Four-dimensional printing of a novel acrylate-based shape memory polymer using digital light processing

Abstract

Shape memory polymers (SMPs), a type of promising smart materials, are gradually applied into digital light processing (DLP) technology to realize four-dimensional (4D) printing. However, there is still a great lack of shape memory photosensitive resins suitable for DLP. In this work, novel acrylate-based photosensitive resins designed for DLP are prepared to fabricate SMP parts with tert-Butyl acrylate/1, 6-hexanediol diacrylate (tBA/HDDA) networks. The influence of crosslinker concentration on the shape memory and mechanical properties is systematically investigated. The results show that the developed SMP with 10 wt% crosslinker can withstand 16 consecutive cycles and retain extremely high shape recovery ratio of 100% even after 14 cycles, the one with 20 wt% crosslinker possesses the best shape fixity ratio of over 96%, and the storage modulus can reach up to 1.48 × 103 MPa with 50 wt% crosslinker. Furthermore, these 4D printed SMPs only spends 7–13 s in the 180° shape recovery, indicating a good shape recovery rate. This work confirms that the designed SMPs have potential applications in many areas due to their excellent shape memory performance, and provides valuable guidance for the shape memory properties optimization of other SMPs.