Shape-memory polymer networks from sol-gel cross-linked alkoxysilane-terminated poly(e-caprolactone)

A novel type of covalently cross-linked semi-crystalline polymer with shape-memory and biocompatibility properties was prepared from alkoxysilane-terminated poly(epsilon-caprolactone) (PCL) by sol-gel process that allowed the generation of silica-like cross-linking points. A fine tuning of the cross-linking density and thermal properties (melting temperature) of the materials was obtained by controlling the molecular weight of the PCL precursor (and thus the molecular structure of the resulting network) and the curing conditions. The shape-memory behaviour was investigated with bending tests. Recovery times of less than one second were observed in water depending on the temperature, and a linear correlation of the recovery time with cross-linking density and molecular weight of PCL network precursor was observed.