Design and long-term anti-icing mechanism of superhydrophobic TPU coatings synergistically enhanced by modified carbon nanotubes and zinc oxide

In this study, a superhydrophobic anti-icing coating with a gradient cross-linking structure and low surface energy was constructed by using polyurethane (TPU) as the interfacial reinforcing phase, and through the synergistic effect of polydimethylsiloxane (PDMS)-modified multi-walled carbon nanotubes (MWCNT) and stearic acid-modified zinc oxide (SA-ZnO). The experimental results of TPU-13SZPC coating show that: the static contact angle of the composite coating reaches 158.6 ± 0.8°; the icing time of surface water droplets is delayed to 612 s at −15 ℃, which is 970 % higher than that of pure TPU. In addition, the coating maintained a contact angle > 150° after 30 times of sandpaper abrasion and 24 h of acid and alkali corrosion, demonstrating excellent mechanical and chemical stability. Mechanistic analysis revealed that molecular dynamics (MD) simulations demonstrated changes in the relative concentration of water molecules on the surfaces of different TPU-SZPC coatings, confirming the hydrophobic effects of varying TPU-SZPC ratios. The synergistic effects of micro-nano multi-level structures and photothermal performance significantly suppressed ice nucleation formation. Additionally, density functional theory (DFT) confirmed that PDMS-modified MWCNTs exhibit superior photothermal conversion performance. As the content of PDMS-modified multi-walled carbon nanotubes increases, the overall photothermal performance of the coating is enhanced. This study provides new insights for the development of long-lasting anti-icing/de-icing materials under extreme environmental conditions.