Synthesis of supramolecular networks of poly(e-caprolactone) and poly(ethylene oxide) as moisture sensitive shape-memory materials

Shape-memory polymers (SMPs) are remarkable stimuli-responsive materials able to switch from one stable macroscopic shape to another one, which can find application as smart medical devices. For this purpose, the covalent crosslinked poly(ε-caprolactone) (PCL) is widely studied because it is biocompatible, degradable, exhibit efficient thermally triggered shape memory properties, i.e. exhibit high fixity of the temporary shape and high recovery of the permanent shape and has good mechanical properties. In this work, an hydrophilic component, i.e. poly(ethylene oxide), is introduced into PCL networks in order to impart an additional shape transition triggered by hydration of the material at constant temperature.
The network of both materials is formed by reaction of the maleimide end-capped PCL stars with and furan end-capped PEO stars. This material exhibits high crosslinking density and excellent shape memory properties, after a post-curing of 48h. Moisture triggered shape transition is observed in addition to conventional thermal shape memory properties.