Flexible nanocomposite electrothermal films based on carbon nanotubes and waterborne polyurethane with high reliability, stretchability and low-temperature performance for wind turbine blade deicing

•The CNTs reinforce the WPU matrix to 3.7 and 135 times on their tensile strength and Young’s modulus.•The CNT/WPU film can start at −35 °C and work with a fast-repeated temperature cycle of −20 °C -+30 °C.•The packaged CNT/WPU film heaters can withstand 100,000 times 240° bending with resistance fluctuation of 3.17 %.•The repeated stretching of 2.0 % strain in the length direction had no impact on the film heaters’ temperature distribution.•The ice block even on a huge blade will drop down in 5 min with the heaters’ power density of 1600 W/m2.