Water Proof, Highly Tough and Fast Self-healing Polyurethane for Durable Electronic Skin

Stretchable electronic skin (E-skin) requires durable elastomeric matrix to serve in various conditions. Therefore, excel-lent and balanced properties in elasticity, water proof, toughness and self-healing are demanded. However, it is very difficult and often contradictory to optimize them at one time. Here, a polyurethane (BS-PU-3) containing polydisperse hard segment, hydrophobic soft segment and dynamic disulfide bond was prepared by one-pot synthesis. Unlike the normal two-pot reaction, BS-PU-3 obtained through one-pot method owned higher density of self-healing points along the main chain and faster self-healing speed, which reached 1.11 μm/min in a cut-through sample and recovered more than 93% of virgin mechanical properties in 6h at room temperature. Moreover, remarkable toughness of 27.5 MJ/m3 assures its durability as an E-skin matrix. Even with a 1 mm notch (half of the total width) on a standard dumbbell specimen, it could still bear the tensile strain up to 324% without any crack propagation....