Drop-Location-Insensitive Droplet-Based Electricity Generator Using Polydimethylsiloxane Slippery Covalently Attached...

Area of Science:

• Energy Harvesting
• Materials Science
• Surface Chemistry

Background:

• Droplet-based electricity generators (DEGs) harness water energy, but performance is limited by droplet behavior on surfaces.
• Superhydrophobic surfaces are used to promote droplet detachment, yet often suffer from inconsistent performance due to droplet bouncing and splitting.

Purpose of the Study:

• To develop a novel DEG platform with enhanced and stable energy harvesting capabilities.
• To overcome the limitations of conventional superhydrophobic surfaces in DEGs.
• To introduce a polydimethylsiloxane slippery covalently attached liquid (PDMS-SCAL) coating for improved droplet management.

Main Methods:

• A polydimethylsiloxane slippery covalently attached liquid (PDMS-SCAL) coating was developed and applied to a DEG platform.
• The performance of the PDMS-SCAL-DEG was evaluated under various conditions, including droplet height, incline angle, and drop location.
• Comparative studies were conducted against conventional superhydrophobic-DEGs.
• Durability was assessed through mechanical and chemical testing, as well as extended energy harvesting cycles and field testing.

Main Results:

• The PDMS-SCAL-DEG achieved a high open-circuit voltage of 162.2 ± 3.8 V.
• Significantly improved performance stability was observed across different droplet heights, incline angles, and drop locations, with only a ≤25% degradation 14.1 mm from the optimum point.
• In contrast, superhydrophobic-DEGs showed >92% degradation under similar conditions.
• The PDMS-SCAL-DEG maintained stable performance after 10,000 cycles and demonstrated reliability in real-world rainy environments.

Conclusions:

• The PDMS-SCAL coating effectively minimizes contact line pinning and droplet rebound, leading to superior energy harvesting performance.
• The developed DEG platform exhibits drop-location-insensitive characteristics, enhancing its practical applicability.
• The PDMS-SCAL-DEG demonstrates comprehensive durability and reliability, paving the way for expanded applications in water energy harvesting.