Carbon nanotube-wrapped particles in sodium alginate hydrogels for enhanced solar evaporation and EMI shielding through tortuous channel

Abstract

The hydrogel evaporator has shown great potential in solar-driven seawater desalination. However, hydrogels often suffer from heat loss due to their high-water content. Therefore, achieving a balance between energy input and water supply in hydrogels remains a challenge. Herein, Carbon Nanotube-Wrapped Polyacrylamide (CP) particles were introduced into sodium alginate (SA) to prepare CPSA hydrogels with tortuous channels. The hydrogel achieves a balance between photothermal conversion and water supply by enhancing its photothermal performance and increasing the water transport distance. Under 1.0 sun irradiation, the CPSA hydrogel exhibits an evaporation rate of 1.97 kg m⁻² h⁻¹. Additionally, the CPSA hydrogel demonstrates excellent photocatalytic ability for wastewater treatment, such as methylene blue (MB) degradation. Moreover, the tortuous microstructure imparts the CPSA hydrogel (thickness: 6 mm) with an outstanding electromagnetic interference shielding effectiveness of 81.1 dB, primarily through absorption. This work provides new insights into the development of hydrogels for water-energy balance management and high electromagnetic wave shielding applications.