Durable Electro‐Photothermal Superhydrophobic Coatings Based on Liquid‐Like Functionalization of Nanoparticles: Improved Water Repellency and Droplet Rebound

Abstract This study reports on durable electro‐photo‐thermal superhydrophobic (SHS) coatings using nanomaterials functionalized with slippery liquid‐like brushes. Hydroxylated multi‐walled carbon nanotubes (CNTs) are functionalized with non‐reactive linear polydimethylsiloxane (LPDMS) by heating at 200 °C for 24 h, a method previously applied only to inorganic oxides. These are incorporated into an epoxy‐silicone hybrid resin and spray‐coated onto various substrates. Compared to traditional rigid alkyl‐functionalized CNTs, the LPDMS‐coated CNTs show superior water repellency, demonstrated by lower contact angle hysteresis (from 4.9° to 3.1°), reduced roll‐off angles (from 7.6° to 3.4°), and enhanced rebound behavior of impacting droplets (reduced contact times and increased number of rebounds). The coatings feature multiscale roughness and maintain superhydrophobicity after abrasion, outperforming surface‐textured coatings. The approach is compatible with both hydrophobic and hydrophilic resins, indicating broad applicability. While the anti‐icing performance is limited due to a temperature‐induced wetting transition, this is effectively addressed by electrothermal (up to 129.4 °C under 100 V) or photothermal (99.92% light absorption) surface heating, restoring the coating's superhydrophobicity. This is the first in‐depth, systematic comparison of nanocomposite coatings incorporating nanoadditives functionalized with liquid‐like PDMS brushes versus rigid alkyl brushes, evaluated in terms of water repellency, droplet rebound, and anti‐icing properties.