LLNL Develops Novel, Fast-Curing Silicone Ink: A Game-Changer for Silicone 3D Printing

While 3D printing has been around for decades, silicone 3D printing technology is something relatively new. The material is compatible with photopolymerization and material extrusion, but there are relatively few manufacturers making silicone 3D printing solutions. That does not mean the material does not have attractive qualities: it is biocompatible, flexible and resilient. It is also used for a wide range of applications, like protective materials, biomedical devices, flexible electronics and more. Given the wide range of applications, it is no wonder that researchers are working on making the material more suitable for 3D printing. Now, scientists at the Lawrence Livermore National Laboratory (LLNL) have developed a novel silicone ink for 3D printing that promises to change the game.

The team’s new silicone ink is not only fast-curing, but also allows for prints that are bigger, taller, thinner and more porous than ever before. The key to the new material is that it is actually in two parts. Silicone inks have both a catalyst (which speeds up a chemical reaction) and a crosslinker (which chemically joins molecules together). When the catalyst and crosslinker mix, they slowly gel together to bind structures. So, the LLNL researchers separated the catalyst and crosslinker. Then, the two are mixed during the printing process, producing silicone structures by inline mixing and co-extruding both materials. After the ink passes through the nozzle, it rapidly becomes rigid, increasing its self-supportive capacity.

Two-part “fast cure” silicone-based ink for direct ink writing, mixes just before printing, sets quickly at room temp, allowing for longer print times, ensuring structures will not collapse or sag, even in complex shapes and configurations (Image credits: LLNL)

“Since the ink is kept separate, you don’t have to worry about the print time because it is not going to solidify in the syringes,” said Anna Güell Izard, a postdoc in the Materials Engineering Division (MED) and the paper’s first author. “It’s also sturdier because the layers are gelling as you’re printing, so your structure will not start sagging.”