Preparation and properties of light-responsive liquid crystal poly(urethane-acrylate)composite films
When azobenzene compounds are irradiated with light of a specific wavelength,their molecular structure undergoes isomerization,transitioning from a more stable trans structure to a cis structure and this photoisomerization is reversible.Introducing azobenzene groups into polymer structures can endow polymer materials with photo induced deformation properties.In order to prepare multi light responsive materials with strong photo induced deformation ability and deformation recovery,the side-chain liquid crystalline poly(urethane-acrylate)(LCPUA)containing azobenzene groups was prepared through radical polymerization using 2,2'-azobis(2-methylpropionitrile)as an initiator,and was compounded with shape memory polyurethane(SMPU)made by self through electrospinning to prepare composite films.The effects of mass ratio of LCPUA to SMPU on the properties of compos-ite films were investigated.The results show that the thermal decomposition temperature of the side-chain LCPUA is above 250℃,indicating good thermal stability.The LCPUA has a wide liquid crystal range and exhibits UV response and visible light recovery properties in tetrahydrofuran solution,and the response time of ultraviolet light is 5 s.The mixed solution of LCPUA and SMPU also has the properties of UV-induced isomerization,and the composite film shows UV-induced deformation and visible light recovery properties.When the mass ratio of LCPUA to SMPU is 1∶2,the UV response time of the composite film is 10 s,which is faster than other systems and similar to that of the composite solution.The decrease of SMPU content reduces the deformation recovery ability of the composite film.
NETL
NSTL
万方数据
