Laser-Assisted Direct Ink Writing for High-Fidelity Fabrication of Elastomeric Complex Structures

Polydimethylsiloxane (PDMS) is extensively applied in the 3D printing field due to its excellent biocompatibility, flexibility, and gas permeability. However, as a thermal curing material, its low strength before curing inevitably causes structural deformation during the printing process and deteriorates the shape accuracy. In this paper, an innovative method, the infrared laser-assisted direct ink writing (DIW) process, is developed to realize the in situ preheating and curing of silicone materials to improve the strength of PDMS filaments during processing. Therefore, the large-span spatial structure with high-fidelity morphology can be produced. First, the feasibility is validated that temperature ascension of the voxels arising from the irradiation energy of the infrared laser can accelerate the cross-linking reaction and realize the precuring of PDMS; then, the relationship between the parameters of laser irradiation and the processing performance of 3D printing is systematically investigated to find the optimization. Finally, experiments are conducted, including the single silicone filament, silicone foams, and complex 3D features. Their excellent structural preservation proves the proposed method is practical to fabricate the high-fidelity fabrication of complex structures such as large spans and thin wall features, which will help to broaden the 3D printing capabilities of silicone in the development of flexible electronics and soft robots.