An Eco-friendly Method for Preparing Biomass Aerogels with Phase Change Material Emulsions and Graphene for Smart Thermal Management

Conventional methods for preparing phase change aerogels, such as melt impregnation, often lead to phase change materials (PCMs) heterogeneity and structural instability. To overcome these limitations, this study develops eco-friendly and stable PCM aerogels by dispersing cellulose nanocrystal-stabilised PCM emulsions into a chitosan solution, followed by vacuum freeze-drying. The preparation process is systematically optimised by investigating the effects of PCM concentration, drying time, and hydrogel mass on the phase change behaviour and physical properties of the aerogels. The optimal formulation achieves a high melting enthalpy of 185.9 J/g, corresponding to a 77.7% PCM encapsulation efficiency. To impart photo-thermal conversion capability, graphene is incorporated into the aerogel synthesis. Results demonstrate that higher graphene concentrations significantly enhance photo-thermal efficiency (achieving a maximum of 71.0%). We then evaluate the thermal management performance of these graphene/PCM emulsion infused aerogels across three scenarios: on simulated skin, in an outdoor environment, and within a simulated indoor room. The aerogels effectively regulate temperature, maintaining a comfortable microenvironment for extended periods by stabilising both surface and interior space temperatures. The good latent storage ability and photo-thermal conversion performance of the GCEC samples make them promising as wearable devices and construction materials that offer energy-efficient, warm, and comfortable microenvironments.