N-Dodecanol nanocapsules with supramolecular lock shell layer for thermal energy storage

Abstract

It is still a big challenge to obtain shape-stabilized nanoencapsulated core-shell phase change materials (NC-PCMs) with the encapsulation ratio up to 90 wt% via surfactant-free method due to the lack of novel nanoencapsulation method and related mechanism. Herein, we for the first time report a novel supramolecular lock shell layer technique without surfactant to facilely prepare shape-stabilized NC-PCMs with the encapsulation ratio range of 70–90 wt%. To this aim, amphiphilic macromolecular nanoreactors with the particle size of ~15 nm were firstly synthesized. n-Dodecanol as the heat storage core was then self-assembled into the nanoreactors under ultrasonification. A thin layer of crosslinked acrylates copolymers was prepared by in-situ grafting polymerization to further stabilize the potentially leaked n-dodecanol. Crystalline structure, morphology, and thermal behavior of the resulting NC-PCMs were extensively investigated. Relevant results indicate that the obtained NC-PCMs fluids show excellent storage stability in the temperature range of −50 to 50 °C, benefiting from their small particle size (60–90 nm) and intense supramolecular interactions between n-dodecanol and the prepared nanoreactors. Phase change temperature of the produced NC-PCMs is very close to that of neat n-dodecanol, no obvious supercooling phenomena have been detected for the produced NC-PCMs. The maximum encapsulation ratio, latent heat, and thermal conductivity of the shape-stabilized NC-PCMs approximate 90 wt%, 180 J g−1, and 0.1705 W m−1K−1, respectively, implying large potential application in the sectors of solar energy storage, waste heat management etc. The developed supramolecular lock-layer technique probably opens a new avenue in the search for NC-PCMs with ultrahigh mass content of core layer.