Study On The Rheology Of Novel Photosensitive Gemini Cationic Surfactant Micelle

In this paper,A new reactive cationic surfactant(EDAA)was synthesized with eruamidopropyl dimethylamine and epichlorohydrin,the new Gemini surfactant 25-HP-25 and the asymmetric Gemini surfactant 25-HP-21 were obtained by EDAA eruamidopropyl dimethylamine and oleoamidopropyl dimethylamine.The rheological properties of those novel cationic surfactant were studied.A new photothinning micelle composed of EDAA and photosensitive anti-ionic azobenz-4-benzoic acid(trans-ACA)was prepared.Another photothickening micelle composed of 25-HP-21 and trans-ACA was also prepared.The optimum conditions for them were studied.Then photorheological properties(rheological properties,microrheological properties)under different irradiation conditions were studied.Furthermore,the rheo-reactive kinetic equation EDAA/trans-ACA was established.SAXS was used to characterize the changes of the 25-HP-21/trans-ACA system before and after irradiations.Main conclusions were drawn as follows:1)A new cationic gemini surfactant(25-HP-25)was synthesized with eruamidopropyl dimethylamine and epichlorohydrin,and its solution is self-thickening.The viscosity of 25-HP-25(2wt%)solution was 6mpa.s,which exhibited well shear thinning properties and thixotropy with stress overshoot.2)EDAA/trans-ACA micelle system showed photothinning properties.After UV irradiation,the viscosity of photosensitive micellar system decreased by 60%,and the dynamic rheological response converted to be weakly elastic and viscous.Further,the curves of viscosity of EDAA/trans-ACA with UV irradiation time were achieved and the processes were described by rheo-kinetics equation under steady shear.3)25-HP-21/trans-ACA micelle system showed photothickening properties.After UV irradiation,the viscosity of photosensitive micellar system increased by 60%,and the dynamic rheological response converted to be strongly elastic and viscous,especially the elastic modulus.4)The micro-rheological properties of EDAA/trans-ACA and 25-HP-21/trans-ACA micellar systems were studied with microrheometer based on diffusing wave spectroscopy.The elasticity index(EI)of the systems that changing with different light irradiations showed corresponding changes.SAXS was used to characterize the changes of the 25-HP-21/trans-ACA system before and after irradiations.This paper is expected to enrich the research field of photosensitive fluids and provide a certain basis for the research on rheo-kinetics during light irradiation.