Ultralight, Heat-Insulated, and Tough PVA Hydrogel Hybridized with SiO2 @cellulose Nanoclaws Aerogel via the Synergy of Hydrophilic and Hydrophobic Interfacial Interactions

Abstract

Lightweight porous hydrogels provide a worldwide scope for functional soft mateirals. However, most porous hydrogels have weak mechanical strength, high density (>1 g cm^-3 ), and high heat absorption due to weak interfacial interactions and high solvent fill rates, which severely limit their application in wearable soft-electronic devices. Herein, an effective hybrid hydrogel-aerogel strategy to assemble ultralight, heat-insulated, and tough polyvinyl alcohol (PVA)/SiO₂ @cellulose nanoclaws (CNCWs) hydrogels (PSCG) via strong interfacial interactions with hydrogen bonding and hydrophobic interaction is demonstrated. The resultant PSCG has an interesting hierarchical porous structure from bubble template (≈100 µm), PVA hydrogels networks introduced by ice crystals (≈10 µm), and hybrid SiO₂ aerogels (<50 nm), respectively. PSCG shows unprecedented low density (0.27 g cm^-3 ), high tensile strength (1.6 MPa) & compressive strength (1.5 MPa), excellent heat-insulated ability, and strain-sensitive conductivity. This lightweight porous and tough hydrogel with an ingenious design provides a new way for wearable soft-electronic devices.

Keywords: aerogel; heat-insulating; interfacial interactions; lightweight hydrogel; nanocellulose.