Poly(ε-caprolactone) networks with tunable thermoresponsive shape memory via a facile photo-initiated thiol–ene pathway

Abstract

Thermoresponsive shape memory poly(e-caprolactone) (PCL) networks with readily tunable properties are prepared exploiting the facile UV-initiated thiol–ene methodology. PCLs with multiple pendant double bonds at both chain ends are used to cross-link with multi-thiol compounds via photo-initiated thiol–ene reactions. Mechanical and shape memory properties can be altered through changes in the number of alkene side groups at the PCL chain termini and thiol cross-linker structure. In parallel with structural investigation by spectroscopic techniques, the relationships between the composition and material properties are investigated. The PCL thermoset materials exhibit excellent thermoresponsive shape memory performance by changing the operation temperature below or above the melting temperature of crystalline PCL segments, which varies in the range of 34–40 °C, and the highest shape retention and recovery ratios can reach 98–100%.