Incorporation of phase change materials into fibers for sustainable thermal energy storage

Abstract

Effective thermal modulation and storage are important aspects of efforts to improve energy efficiency across all sectors. Phase change materials (PCMs) can act as effective heat reservoirs due to the high latent heat associated with the phase change process (typically a solid−liquid transition). PCMs have been developed and integrated into various platforms such as building materials, gas sorbents/separators, and consumer products. Polymer fibers offer distinct benefits over other structures since they can be solution-processed and produced at enormous scales. In this work, we fabricate polymer fibers that possess high loadings (up to 80 wt %) of microencapsulated PCMs (μPCMs) to provide sufficient heat storage capacity. We focus on the solution spinning of cellulose due to its eco-friendly characteristics, low cost, and superior mechanical stability. We incorporate μPCMs into polymer dopes (e.g., cellulose acetate, polyethersulfone, cellulose), and μPCM-polymer fibers are then spun via solution-spinning processes. The thermal response behaviors of μPCM-polymer fibers were analyzed using differential scanning calorimetry (DSC), and no damage to μPCMs during the fiber spinning was observed. Additionally, no degradation of the PCM was observed after several freeze/melt cycles. The loading amount of μPCMs in fibers can be obtained up to 80 wt %, and around 95% of thermal storage capacities are retained in the fiber after the fabrication process. Dynamic mechanical analysis (DMA) reveals that there is a trade-off between the mechanical stability of μPCM-polymer fibers and loading amount of μPCMs; thus, optimization of the μPCM loading is required to meet application-specific mechanical stability. We expect that our engineered μPCM-polymer fibers can be applied to a smart thermal energy storage material that enables effective heat management. © 2021 American Chemical Society