Carbene-mediated covalent functionalisation of cellulose cotton fabric for durable photothermal superhydrophobic deicing

Cellulose cotton fabrics are renewable, flexible and porous, but their abundant hydroxyl groups make them prone to water uptake and icing in cold, humid environments. Here, a fluorine-free, carbene-mediated covalent interfacial strategy was developed to fabricate durable photothermal superhydrophobic cotton fabrics for solar-driven deicing. Hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) were deposited on one side of the fabric by vacuum-assisted filtration to form a photothermally active rough layer. Dodecyl-substituted bis(diaryldiazomethane) (ADDM) was then introduced and thermally activated at 120 °C, generating carbene intermediates that promoted covalent coupling between cellulose and MWCNTs-OH and simultaneously introduced hydrophobic alkyl chains, yielding a stable interfacial network. The resulting CNT-X-ADDM fabrics combined hierarchical micro/nanoscale roughness, low surface energy and broad solar absorption. CNT-4-ADDM showed a water contact angle of 165.5 ± 0.8°, a sliding angle of 1.2 ± 0.1°, a temperature rise of 64.4 ± 0.8 °C under 1 sun irradiation and ice detachment within about 30 s. Superhydrophobicity and photothermal deicing were retained after 200 tape-peeling cycles, 200 abrasion cycles and 50 soap-washing cycles. Under simulated complex icing conditions, photothermal interfacial heating rapidly weakened the mechanical interlocking between ice and the rough surface, enabling rapid ice removal and restoration of a dry superhydrophobic state. Air permeability, softness and breaking strength were also preserved. This work provides a covalent interfacial engineering route to durable photothermal deicing functionalisation of cellulose-based textiles.