Stretch-Induced Ice-Shedding Protective Sheet by an Auxetic Skeletal Structure Embedded in an Organogel Matrix

Dealing with slush and ice buildup is common in northern climates. These contaminants can easily block important sensors for cars, such as cameras and LiDAR. Current anti-icing surfaces and deicing technologies are often not effective during the height of winter. This work describes the fabrication and testing of a protective composite sheet consisting of a slippery organogel matrix and an auxetic structure that both passively and actively sheds ice from the surface to protect these sensors. The organogel matrix excretes a slippery lubricating layer that prevents ice from building on the surface, and a uniaxially stretched auxetic structure creates an area mismatch between the surface of the sheet and the ice. The organogel matrix consists of a silicone elastomer precursor with silicone oil, providing optical transparency. The auxetic structure is 3d printed with a combination of Poly(dimethylsiloxane) (PDMS) with fumed silica added as a rheological modifier to provide additional strength to the structure. Image analysis reveals that the composite sheet has a staggering negative Poisson’s ratio of −0.58. In order to quantify the ice adhesion on the shield, home-built testing equipment is devised to assess the effectiveness of the protective sheets in removing ice built on the surface. A small critical shear stress to remove ice cubes from the sheet (<10 kpa) is achieved in various elastomer and organogel surfaces in static ice adhesion tests. However, active deice testing involving repetitive uniaxial stretching reveals that the auxetic property of the sheet is strictly necessary to remove ice buildup effectively. In conclusion, our composite sheets with a negative Poisson’s ratio with slippery, anti-icing surfaces are effective in removing ice buildup, suggesting their potential usage as a shield for optical sensors in autonomous vehicles and more.