Efficient moisture-sensitive shape-memory materials composed of supramolecular network of poly(ε-caprolactone) and poly(ethylene oxide)

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, covalent crosslinked poly(ε-caprolactone) (PCL) is widely studied because it is biocompatible, degradable, exhibits efficient thermally triggered shape memory properties, i.e. high fixity of the temporary shape, 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 furan end-capped PEO stars. After melt-mixing and a post-curing of 48h, this material shows high crosslinking density as demonstrated by swelling behavior, good mechanical properties and excellent shape memory properties,. Moreover, moisture triggered shape transition is observed in addition to conventional thermal shape memory properties.