Thermoregulating Lignin-Based Sustainable Nanocapsules Prepared by Miniemulsion–Solvent Evaporation

High Resolution Image Download MS PowerPoint Slide Lignin-based encapsulation of phase change materials (PCMs) offers a promising route to valorize lignocellulosic biomass in passive thermoregulating technologies. However, current lignin-based PCM capsules are mainly prepared by solvent exchange, where coupled lignin–PCM coprecipitation often limits encapsulation to fatty-acid PCMs. Here, we introduce a one-pot miniemulsion–solvent evaporation strategy to encapsulate hexadecane, a paraffinic PCM, within lignin nanoparticles. This approach combines nanodroplet confinement, which promotes PCM retention, with the progressive self-assembly of lignin at the PCM interface during solvent removal. Chloroform and ethyl acetate, the latter as a greener volatile solvent, were compared to elucidate how solvent-dependent lignin fractionation affects capsule formation and performance. The selected solvent governed the molecular features of the effective lignin fraction, yielding nanocapsules with distinct morphology, surface chemistry, energy storage efficiency, and thermoregulating response. When incorporated into felt fabrics, the lignin-encapsulated hexadecane significantly enhanced thermal buffering, proving this method as a suitable tool for designing biobased thermoregulating materials with practical energy-management potential.