十水硫酸钠水合盐凝胶的制备及其表面张力调控OA

To address the demand for the refined development of ultra-thin flexible phase change materials(PCMs)for diverse application scenarios in the energy storage field,this study aims to solve the inherent defects of large supercooling degree,phase separation,and easy leakage of sodium sulfate decahydrate(SSD)-based PCMs,and break through the process bottlenecks of high surface tension,poor spreadability,and easy pore formation in the preparation of ultra-thin hydrogels.This study fabricated sodium polyacrylate/calcium alginate/sodium sulfate decahydrate(PAAS/CA/SSD)double-network hydrogels via an in-situ sol-gel method.The formulation optimization,performance regulation,and key ultra-thin molding technologies of SSD hydrated salt hydrogel materials,which can be widely used in thermal energy storage and cooling fields,were systematically investigated.The results show that the PA-10 sample with a PAAS content of 10%exhibits the optimal comprehensive performance,with a phase change temperature of 31.88℃,phase change enthalpy of 119.7 J/g,decomposition temperature of 88.81℃,decomposition enthalpy of 913.5 J/g,tensile strength of 0.29 MPa in crystalline state,and elongation at break of 16%.Its thermal conductivity remains above 0.82 W/(m·K).The sample possesses both rigidity and flexibility without leakage,which meets the material performance requirements of energy storage devices.Through the synergistic regulation of 1%sodium hexametaphosphate(SHMP)and 6%borax,the supercooling degree of SSD is reduced to nearly 0℃,which significantly improves the controllability of phase change and solves the core performance issue for the engineering application of the material.To tackle the molding difficulty of ultra-thin hydrated salts,DuPont FS-300 surfactant was introduced to regulate the surface tension,and the optimal dosage was experimentally determined as 1‰.The contact angle of the hydrogel on the silicone mold surface decreased from 111.1° to 42.2°,and ultra-thin hydrogels with a thickness of 1 mm,no pores,and uniform thickness were successfully prepared,breaking through the molding process bottleneck of ultra-thin phase change hydrogels.Performance tests demonstrate that the surfactant only slightly loosens the gel network;its mechanical properties are still superior to those of samples prepared by the traditional compression method,and the thermal properties are not significantly affected,with the phase change enthalpy and decomposition enthalpy basically stable.The phase change temperature and flexible characteristics of this ultra-thin SSD-based hydrated salt hydrogel material are suitable for energy storage scenarios such as human body thermal management,lithium-ion battery thermal management,and thermal runaway protection.It provides a new route for the lightweight and thinning development of inorganic hydrated salt medium-low temperature energy storage materials,and also offers experimental basis and technical support for the miniaturization and flexible design of energy storage devices as well as system operation optimization.