Modeling and application of anisotropic hyperelasticity of PDMS polymers with surface patterns obtained by additive manufacturing technology.

Polydimethylsiloxane (PDMS) polymer has been widely used in the biomedical fields because of its bio-compatibility, being used as sensors, medical equipment and tissue implants. The present study aims to synthesize and characterize micro lane-type surface patterns of PDMS polymers and evaluate their effects on mechanical properties for various applications in the bio-engineering field. Fabrication of surface patterns is achieved using fused filament fabrication in additive manufacturing, and the mechanical properties of the polymer specimens with the surface patterns are measured using tensile test. The surface patterns are rotated at different angles and changed into different shapes to change the anisotropic material properties of the PDMS specimens. This is achieved by changing the raster angles and modifying the fused filament paths during the additive manufacturing process. In addition, the application of the printed pattern to medical soft robot is presented. Owing to the anisotropic material properties, in-plane and out-of-plane actuation can be realized by attaching polymer patches with different lane-type surface patterns. The results of this study support the implementation of additive manufacturing for the rapid manufacture of scalable structures with anisotropic material properties for various applications.