Polyurethanes tri- and tetra blocks functionalized with azo group: synthesis, characterization and evaluation of potential as photo-responsive materials

Abstract

Smart polymers exhibit responsiveness to specific stimuli, for example, to variations in temperature and pH, the incidence light, and others. In your most polymers having responsive characteristics are formed by sensitive segments these stimuli. Among the many types of polymeric materials, polyurethanes segment as allow the combination of blocks or segments with different characteristics allowing thus obtaining an intelligent material capable of responding to specific stimuli. At the case of segmented polyurethanes and photo-responsive a photosensitive compound (chromophore) is responsible for the response to light. Among the various types of chromophores, the azo compounds are most frequently used in the development of polymeric materials photo-responsive. The objective of this project is the synthesis of polyurethanes segmented triblock or tetrablock with photo-responsive macrodiol properties based on poly (ethylene glycol), poly (l-lactide) and poly (trimethylene carbonate) copolymer as a precursor and azo compounds (E)-2,2'-(diazene-1,2-diyl)diphenol; (E)-4-(phenyldiazenyl)benzene-1,3-diol and (E)-4,4'-(diazene-1,2-diyl)dianiline as photochromic compounds. Photo-responsive polymers find applications in optical data storage devices, linear and nonlinear optical materials and photonic devices in general. (AU)