Bioinspired Silicone Rubber Foams With Adjustable Gradient Structures Induced via Temperature Fields

ABSTRACT The structure‐gradient silicone rubber foam (SRF) is an advanced bionic material with potential for applications in energy‐damping, triboelectric nanogenerators, and electromagnetic interference shielding. However, the production of SRFs with an adjustable gradient structure is still a significant challenge. Herein, a novel strategy combining in situ precuring of silicone rubber induced by gradient temperature fields with supercritical CO 2 foaming was developed to prepare SRFs with biomimetic gradient cellular structures. By regulating the unilateral heat source temperature and precuring time, SR samples with gradient curing degrees from 16.13% to 51.21% were achieved. Finally, a prospective structure‐gradient SRF with a cell size range of 24.10–182.80 μm was successfully prepared. The energy loss coefficient of gradient SRF can be reduced by 41.65% compared with that of uniform cellular structure foam with average cell size of 31.25 μm after 50 cycles. Gradient SRFs show significantly enhanced mechanical performance, recoverability, and elasticity. Besides, the underlying mechanism for generating this gradient cellular structure was clarified.