This study focused on developing novel materials for 3D printed reverse thermo-responsive (RTR) and pH-sensitive structures, using the stereolithography (SLA) technique and demonstrated the double responsiveness of the constructs printed.

4D printing is a novel approach that enables dynamic functionality in ordinary static object. We used a methacrylated semicrystalline polymer to print objects exhibiting thermally triggered shape memory behaviour. By exploring various molecular weights, it was found that a methacrylated polycaprolactone polymer with a number average molecular weight of 10,000 g mol⁻¹ exhibited the best thermal and mechanical behaviour. The effect of dyes’ addition to the ink formulation on the photopolymerisation and on the printing processes was evaluated. The ink was utilised for demonstrating fabrication of dynamic jewellery and a shoe accessory by Digital Light Processing printing.