Anti-moisture, anti-bacterial cellulosic triboelectric materials enabled by hydroxyl coordination effect

Abstract

Owing to their low cost, customizability, and environmental stability, cellulosic triboelectric materials have emerged among polymer materials. However, the rich hydrogen bonding network inherent in cellulose limits its polarity and electron-donating ability, and charge dissipation caused by the hygroscopicity of the hydroxyl-rich groups limits its application as a triboelectric material. In this study, a more convenient, economical, and environmentally friendly "stent surgery" strategy was adopted. The wetting and swelling of fiber molecules allowed Cu (II) coordination with hydroxyl groups in nanocellulose. The coordination effect of cellulose hydroxyl groups weakens the intermolecular hydrogen bonding network, leading to an increase in the molecular dipole moment and the formation of new polar regions to regulate its space charge distribution, which significantly improved the electron-supplying capacity of the nanocellulose materials, and the maximum output power density increased by a factor of 2.78 (from 45 to 125 μW cm−2). Notably, the CNF-Cu (II) triboelectric material demonstrated excellent antimicrobial (>99%) and UV transmittance (<8%) as well as resistance to humidity interference, exhibiting only 5.9% voltage output loss at high humidity (90% RH). The design of this study provides new approaches for cellulose polarity modulation and energy harvesting adapted to harsh environments.