Study On The Preparation And Performance Of Photochromic Nanofiber Membranes

Photochromic compounds have received extensive attention and research in many fields such as physics,chemistry,biology,and nanotechnology due to the reversible color changes during light irradiation.However,the light-induced ring-opening and ring-closure processes of photochromic compounds are extremely susceptible to the external environment such as oxygen,acid,alkali,polarity,et al.,and their photochromic efficiency is reduced.Introducing the photochromic compound into polymer matrix has several advantages such as photostability,photoreversibility,elimination of dye aggregation and undesirable negative photochromism.Therefore,it is particularly important to find suitable polymer matrix materials for photochromic compounds.The comb-like polymer poly(octadecyl acrylate)was selected as the polymer matrix material of the photochromic compound spiropyran in this paper.Herein,spiropyran is dissolved in octadecyl acrylate(SA).Sodium lauryl sulfate(SDS),hexadecane(HD)and benzoyl peroxide(BPO)as emulsifier,co-emulsifier and initiator to prepare photochromic nanoparticles.Then,the photochromic nanoparticles were ultrasonically dispersed in a mixed spinning solution of water-soluble polyvinyl alcohol(PVA)and polyethyleneimine(PEI),and reversible photochromic nanofiber membrane containing comb-like poly(octadecyl acrylate)nanoparticles was prepared by electrospinning technique.Here,glutaraldehyde(GA),which could occur a cross-linking reaction with PVA/PEI,is selected as a crosslinker to enhance water resistance and mechanical behavior of the NFM.In addition,we also studied minutely the effect of the length of the alkyl side chain of the polymer matrix on the photochromic properties of the spiropyran dye.In this paper,the surface morphology,chemical structure,water resistance,mechanical properties,and photochromic properties of photochromic nanoparticles and nanofiber membranes were systematically characterized by optical microscope(OM),field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),static water contact angle tester(WCA),fourier infrared spectrometer(FTIR),X-ray photoelectron spectrometer,universal stretchers and ultraviolet and visible spectrophotometer.