Dopamine-modified bacterial cellulose aerogel materials with photothermal conversion properties for efficient solar water evaporation

Bacterial cellulose-based aerogel materials exhibit a broad application potential in the field of water evaporation due to their unique nanostructures and physicochemical properties, such as good biocompatibility and degradability, especially their inherent porous structure that can effectively facilitate the water transport and evaporation process. However, the relatively simple molecular structure and the lack of sufficient cross-linking structure have resulted in poor mechanical properties, which, to a certain extent, has hindered its further application in this field. In this work, bacterial cellulose photothermal composite aerogel materials (PDA@BTCA@BCA) with excellent photothermal conversion functions were prepared by first chemically cross-linking bacterial cellulose nanofibers (BC) with butane tetracarboxylic acid (BTCA), and then polydopamine (PDA) was grown in situ on this basis. The results show that the modified material exhibits excellent mechanical properties. With 8 wt.% crosslinker and 0.5 wt.% PDA, the material achieves a compressive strength of 25.5 kPa at 80% strain. Moreover, it demonstrates outstanding elastic recovery, maintaining 93.2% recovery after 50 compression cycles at 50% strain. When irradiated with a 600-mW laser, the surface temperature of the material reaches [Formula: see text]C at a PDA concentration of only 0.5 wt.%. Additionally, the material achieves a photothermal evaporation rate of [Formula: see text]in pure water under one solar radiation. Therefore, the composite aerogel materials developed in this study have a wide range of potential applications for building sustainable, high-performance solar-driven photothermal interfacial evaporation systems.