segments ensure the flexibility of the polymer, allowing for the shape reorganization, while Hard Segments promote shape fixity by forming strong interchain interactions (Fig.1). The strength and character of interchain hydrogen bonds between Hard Segments have been elucidated in the previous research [2].
In this study, the shape memory property of polyurethane copolymers is investigated by means of molecular dynamics. Model systems are built based on the experimentally synthesized copolymers reported in the literature [3]. The shape memory cycle is simulated by changing temperature and pressure, to which model systems are exposed. The structure-property relationship is established based on the shape recovery ratios of copolymer models with different chemical compositions. Comparison to experimental data allows for verifying and aligning the results with the experimentally performed tests. The performed research is the foundation for further detailed multiscale investigation of shape memory copolymers morphology and physicochemical properties.
References
[1] Hager, M. D.; Bode, S.; Weber, C.; Schubert, U. S. Shape Memory Polymers: Past, Present and Future Developments. Prog Polym Sci 2015, 49–50, 3-33. https://doi.org/10.1016/j.progpolymsci.2015.04.002.
[2] Didovets, Y.; Brela, M. Z. Structure−Property Relationship between Hard Segments of Shape Memory Polyurethane Copolymers and Interchain Hydrogen Bonds: A Comprehensive Theoretical Study. J. Phys. Chem. B 2025, 129, 10504−10520. https://doi.org/10.1021/acs.jpcb.5c03305.
[3] Wang, H.; Cao, L.; Wang, X.; Lang, X.; Cong, W.; Han, L.; Zhang, H.; Zhou, H.; Sun, J.; Zong, C. Effects of Isocyanate Structure on the Properties of Polyurethane: Synthesis, Performance, and Self-Healing Characteristics. Polymers 2024, 16 (21), 3045. https://doi.org/10.3390/polym16213045.