Molecular dynamics simulation and experimental investigation of glass transition temperature reduction in shape memory composites via GO alignment and flexible chain modification

Synergistic T g reduction via GO alignment and NGDE flexible chain modification. • MD simulations deconvolute free volume expansion and interfacial disruption mechanisms. • Sub-additive interaction between dual modification strategies revealed at molecular level. • The optimized composite achieves 58% reduction in deicing time at −15 °C. Shape memory polymers (SMPs) facilitate ice removal by undergoing stimulus-induced deformation that weakens the ice–substrate interface. However, the high glass transition temperature ( T g ) of epoxy-based SMPs increases the activation temperature and limits low-temperature use. In this study, T g was regulated through a dual strategy combining flexible-chain modification with field-assisted alignment of graphene oxide/magnetic graphene oxide (GO/MGO) nanosheets. Neopentyl glycol diglycidyl ether (NGDE) was introduced into the epoxy network as a reactive aliphatic modifier. GO/MGO nanosheets were aligned to form interfacial regions and preferential heat-transfer pathways. Thermal analysis, shape-memory tests, and de-icing experiments were performed to evaluate the composites. Molecular dynamics simulations using the COMPASS III force field were employed to analyze changes in specific volume and free volume and to clarify the underlying molecular basis of T g regulation. The combined GO/MGO alignment and NGDE modification lowered T g from 64.9 to 38.2 °C while maintaining a shape recovery ratio of 91.1%. De-icing tests at −15 °C show that the modified EP composite reduces both de-icing time and energy consumption by 58% compared with pristine EP, indicating its potential as a low-temperature shape memory de-icing material. Download: Download high-res image (303KB) Download: Download full-size image