4D Printing of Shape Memory Polymers: A Concise Review of Photopolymerized Acrylate-Based Materials

This paper presents a concise review on 4D printing of shape memory polymers that focuses on the use of acrylate-based materials using photopolymerization. Stereolithography (SLA), Digital Light Processing (DLP), Inkjet Printing (IJP), and UV assisted Direct ink Writing (UV-DIW) are the photopolymerization printing techniques that uses acrylate-based materials. These acrylate-based feedstocks will be polymerized during printing by the presence of UV light to form shape memory polymers (SMPs). Acrylate-based SMPs will change their shape in response to heat, water, light, and pH. Demonstrated applications of these 4D printed acrylate-bases SMPs are in biomedical, soft robotics, flexible electronics, and structural materials. However, 4D printing is still in the early stage and there are a lot of challenges like enhancing mechanical properties, biocompatibility, limited kind of SMPs, high cost of 4D printing system, and many more that needs to be addressed before a viable product can be produced.