(602a) Photopolymerization-Based Extrusion for Fabrication of Profiled Parts and Growing Robots

Photopolymerization is widely used in additive manufacturing applications as a method for rapidly generating solid structure from a liquid resin. However, access to broader applications and higher throughputs is limited by the layer-by-layer nature and the finite build spaces of additive manufacturing processes. Therefore, we sought to expand the use of photopolymerization to a continuous fabrication technique known as extrusion. This talk will highlight the new extrusion technique, termed extrusion by self-lubricated interface photopolymerization (E-SLIP), which can continuously fabricate solid profiled polymer parts on-demand through simultaneous flow and selective photopolymerization of liquid thiol-ene monomers. We show that E-SLIP is enabled through the incorporation of poly(dimethylsiloxane)-block-poly(ethylene oxide) (PDMS-PEO) copolymer surfactant into the monomer solution, which forms a lubricant layer in-situ during extrusion. E-SLIP is capable of fabricating high-aspect ratio parts with a variety of profile geometries and with tunable mechanical properties. Moreover, E-SLIP can be exploited to produce soft robots that are capable of synthetic growth by a tip growing mechanism inspired by plants and fungi. These growing robots are able to grow at speeds of up to 12 cm/min and lengths up to 1.5 m and could execute a range of tasks, including exploration, burrowing, and traversing tortuous paths. These results establish E-SLIP as a potential platform for on-demand manufacturing, exploration, and sensing in a variety of environments.