Multimaterial 3D Printing of Highly Stretchable Silicone Elastomers

Abstract

3D printing of silicone elastomers with the direct ink writing (DIW) process has demonstrated great potential in areas as diverse as flexible electronics, medical devices, and soft robotics. However, most of current silicones are not printable because of their low viscosity and long curing time. The lack of systematic research on materials, devices, and processes during printing makes it a huge challenge to apply the DIW process more deeply and widely. In this report, aiming at the dilemmas in materials, devices, and processes, we proposed a comprehensive guide for printing highly stretchable silicone. Specifically, to improve the printability of silicone elastomers, nanosilica was added as a rheology modifier without sacrificing any stretching ability. To effectively control print speed and accuracy, a theoretical model was built and verified. With this strategy, silicone elastomers with different mechanical properties can all be printed and can realize infinite time and high speed printing (>25 mm/s) while maintaining accuracy. Here, superstretchable silicone that can be stretched to 2000% was printed for the first time, and complex structures can be printed with high quality. For further demonstration, prosthetic nose, data glove capable of detecting fingers' movement, and artificial muscle that can lift objects were printed directly. We believe that this work could provide a guide for further work using the DIW process to print soft matters in a wide range of application scenarios.

3D Graphene Scaffolds for Skeletal Muscle Regeneration: Future Perspectives

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3D printing of multi-scalable structures via high penetration near-infrared photopolymerization

“…4a, b, which presents a solution to obtain core-shell liked coaxial filaments with multi-material characteristic. By applying NIR-induced photocuring, it could be imagined to rapidly fabricate multi-material filament for a better performance thus promise the manufacturing of functionalized objects or programmed structures through this technique 10,23,33,34 . Freestanding objects fabrication has drawn growing interests in additive manufacturing for the combination of features, which ensure the human beings of freely create objects like the story of "Shenbi Ma Liang" in beginning.…”

Progress in wearable electronics/photonics—Moving toward the era of artificial intelligence and internet of things

“…Although these traditional micro‐electro‐mechanical systems (MEMS) based sensors can achieve high‐precision measurement of continuous finger motions in 3D space, sensor‐wise they are rigid and complicated to be fabricated, thus limiting their applications in light and flexible wearable situations. Flexibility, stretchability and light‐weight of wearable electronics, as the key factors determining the comfort level of users and the portability of devices, have drawn tremendous attention across the world for developing finger/glove sensors with such characteristics 122‐125 . The common flexible strain sensors are normally based on resistive sensing 123,126‐137 or capacitive sensing, 138,139 whose output signals can dynamically respond to the variation of applied force or strain under continuous motions.…”