Fabrication of acanthosphere-like SiO2@Ag with designed angular tip silver shape for construction of superhydrophobic-electromagnetic shielding surface by imitating lotus leaf structure

• Acanthosphere-like SiO 2 @Ag Particles with Micro-Nano Structure were synthesized. • Coordination of N atoms of PVP K30 with silver leads to preferential growth of silver on SiO 2 particles surface. • The surface perfect reproduction of micro-nano rough structure of lotus leaf. • The superhydrophobic layer effectively protects its electromagnetic shielding properties. Superhydrophobic electromagnetic interference (EMI) shielding coating is of great significance to the safety and long-term service of all-weather outdoor equipment. However, it is still challenging to achieve long-term durability or other harsh service conditions. This work is based on the design of silver-based micro-nano structures, simulating the lotus leaf papilla structure, and then combining with nano-silver wires to obtain a superhydrophobic-electromagnetic shielding composite surface. SiO 2 @Ag particles with dual-scale structure are synthesized. The size of the SiO 2 particles is about 1.5 μm, and the size of silver particles, growing on the surface of SiO 2 particles in the shape of papilla, is about 50 nm, which means that the SiO 2 @Ag particles have a micro-nano dual-scale structure. Then SiO 2 @Ag particles were mixed with PDMS and uniformly sprayed onto substrates that have been pre-sprayed with Ag NWs/PDMS. A variety of instrument characterization methods were used to characterize its phase composition, composition, morphology, structure, water contact angle (WCA) and electromagnetic interference shielding effectiveness (EMI SE). The prepared Ag NWs/PDMS-SiO 2 @Ag/PDMS (AP-SP), imitating lotus leaf superhydrophobic-electromagnetic shielding composite surface, has a high WCA (168.3°) and superior EMI SE (51.7 dB). The product can withstand the erosion of acid and alkali while maintaining outstanding superhydrophobic performance, and the electromagnetic shielding performance can still reach 34 dB. The product also can withstand high temperatures 400°C without deterioration of super-hydrophobic- electromagnetic shielding performance.