Polyurethane Foams Coated with Phosphorus-Doped Mesoporous Carbon for Flame-Retardant Triboelectric Nanogenerators

A phosphorus-doped mesoporous carbon (PMC)-filled coating was deposited on polyurethane foam (PUF) via a layer-by-layer assembly method. First, PMC was prepared from bio-sourced saccharose and phytic acid using mesoporous silica KIT-6 as a hard template. The coated PUF was then prepared by alternate dipping into a chitosan (CH) solution and dipping into an alginate-stabilized PMC (AL-PMC) aqueous dispersion. A few layers (three bilayers) of the CH/AL-PMC coating allowed the PUF to self-extinguish when exposed to a butane flame (≈1400 °C). Additionally, this coating layer enabled the foam to pass the UL-94 rating. Cone calorimetry revealed that this coating reduced the peak heat release rate, rate of smoke release, total smoke release, peak CO2 production rate, and peak CO production rate by 56, 48, 29, 35, and 35%, respectively. Using this foam, a flame retardant foam-based triboelectric nanogenerator (FRF-TENG) was fabricated. The FRF-TENG exhibited excellent energy harvesting performance, offering 158 V and 2.26 μA cm–2 open-circuit voltage and short-circuit current density, respectively. Furthermore, the FRF-TENG can be attached on a chair and serve as a self-powered sensor for the detection of back movement and sit-stand motion. This study may provide a promising potential for the design and fabrication of multifunctional smart foams.