Developments in additive manufacturing have enabled the fabrication of soft machines that can safely interface with humans, creating new applications in soft robotics, wearable technologies, and haptics. However, designing custom inks for the 3D printing of soft materials with Young’s modulus less than 100 kPa remains a challenge due to highly coupled structure-property-process relationship in polymers. Here, we show a three-stage material chemistry process based on interpenetrating silicone double networks and ammonium bicarbonate particles that decouples the transient behavior during processing from the final properties of the material. Evaporation of ammonium bicarbonate particles at the final stage creates gaseous voids to produce foams with a low effective Young’s modulus in the 25 kPa −90 kPa range. Our photoirradiation-assisted direct ink writing system demonstrates the ability to maintain high resolution while enabling controlled loading of ammonium bicarbonate particles. The resultant multi-material possesses programmed porosity and related properties such as density, stiffness, Shore hardness, and ultimate strength in a monolithic object. Our multi-hardness synthetic hand and self-righting buoyant structure highlight these capabilities.

增材制造的发展使制造可以安全地与人类交互的软机器成为可能，在软机器人、可穿戴技术和触觉方面创造了新的应用。然而，由于聚合物中高度耦合的结构-性能-过程关系，为杨氏模量小于 100 kPa 的软材料的 3D 打印设计定制墨水仍然是一个挑战。在这里，我们展示了一种基于互穿有机硅双网络和碳酸氢铵颗粒的三阶段材料化学过程，该过程将加工过程中的瞬态行为与材料的最终特性分离。碳酸氢铵颗粒在最后阶段的蒸发会产生气态空隙，从而产生在 25 kPa -90 kPa 范围内具有低有效杨氏模量的泡沫。我们的光辐射辅助直接墨水书写系统展示了保持高分辨率的能力，同时能够控制碳酸氢铵颗粒的负载。由此产生的多材料具有程序化的孔隙率和相关特性，例如整体物体的密度、刚度、肖氏硬度和极限强度。我们的多硬度合成手和自恢复浮力结构突出了这些功能。