Youhong Nancy GUO, et al.
Hydrogel Airwell
Creating clean water from the air. Exploring super-absorbent hydrogels with Dr Youhong Nancy Guo
 Dr Youhong Nancy Guo, a postdoctoral researcher at MIT discusses her team's research on super-absorbent hydrogels. These can absorb water directly from the surrounding air. These can help create clean, drinkable water in arid areas.
Dr Guo's team's research article was ⁠Nature Communications Top 25 Chemistry and Materials Sciences Articles of 2022⁠
Dr Youhong Nancy Guo was chosen by ⁠⁠Forbes for their 30 under 30: Science 2023 list⁠⁠.
Youhong (Nancy) Guo

Polymers for a Sustainable Future  -- Solar-to-Thermal Energy Conversion & Utilization
Youhong develops hydrogel-based solar-driven water purification systems for efficient clean water production. The unique water states in polymer materials enable fast water evaporation from hydrogels with much lower energy demand. By integrating solar-absorbing materials with spatial distribution into hydrogels, She demonstrated high light-to-thermal conversion efficiency and ultrafast water evaporation under natural sunlight. She further designed the device systems to achieve high water collection efficiency. Check her publications below for more details:
Adv. Mater. 2020, 32, 1907061
Biomass-Derived Hybrid Hydrogel Evaporators for Cost-Effective Solar Water Purification
Abstract -- Solar vapor generation has presented great potential for wastewater treatment and seawater desalination with high energy conversion and utilization efficiency. However, technology gaps still exist for achieving a fast evaporation rate and high quality of water combined with low-cost deployment to provide a sustainable solar-driven water purification system. In this study, a naturally abundant biomass, konjac glucomannan, together with simple-to-fabricate iron-based metal-organic framework-derived photothermal nanoparticles is introduced into the polyvinyl alcohol networks, building hybrid hydrogel evaporators in a cost-effective fashion ($14.9 m−2 of total materials cost). With advantageous features of adequate water transport, effective water activation, and anti-salt-fouling function, the hybrid hydrogel evaporators achieve a high evaporation rate under one sun (1 kW m−2) at 3.2 kg m−2 h−1 out of wastewater with wide degrees of acidity and alkalinity (pH 2–14) and high-salinity seawater (up to 330 g kg−1). More notably, heavy metal ions are removed effectively by forming hydrogen and chelating bonds with excess hydroxyl groups in the hydrogel. It is anticipated that this study offers new possibilities for a deployable, cost-effective solar water purification system with assured water quality, especially for economically stressed communities.
Nat. Rev. Mater. 2020, 5, 388
ACS Nano 2019, 13, 7913
Synergistic Energy Nanoconfinement and Water Activation in Hydrogels for Efficient Solar Water Desalination
Precisely controlled distribution of energy in solar-to-thermal energy conversion systems could allow for enhanced energy utilization. Light-absorbing hydrogels provide a means for evaporating water by using solar energy, yet targeted delivery of solar thermal energy to power the water evaporation process remains challenging. Here, we report a light-absorbing sponge-like hydrogel (LASH) that is created by in situ gelation of a light-absorbing nanoparticle-modified polymer, leading to synergistic energy nanoconfinement and water activation. By experimental demonstration and theoretical simulation, the LASH presents record high vapor generation rates up to ∼3.6 kg m–2 h–1 and stable long-term performance under 1 sun (1 kW m–2) irradiation. We investigate the energy confinement at the polymer–nanoparticle interphases and the water activation enabled by polymer–water interaction to reveal the significance of such effects for high-rate solar vapor generation. The water vaporization enabled by LASHs can remove over 99.9% of salt ions in seawater through solar water desalination. The fundamental design principle, scalable fabrication route, and superior performance offer possibilities for portable solar water purification, industrial solar-powered water treatment, and other advanced solar thermal applications.
Acc. Chem. Res. 2019, 52, 3244
Hydrogels as an Emerging Material Platform for Solar Water Purification
...In this Account, we review our recent progress on hydrogel-based evaporators for solar water purification in terms of material selection, molecular engineering, and structural design. First, we introduce the unique water state in hydrogels consisting of free, intermediate, and bound water, of which intermediate water has a reduced energy demand for water evaporation. Then, we describe the design principles of hydrogel-based solar evaporators, where the polymeric networks are tailored to regulate the water state. The water state in hydrogels defines the vaporization behavior of water. Thus, the polymer networks of hydrogels can be architected to tune the water state and, hence, to further reduce the evaporation enthalpy of water. Armed with fundamental gelation chemistry, we discuss synthetic strategies of hydrogels for efficient vapor generation. By incorporating solar absorbers with hydrophilic polymer networks, solar energy is harvested and converted to heat energy, which can be in situ utilized to power the vaporization of contained water in the molecular meshes, and the solar absorbers having strong interaction with hydrogels guide the formation of microstructure to reduce the energy loss and ensure adequate water transport of evaporative water. Regulating the vaporizing fronts, engineering the surface of hydrogels has been focused to favor the evaporationof water to further enhance the solar-to-vapor efficiency. By using hydrophilic polymers as building blocks, the hydrogel-based solar evaporators have also been endowed with multiple functionalities, such as antifouling, permselectivity, and thermal responsiveness, to improve water collection and purification abilities. Taking advantages of these merits, hydrogels have emerged as a promising materials platform to enable efficient solar water purification under natural sunlight. This Account serves to promote future efforts toward practical purification systems using hydrogel-based solar evaporators to mitigate water scarcity by improving their performance, scalability, stability, and sustainability.
Energy Environ. Sci. 2018, 11,1985
A hydrogel-based antifouling solar evaporator for highly efficient water desalination
Solar desalination is a promising method for large-scale water purification by utilizing sustainable energy. However, current high-rate solar evaporation often relies on optical concentration due to the diffusion of natural sunlight, which leads to inadequate energy supply. Here we demonstrate a hydrogel-based solar evaporator that is capable of generating vapor at a high rate of ∼2.5 kg m−2 h−1 under one sun irradiation (1 kW m−2), among the best values reported in the literature. Such highly efficient solar evaporation is achieved by a hybrid hydrogel composed of a hydrophilic polymer framework (polyvinyl alcohol, PVA) and solar absorber (reduced graphene oxide, rGO), which has internal capillary channels. The PVA can greatly facilitate the water evaporation owing to the reduced water evaporation enthalpy in the hydrogel network. The rGO penetrating into the polymeric network enables efficient energy utilization. The capillary channels sustain an adequate water supply for continuous solar vapor generation at a high rate. This hydrogel-based solar evaporator also exhibits promising antifouling properties, enabling long-term water desalination without recycling. The high-efficiency hydrogel-based solar vapor generators open significant opportunities to enhance solar water evaporation performance and reduce the cost of solar desalination systems.

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Disclosed herein are water purifying networks. The networks efficiently absorb water and convert solar irradiation to heat, thereby evaporating absorbed water, which can be collected as purified water.
Youhong (Nancy) Guo
Materials for solar-powered water evaporation
Hydrogels and hydrogel-derived materials for energy and water sustainability
A hydrogel-based antifouling solar evaporator for highly efficient water desalination
Architecting highly hydratable polymer networks to tune the water state for solar water purification
Biomass‐derived hybrid hydrogel evaporators for cost‐effective solar water purification
Hydrogels as an emerging material platform for solar water purification
Synergistic energy nanoconfinement and water activation in hydrogels for efficient solar water desalination
Tailoring nanoscale surface topography of hydrogel for efficient solar vapor generation
Tailoring surface wetting states for ultrafast solar-driven water evaporation
Topology‐controlled hydration of polymer network in hydrogels for solar‐driven wastewater treatment
Nanostructured functional hydrogels as an emerging platform for advanced energy technologies
Carbon materials for solar water evaporation and desalination
Balancing the mechanical, electronic, and self-healing properties in conductive self-healing hydrogel for wearable sensor applications
Functional hydrogels for next-generation batteries and supercapacitors
Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments
Materials engineering for atmospheric water harvesting: progress and perspectives
Molecular engineering of hydrogels for rapid water disinfection and sustainable solar vapor generation
Polyzwitterionic hydrogels for efficient atmospheric water harvesting
Highly elastic interconnected porous hydrogels through self‐assembled templating for solar water purification
Engineering hydrogels for efficient solar desalination and water purification

US11834351 -- Composite hydrogel sponge and its preparation method and application, solar desalination device