Superhydrophobic PTFE film for passive dew water harvesting via roll-to-roll manufacturing

Overview

This solution offers a passive dew water harvesting technology based on superhydrophobic polytetrafluoroethylene (PTFE) films with engineered surface morphologies. Designed for regions facing water scarcity, the films collect atmospheric moisture without any energy input. Each square meter of film is estimated to cost approximately $20 to install and can passively collect over 1 liter of dew water per night, translating to 50,000–100,000 gallons of clean water annually per installation. The technology provides a low-cost, scalable approach to portable water production suitable for deployment across diverse climates and geographies.

Technical specifications

• Superhydrophobic PTFE surface: Engineered microstructures achieve contact angles exceeding 150 degrees, enabling rapid water droplet removal.
• Dual droplet motion modes: The film supports both out-of-plane jumping and in-plane sweeping of condensed droplets, which minimizes evaporation losses and maximizes collection efficiency.
• Roll-to-roll (R2R) fabrication: Uses a microstructured mold in a continuous manufacturing process, enabling compact, customizable, and cost-effective production.
• Mold fabrication approach: Hot-embossed PMMA using an AAO (anodic aluminum oxide) mold with an aspect ratio of 2 has been validated to produce comparable surface morphologies.
• Material basis: Builds on prior research comparing silicon, black silicon, and PTFE-coated black silicon panels, with PTFE selected for its superior instant water removal capability.
• Scalable form factor: Sample films of 10 cm × 10 cm are used for testing, with the R2R process designed for large-scale production.

Technology readiness level

The technology is at an early-to-mid stage of development. Proof-of-concept validation has been completed, confirming that 1 square meter of PTFE-coated black silicon panel can passively collect more than 1 liter of dew water overnight. Surface morphology fabrication via hot embossing has been demonstrated, and contact angles above 150 degrees have been achieved. Next steps include fabricating sample PTFE films with varied surface morphologies, optimizing microstructures for maximum dew collection efficiency, and designing a lab-scale roll-to-roll system. The proof-of-concept research is expected to take approximately 6 months to complete. The team is seeking partners to support field tests, fund materials and supplies, and cover key personnel costs.