Light-oriented 3D printing of 4'-pentyl-4-cyanobiphenyl (5CB) liquid crystal/photocurable resins and its in-situ enhancement of mechanical performance

Abstract

Abstract A new printing resin with excellent performance (PR-5CB) was prepared by mixing 4'-pentyl-4-cyanobiphenyl (5CB) with acrylic photosensitive resin. The combination of the stereo lithography appearance (SLA) technique and the PR-5CB photosensitive resin allows precise adjustment of the existing morphology of liquid crystals in the resin to further control the mechanical properties of the printed product. Upon the addition of 5CB, the light-driven orientation of 5CB drives other acrylate prepolymers to orient along the orientation direction of 5CB, so that the entire fixed 3D printing polymer becomes anisotropic as observed by polarized optical microscopy. By controlling the 3D printing lamination method, printing resolution, and 5CB content, the mechanical properties of the 3D printed products can be effectively improved. The rheological properties, mechanical properties, and heat resistance of the PR-5CB resins were systematically investigated. The tensile strength, elongation at break, flexural strength, impact strength, and storage strength of the PC-5CB-3//(25 µm) printed products were 121.2 MPa, 25.5%, 222.0 MPa, 11.09 kJ/m2, and 1702.3 MPa respectively; these values are 281%, 241%, 270%, 275%, and 186% of those of the commercial inks. The initial decomposition temperature of the printed sample of PR-5CB-3// (25 µm) was 298.5 °C and the maximum decomposition temperature was 423.5 °C, which were also higher than those of the commercial resins. The results of this study are significant for the development of light-cured 3D printing. The developed approach offers unlimited potential for achieving autonomous design of structures that cannot be achieved by current additive manufacturing processes.