Multimaterial\n3D Printing of Highly Stretchable Silicone\nElastomers

Abstract

3D printing of silicone\nelastomers with the direct ink writing\n(DIW) process has demonstrated great potential in areas as diverse\nas flexible electronics, medical devices, and soft robotics. However,\nmost of current silicones are not printable because of their low viscosity\nand long curing time. The lack of systematic research on materials,\ndevices, and processes during printing makes it a huge challenge to\napply the DIW process more deeply and widely. In this report, aiming\nat the dilemmas in materials, devices, and processes, we proposed\na comprehensive guide for printing highly stretchable silicone. Specifically,\nto improve the printability of silicone elastomers, nanosilica was\nadded as a rheology modifier without sacrificing any stretching ability.\nTo effectively control print speed and accuracy, a theoretical model\nwas built and verified. With this strategy, silicone elastomers with\ndifferent mechanical properties can all be printed and can realize\ninfinite time and high speed printing (>25 mm/s) while maintaining\naccuracy. Here, super-stretchable silicone that can be stretched to\n2000% was printed for the first time, and complex structures can be\nprinted with high quality. For further demonstration, prosthetic nose,\ndata glove capable of detecting fingers’ movement, and artificial\nmuscle that can lift objects were printed directly. We believe that\nthis work could provide a guide for further work using the DIW process\nto print soft matters in a wide range of application scenarios.