Elastomers

3D Printing of Double Network Granular Elastomers with Locally Varying Mechanical Properties

Elastomers are hydrophobic polymeric networks.  Due to their high polymer content, elastomers can attain a wide range of ultimate tensile strains and stiffnesses. Moreover, compared to hydrogels, their mechanical properties are less sensitive to moisture, such that elastomers can also be readily used in air. Unfortunately, the processing of elastomer that combine stiffness and toughness is limited to casting. Inspired by the superior mechanical properties of our double network granular hydrogel (DNGH) systems, we introduce double network granular elastomers (DNGEs) that can be 3D printed through direct ink writing. By tuning the composition of the elastomer microparticles and the 2^nd percolating network, DNGEs can attain a wide range of mechanical properties. We take advantage of the adjustable mechanical properties to produce an elastomeric finger that possesses locally varying mechanical properties such that it deforms in a pre-defined fashion.

This work is published in Advanced Materials and featured as a frontispiece.