Biomimetic Brushlike Slippery Coatings with Mechanically Robust, Self-Cleaning, and Icephobic Properties

In this work, a facile strategy was proposed to prepare a series of brushlike thermoplastic polyurethane (TPU) coatings with mechanically robust, self-cleaning, and icephobic performance. Through a simple multicomponent click reaction of thiolactone with a diamine compound and mono-ethenyl-terminated polydimethylsiloxane (mono-ethenyl-PDMS), a diol with amide groups and flexible PDMS was synthesized, and a novel TPU could be obtained productively by a reaction of isocyanate and diol. The unique chain structure endowed TPU films with ascendant self-stratifying properties. During solvent vapor annealing, flexible PDMS chains migrated and enriched to the surface while urethane linkages with a strong interaction tended to locate at the substrate. Based on this, TPU-PDMS films exhibited mechanically robust property, and the tensile strength value of TPU-PDMS-3 showed a sharp increase to 48.62 MPa. The resultant TPU-PDMS-10 coatings exhibited a water repellent behavior and possessed superior movability of droplet water, and also the dirt on it could be readily removed by rinsing with water without leaving any traces. Furthermore, three different criteria were used to characterize the icephobic performance. The coatings exhibited a significantly lower freezing point (approximately -27 °C) of supercooled water, longer delay-icing time, and less ice adhesion shear strength. Therefore, these novel brushlike TPU coatings have tremendous potential applications.