A trap-escape model to understand the multi shape-memory and crystal–amorphous coupling effects of semi-crystalline polymers

Abstract The multi shape memory recovery of semi-crystalline shape memory polymers (SMPs) driven by multiple transitions is considered crucial for the design and application of smart materials. A trap-escape framework rooted in host–parasite kinetics is formulated to elucidate the multi-shape-memory effect and the concomitant crystal–amorphous coupling in semi-crystalline SMPs. The physical picture is conceptualized as a confining potential well in which escaping ‘host’ chains and trapped ‘parasitic’ chains orchestrate thermo-mechanical history. Avrami theory prescribes crystallization/melting rates, while Adam–Gibbs theory quantifies glass-transition dynamics through an evolving coordination number. Expressions for crystallinity ( φ c ) and frozen-phase fraction ( φ f ) are derived and coupled within a Boltzmann-type constitutive law to predict arbitrary sequences of glass- and melt-driven recoveries. The model reproduces undercooling as a natural consequence of host-chain recapture and captures the molecular origin of dual-, triple- and quadruple-SME. The framework thus offers a predictive, molecularly informed platform for designing semi-crystalline SMPs with programmable multi-state actuation.