Preparation and properties of a polyurethane film based on novel photochromic spirooxazine chain extension

Abstract

A new type of photochromic spirooxazine (SO–OH) containing dihydroxyl structure was synthesized and introduced as a functional chain extender into the polyurethane system to prepare a smart photochromic polyurethane material. In comparison to conventional surface grafting and physical blending, the photochromic film developed in this paper displays more excellent properties. On the one hand, SO–OH has better stability and fatigue resistance. On the other hand, the mechanical properties and thermal stability of the polyurethane film are also improved. Interestingly, this method overcomes many problems faced by spirooxazine in practical applications since the addition amount of the photochromic substance is uniform and controllable. It is worth noting that in this study the molecular weight of the soft segment PTMG is also changed to study the structure and performance of SO–OH in different polyurethane systems. The results of the research prove that the polyurethane films bonded with SO–OH show a good response in terms of reversible switching wettability. In addition, the contact angle difference of the photochromic films before and after ultraviolet light irradiation can reach up to 8.6°. This method makes the photochromic films prepared in this study highly promising candidates for application in the fields of smart devices, light detection, biomedical materials, cell culture, and non-enzymatic desorption.