Tuning of thermal properties of sodium acetate trihydrate by blending with polymer and silver nanoparticles

The use of phase change materials (PCMs) is one of the pathways for the storage of temporarily excessive energy from natural sources (solar) and industry for use at a more suitable later time. One of the materials with a high energy storage density is sodium acetate trihydrate (SAT), on which several studies were conducted in order to solve phase segregation and supercooling problems, e.g. by adding polymers and nucleating agents. Here we investigate the effectiveness of adding a polymer blend of carboxymethyl cellulose (CMC) and silica gel to avoid phase segregation, and silver nanoparticles (AgNPs) as nucleating agent. The synthesis of silver nanoparticles was carried out by a green method in CMC as a way to ensure compatibility with SAT. The addition of AgNPs in higher concentrations to 0.5% reduces supercooling, and mixing silica gel with CMC to avoid segregation phase, yields an increment in the stability of the phase change behavior, during heating and cooling cycles. The latent heat release upon crystallization of the PCM was optimum for the mixture with 0.5% AgNPs, and for the highest amounts of CMC with respect to silica gel, with nearly 95% of latent heat recovery compared to pure SAT.