Photo/electro-thermal effect, flame retardant, multifunctional durable superhydrophobic sponge for all-weather recovery high viscosity crude oil and photothermal defrosting/deicing

Developing functional adsorption materials that efficiently adsorb high viscosity oil is crucial for solving oil spill accidents. Herein, low-density three-dimensional porous melamine sponge was used as the modified substrate. First, phytic acid is selected for modification to make it flame retardant. Then, polypyrrole (PPy) and hexadecyltrimethoxysilane (HDTMS) are modified on its surface through low-temperature polymerization and impregnation, ultimately obtaining a multifunctional durable superhydrophobic PA/PPy/HDTMS@MF (melamine foam) sponges with photo/electro-thermal effects and flame retardant. When the applied voltage is 10 V, the core temperature on the PA/PPy/HDTMS@MF sponge's surface rapidly increases from 26.4 °C to 134.6 °C within 80 s, and the sponge will not burn and be damaged. Under the irradiation of one sunlight (1 kW/m2), the surface core temperature can rapidly rise from 26.4 °C to 93 °C within 70 s. The superhydrophobic PA/PPy/HDTMS@MF sponge can all-weather absorb kinds of high viscosity crude oil and solid oils that are 18–27 times than its own mass, indicating that the prepared superhydrophobic sponge has excellent oil collection performance. And under one sunlight (1 kW/m2), after 10 cycles of desorption, the prepared superhydrophobic sponge can still absorb 26 times more crude oil than its own weight. In addition, PA/PPy/HDTMS@MF sponge also has the characteristic of photothermal defrosting and deicing, and the ice on its surface can begin to melt within 5 min under one sunlight (1 kW/m2). The melted water will not enter the inside of the sponge, effectively ensuring the utilization efficiency of photothermal effects. Based on the above advantages, the prepared photo/electro thermal conversion superhydrophobic sponge has excellent development prospects in the field of high viscosity oil adsorption and photothermal defrosting/deicing.