Fabrication of superhydrophobic photothermal conversion fabric via layer-by-layer assembly of carbon nanotubes

Photothermal conversion material that generates thermal energy from sunlight is expected to be a promising technology for harvesting and conversion of clean solar energy. However, its photothermal conversion will be affected due to the surface contamination by dirt in outdoor applications, which greatly reduces the solar energy absorption. Herein, a superhydrophobic photothermal conversion fabric was fabricated through layer-by-lay self-assembly of carbon nanotubes (CNTs) on the surface of fibers, and followed by post-treatment with polydimethylsiloxane (PDMS). The CNTs not only impart to the fabric high photothermal conversion capability, but also construct roughening structures on the fiber surface. Consequently, the as-prepared fabric could be rapidly heated to 89.8 °C under one sun (1 kW/m 2 ) irradiation, and showed excellent superhydrophobicity with contact angle 165° ± 0.9° and rolling angle 0.6° ± 0.2°. Meanwhile, the fabric possessed excellent stability to organic solvent, acid/alkali solutions, and UV irradiation. Importantly, the superhydrophobic self-cleaning property prevents the photothermal coating from contamination to guarantee the durability of the photothermal conversion efficiency. Graphic abstract