SLA printing of POSS-containing, bio-based composites with low dielectric constant and shape-memory function

Improving sustainability and functionality of resins is important for the development of 3D printing technologies. This work demonstrates a novel bio-based and low dielectric resin containing polyhedral oligomeric silses-quioxane (POSS) for stereolithography (SLA) printing to fabricate sensors and shape memory materials with complex geometry. Epoxidized soybean oil (ESO) and methacrylic acid are used to synthesize a biobased methacrylate resin (MESO) via a ring-opening reaction, followed by incorporation of POSS into polymer matrix. In general, the viscosity of POSS/MESO composite resins is in the range of 0.40-0.58 Pa s, making them viable for SLA printing designs. With the addition of 5 wt% POSS, POSS/MESO composites can exhibit excellent me-chanical properties, including tensile strength (18.9 MPa), elongation at break (19.8%), and toughness (399.2 MJ/m3). Furthermore, these materials have a very low dielectric constant of 2.97 at 1 MHz, which is desired for microelectronic applications to overcome signal delay and energy loss. In addition, presence of permanent and reversible networks formed by MESO and POSS endows the POSS/MESO composites with good shape memory property. The application demonstrators include fabrication of flexible interdigital electrode sensors and temperature-responsive sensors. Overall, this work provides great potential opportunities to design the bio-based functional sensor with on-demand control over structures by SLA printing.