Structural tuning of polycaprolactone based thermadapt shape memory polymer

Abstract

Dynamic covalent chemistry has reshaped our understanding of chemically crosslinked polymer networks, with broad implications on self-healing, reprocessable, and reconfigurable functional networks. Amongst them, transesterification based polycaprolactone (PCL) networks represent prototypical thermadapt shape memory polymers with unique permanent shape reconfigurability. Despite several studies on this system, structural factors that impact the solid-state plasticity behind the shape reconfigurability are poorly understood. In this work, PCL networks with precisely tunable crosslinking density and hydroxyl content were synthesized using a thiol–ene click reaction. This allows independent evaluation on how these two critical structural parameters determine the network rearrangement kinetics. In particular, we clarify an ambiguity on the role of the hydroxyl groups in such networks. This study leads to PCL based thermadapt shape memory polymers with tunable performance. On a broader basis, it also offers useful guidelines in designing transesterification based dynamic networks.