Near-infrared absorption photothermal conversion polyurethane film for energy storage

A series of near infrared absorption photothermal conversion polyurethane (PTPU) was synthesized with a cyanine dye to act as near infrared absorption component and polyethylene glycol 10,000 (PEG10000) to act as phase change material (PCM). The light resistant, pH dependence of dye and the effect of PEG10000 content on the properties of PTPU were investigated. The results showed that the cyanine dye had good light stability and was sensitive to pH, so a saturated solution of boric acid was added in the synthesis of PTPU to adjust its pH to 6 ~ 7. The crystalline degree of PTPU increased and its thermal stability decreased with the increasing of PEG10000 content; the light absorption of PTPU was mainly determined by the dye; the photothermal conversion efficiency and energy storage capability of PTPU increased with the increasing of PEG10000 and the PTPU can reach a higher temperature under illumination comparing to control polyurethane (PU); the PTPUs underwent a solid–solid phase change process and had excellent durability.