Self-assembly of nanoencapsulated undecanoic acid on cotton fiber for thermoregulating textiles.

We herein report the preparation of phase change nanocapsules with undecanoic acid (UA) as the core and a styrene-butyl acrylate copolymer as the shell by miniemulsion polymerization using interfacial redox initiation. The morphology, particle size, thermal properties, and structure of the nanocapsules were characterized by transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. Further, the cotton fiber was dissolved in hydroxyl-functionalized ionic liquid 1-(3-chloro-2-hydroxypropyl)-3-methyl imidazolium chloride, and then the nanoencapsulated UA was immobilized on the cotton fiber by mixing the solution with the phase change nanocapsule emulsion. The desired thermoregulating fabrics were then recovered by vacuum suction filtration and drying, and their surface morphologies and thermoregulating properties were evaluated. The nanocapsules were found to be of a regular spherical shape with a diameter ranging from 90 to 110 nm, and they exhibit a phase change temperature of 29.3 °C. Finally, the prepared thermoregulating non-woven fabrics exhibited excellent thermal reliability, air permeability, and thermoregulating capability.