Multifunctional carbon nanotubes based hydrogel integrates photothermal water desalination, photothermal power generation, sensing, and flame retardancy, with a multi purpose and adjustable thermoelectric effect.

In this study, a novel carbon nanotube (CNT)-based acrylamide-acrylic acid copolymer gel (designated as GEL-CNT-ILS) was synthesized via radiation polymerization, incorporating multi-walled carbon nanotubes (MWCNTs) and ionic liquids (ILs). This work addresses key challenges in the development of multifunctional materials by integrating multiple functionalities into a single hydrogel system, overcoming the limitations of traditional materials that often excel in only one specific application. Benefiting from the Soret effect, the gel exhibited impressive thermoelectric conversion properties, with a high Seebeck coefficient ranging from 1.68 to 5.62 mV/K, demonstrating its potential for harvesting electricity from the temperature gradient between seawater and the material. The thermoelectric performance was found to be tunable by adjusting the absorbed dose during synthesis, providing a way to customize material properties for diverse applications. In addition, GEL-CNT-ILS exhibited excellent electrical conductivity (3.67 mS·cm), superior photothermal water evaporation efficiency (4.18 kg m·h), outstanding flame-retardant properties, and advanced sensing capabilities. These multifaceted characteristics make GEL-CNT-ILS an ideal material for applications in photothermal seawater desalination and other multifunctional systems.