Triboelectric nanogenerators (TENGs), as a new strategy for harvesting energy from nature, have attracted widespread attention in the field of water droplet energy capture. As a friction layer material, the solid–liquid
electrification phenomenon of coatings has been studied. However, little attention is paid to the influence of the surface wettability of the coating itself on the electrical signal of the droplet generator. In this study, alkyl/
phenyl pure silicone resin was utilized as a substitute for fluorine-containing polymer materials. This substitution not only mitigated the risk of environmental pollution from TENG friction materials but also resulted in varying wettability of the silicone resin coating through plasma and surface structure treatment. The droplet-based Double-electrode (D-TENG) and Single-electrode (S-TENG) coating-based triboelectric nanogenerators were fabricated. Through the integration of a high-speed camera and ammeter, the motion state of water droplets on
surfaces with different wettability closely correlates with their charged behavior. This correlation is utilized to observe the motion state of water droplets on hydrophilic-hydrophobic surfaces in four stages: contact,
spreading, contraction, and sliding. Under the double-electrode structure, as the water contact angle of the coating increased from 6.84◦ to 139.77◦, the short-circuit current initially increased and then decreased, peaking
at 466 µA when the contact angle was 98.48◦, representing a 677-fold increase from the initial 0.689 µA. In the single electrode structure, the short-circuit current increased from 2.66 nA to 700 nA, indicating a 263-fold increase. Studying the varied wettability of the surface of silicone resin coating aids in comprehending the application of the coating material in solid-liquid friction electrification for energy collection. Furthermore, it offers insight into selecting appropriate coating materials for friction coatings in future applications.