Construction of multifunctional surface to fabricate wood-derived cellulose electrothermal composites with flame retardant and hydrophobic performance for harsh operating conditions

As a renewable resources, wood is limited to functional applications due to its defects of moisture deformation, water swelling, and flammability. At present, wood-derived cellulose electrothermal composites has excellent Joule heating performance, but it faces the dilemma of limited operating environment. To this end, multiwall carbon nanotubes (MWCNTs) were deposited on the wood-derived cellulose skeleton (WCS) surface by multiple dipping-drying cycles to obtain electrothermal performance. Ammonium polyphosphate and trichloro (1 H,1 H,2 H,2 H-tridecafluoro-n-octyl) silane were then sequentially deposited on MWCNTs/WCS surface to obtain better flame retardant and hydrophobic performance. The resultant multifunctional MWCNTs/WCS (MMW) achieved an average surface temperature of 119.3 °C at 4.0 V and retaining repeatability under power ON/OFF cycles. The residue amount of MMW was increased by 105.6% and the heat release capacity was decreased by 92.9% compared with WCS, which exhibited an excellent flame retardancy. Moreover, MMW had a water contact angle of 145.6° and showed durable hydrophobicity in harsh operating conditions. It is believed that MMW with electrothermal, flame retardant, and hydrophobic properties has promising applications in thermal therapy, aircraft deicing, indoor heating, and smart electronic wallpaper.