Integrated Functionality of Photothermal Hydrogels and Membranes in Solar Water, Chemical, Mechanical, and Electrical Domains

Abstract Solar energy can be harnessed and converted into heat via the photothermal effect, which can then be utilized to drive many other reactions to produce important resources, such as water, fuel, electricity, and even mechanical actuation in a clean and sustainable manner. Hydrogels and membranes coupled with photothermal materials are particularly suitable for this purpose because they possess advantageous properties, such as porosity and adaptability. These properties allow for the introduction of diverse additives and functionalities, ensuring that photothermal systems can be customized for specific tasks, thereby enhancing their overall performance, functionality and versatility. This review aims to provide an overview of recent developments and the significance of employing photothermal hydrogels and membranes in multiple fields ranging from clean water, fuel production, electricity generation to mechanical actuation, followed by a discussion on key considerations in materials design and engineering. Finally, the review addresses the challenges and future directions of photothermal applications.