Superelastic and Durable Hierarchical Porous Thermoplastic Polyurethane Monolith with Excellent Hydrophobicity for Highly Efficient Oil/Water Separation

Abstract

A superelastic hierarchical porous thermoplastic polyurethane (TPU) monolith with excellent hydrophobicity was facilely prepared by a thermally induced phase separation method with two cooling steps. The TPU monolith as an oil absorbent is capable to selectively absorb various oils/organic solvents from oil/water mixtures with high saturated absorption capacity (5.95–40.60 g g–1) and rapid absorption rate (achieving absorption equilibrium within 15 s). More importantly, the monolith exhibits remarkable superelasticity with large reversible compressibility and outstanding fatigue resistance (1500 cycles at 80% strain), allowing it to repetitively absorb oil via simple manual squeezing. Furthermore, the monolith possesses high tolerance and durability in a wide range of pH (2–12) and temperature (0–100 °C), even in a turbulent environment. The TPU monolith can also continuously absorb and remove oil/organic solvent from the water surface by a pump-assisted system. The above-mentioned advantages of a porous TPU monolith make it become a promising and sustainable candidate for water pollution treatment.