Abstract
4D printing has steadily become an emerging area of advanced manufacturing research and has produced some
truly fantastic innovations. Previously we have demonstrated the 3D printing process based on PET-RAFT
polymerization, and its subsequent capability in the post-production modification of surface properties. In this
work, (1) we further optimized the PET-RAFT 3D printing formulation by replacing RAFT agent CDTPA
with BTPA and adjusting the monomers composition; (2) we also observed the photodegradation of the
photocatalysts EB and EY under 405nm light and the effects this has on 3D printing; (3) we then did successful
3D printing using a commercial 405nm DLP 3D printer, with an improved build speed of up to 2286 µm/hr;
(4) lastly, for the first time we have demonstrated a method for growth induced bending of a 3D printed strip,
where the growth on one side of the strip causes stress and the strip bends accordingly to reach a more
comfortable position.