Bionic structure-based superhydrophobic TPU-TENG

To address the demand for flexible energy-harvesting surfaces for wearable electronics, this study develops a bioinspired superhydrophobic TPU-based triboelectric nanogenerator (TPU-TENG). The key feature of this work is the construction of a dual-mode TPU-TENG platform that can operate under two independent scenarios: harvesting biomechanical energy from human motion in the bending mode and harvesting raindrop kinetic energy in the rain mode. A tree-frog-inspired hexagonal microstructure was fabricated on polyether-type TPU through a template-assisted process, and SiO₂/CNT fillers were introduced to regulate surface roughness, wettability, and conductivity. The optimized surface exhibited a high water contact angle of 154° and a sliding angle below 10°, indicating excellent superhydrophobicity and low droplet adhesion. The TPU-TENG generated current outputs of approximately 0.7 μA in the raindrop mode and 800 μA in the bending mode. COMSOL Multiphysics 6.4 simulations and GBDT-assisted formulation analysis were used to support the interpretation of droplet dynamics and material optimization. This work provides a flexible superhydrophobic platform for wearable energy harvesting under different environmental and motion conditions.