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Coated acrylic condenser achieves 85 % water recovery
Researchers have developed a scalable acrylic condenser coated with a PEG-PVA-silane hydrophilic film for photoelectrothermal water harvesting. The system achieves up to 85 % water recovery and maintains stable performance over multiple cycles, offering a route to sustainable freshwater supply.
Freshwater scarcity is a growing global challenge, driven by population growth, environmental pollution and climate change. Efficient condensation is critical to improving the performance of solar-driven desalination and water purification, particularly in arid regions. A recent study introduces a flexible and scalable photoelectrothermal vapour condensation system built on an acrylic substrate, a material that has not previously been explored as a condenser surface.
The authors deposited a superhydrophilic thin-film coating composed of polyethylene glycol (PEG-400), poly(vinyl alcohol) (PVA) and a hybrid silica anchoring layer derived from tetraethyl orthosilicate (TEOS) and 3-aminopropyltriethoxysilane (KH550) onto plasma-pretreated acrylic substrates. PVA acts as a binder that enables robust interfacial bonding between the inorganic silane network and the polymeric acrylic surface, overcoming the intrinsic lack of surface silanol groups on acrylic. The resulting surface promotes rapid droplet coalescence, continuous water film formation and efficient condensate transport.
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Water recovery and long-term stability
Condensation performance was evaluated in terms of water collection rate, vapour condensation efficiency, cyclic stability and long-term wettability. Under optimised conditions in a laboratory environment (17 to 24 °C and 16 to 22 % relative humidity), the coated acrylic condenser achieved a water recovery of up to 85 % without the need for an additional cooling system. The water recovery rate remained above 80 % over six operating cycles and during 12 h of continuous operation, indicating strong wettability stability and mechanical durability.
Scanning electron microscopy and Raman spectroscopy confirmed the formation and structural integrity of the PEG-PVA-SiOH coating. Under an electrical input of 6 W, the theoretical water collection rate reached 6.5 L m⁻² day⁻¹, suggesting practical potential for freshwater supply in small households. According to the authors, the flexible and durable coating concept offers a scalable strategy for freshwater harvesting from seawater and wastewater sources, aligned with the growing demand for sustainable water technologies.
Source: Hossain, M. N., Suh, Y. & Lee, S. J., Simple, scalable and flexible condenser for efficient water harvesting. Progress in Organic Coatings (2026). https://doi.org/10.1016/j.porgcoat.2026.110286
