Hierarchically nanostructured hybrid hydrogel for highly efficient solar steam generation

Physical Sciences : Materials and Compounds

Available for licensing


  • Guihua Yu, Ph.D. , Mechanical Engineering
  • Fei Zhao , University of Texas at Austin
  • Xingyi Zhou, B.S. , Mechanical Engineering

Background/unmet need

Fresh water shortage has become one of the greatest threats to the development of human civilization. Efficient solar desalination could provide a promising solution to produce clean water directly out of solar energy without extra energy input, particularly urgent for developing countries and remote areas without basic infrastructures.

Confining heat to air/water interface (i.e., the evaporating surface) is considered to be a highly promising approach to improve the efficiency of evaporation and the steam generation process. Steam generation through heat localization at the evaporation surface involves large optical absorption at the surface, photo-thermal (light-to-heat) conversion of incident light, confinement of heat to the evaporative surface, and transport of water from the bulk to the heat localization layer for efficient evaporation.

Over the past three years, various heat localization layers have been demonstrated to significantly improve the steam-generation efficiency compared to conventional bulk heating methods. However, most of these designs involve either energy (optical and/or thermal) concentration system or complex fabrication methods with poor prospects in terms of scalability. Thus, there is an immediate need for cost-effective and scalable water-heater that provides high steam-generation efficiency.

Invention Description

Researchers at The University of Texas at Austin have invented a novel interpenetrating structured hydrogel for water purification under one sun. In this unique design, the micro-gel which has broadband and efficient absorption under the sunlight can convert absorbed solar energy to thermal energy to achieve water purification steam generation. Meanwhile, the water delivery is controlled by the swelling of hydrogel, which can be tuned to make the rate of water supply close to that of steam generation, contributing to the heat localization to achieve high-efficient steam generation. Thus, the interpenetrating hydrogel could serve as a solar steam generation device with high efficiency.


  • The solar steam generation device does not need any energy (optical and/or thermal) concentration system under one sun.
  • The hydrogel exhibits excellent stability and efficiency in different water with harsh physical and chemical conditions.
  • The process is scalable and cost-effective.  


    Solar steam generation based on hydrogel for water purification with high efficiency under one sun

Market potential/applications

Drinkable water production and water purification.

Development Stage

Lab/bench prototype

IP Status

  • 1 U.S. patent application filed

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