Fig. 1: Printing setup, material composition, and thermomechanical properties.
From: 4D printing through vat photopolymerization of two-stage UV-curable liquid crystal elastomers
a Schematic of the digital light processing (DLP) printing setup. b Chemical structures of precursor resins for the two-stage liquid crystal elastomer (LCE), including the diacrylate monomer 1,4-bis[4-(3-acryloyloxypropyloxy) benzoyloxy]−2-methylbenzene (RM257), the dithiol spacer 2,2’-(ethylenedioxy) diethanethiol (EDDET), the monomer glycidyl methacrylate (GMA), and the diamine crosslinker poly (propylene glycol) bis (2-aminopropyl ether) (D230). c As-printed LCE lattice structure and d its corresponding network schematic. e After being heated at 80 °C for 14 h, the lattice retains its programmed shape at room temperature. f Schematic of the LCE network structure after post-heating, highlighting the formation of the epoxy linkages. g The programmed LCE lattice fully recovers the as-printed shape at 100 °C. h Schematic of the network structure after shape recovery. i Storage modulus and tanδ of AE_6 specimen. Solid curves: before heating. Dashed curves: after heating. j Room-temperature stress-strain curve for AE_6 specimen before and after thermal treatment. k Summary of glass transition temperature (Tg) and l Young’s modulus of different LCE samples before and after thermal treatment. In k, l, each bar represents a single measurement (n = 1).
