Low Durometer, High Performance Silicones for Direct Ink Write

From a production perspective, 3D printing techniques such as Direct Ink Write (DIW) provide the opportunity to tailor the mechanical response of soft device architectures by enabling precise spatial control of their support structure. Mechanical response is further tailored via formulation control of the printed material. Formulation science is critical to the development of new DIW feedstocks as typical “inks” must exhibit low yield stress thixotropy to enable extrusion out of a nozzle and avoid post-extrusion flow to retain the resolution of the printed product; all while meeting the requisite performance of the final product. Low durometer silicones employed in soft device applications often suffer from low ultimate mechanical properties that prove detrimental to practical utility. To address the need for higher performance silicones for DIW, a new set of ca. 20 – 50 ShoreA silicone elastomers exhibiting ca. 7.5MPa ultimate tensile strength and ca. 400 – 1200% elongation at break are presented. Proof-of-concept prints demonstrate the potential for these new DIW silicones to find use as support material for soft device applications.<br/><br/>This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.