Self-assembly Synthesis and Properties of Microencapsulated <i>n</i>-Tetradecane Phase Change Materials with a Calcium Carbonate Shell for Cold Energy Storage

Abstract

Sodium dodecyl sulfate (SDS) and alkylphenol polyoxyethylene ether (OP-10) mixed templates, microencapsulated phase change materials (MEPCMs) with an n-tetradecane core, and calcium carbonate (CaCO3) shell were prepared by a self-assembly method. The effects of the core/shell mass ratio and the SDS/OP-10 mass ratio on the morphology and the phase change enthalpy of the synthesized MEPCMs were investigated by polarized optical microscope (POM) and differential scanning calorimetry (DSC), respectively. The structure and the thermal performance of the MEPCMs were systematically characterized by the method of Fourier transform infrared spectroscopy (FT-IR), an X-ray diffractometer (XRD), a scanning electron microscope and energy dispersive spectrometer (SEM-EDS), thermogravimetric analysis (TG), and a thermal constants analyzer. The results demonstrated that the self-assembly technique with SDS/OP-10 mixed templates could be successfully applied for the synthesis of n-tetradecane@CaCO3 MEPCMs with an encapsulation efficiency of 25.86%, and the calcium carbonate shell was the mixture of vaterite and calcite. The synthesized MEPCMs possessed nearly spherical morphology with a mean diameter of 5.0 μm, a latent heat capacity of 58.54 kJ/kg, and excellent thermal conductivity (0.61 W/(m·K)) as well as good thermal stability, indicating that it has good application prospects in cold energy storage.