Structural Droplet-Based Electricity Generator Using Superhydrophobic Fiber-Reinforced Polymer for Smart Stormwater Management

Abstract

Automated and effective urban stormwater management (USM) is essential to address the increase in stormwater hazards due to climate change and urbanization. Although droplet-based electricity generators (DEGs) can help monitor dynamic environmental changes in real-time, they have limited long-term reliability. Herein, a superhydrophobic fiber-reinforced polymer-based DEG (S-FRP-DEG) is proposed for efficient USM. The fiber-reinforced polymer (FRP), composed of carbon fiber fabric, carbon fiber tow (CFT), glass fiber fabric, and epoxy, offers a high strength-to-weight ratio and corrosion resistance. A spray coating of polydimethylsiloxane and polytetrafluoroethylene particles on the FRP creates a superhydrophobic surface with a water contact angle of 167 degrees, enabling rapid droplet contact and separation over large areas. The coating accords self-cleaning ability and forms a negatively charged surface, enhancing energy harvesting performance. A closed circuit forms upon droplet impact on the superhydrophobic surface and contact with the adjacent CFT, generating up to 117.93 mW m-2 per droplet. Textured finish formed by peel ply during FRP manufacturing further improves energy generation and coating durability. The S-FRP-DEG can be configured with multiple CFTs to increase the energy storage rate, enabling LED operation and autonomous USM. This technology provides a practical solution for energy-efficient urban management and supports smart city development.