Study On The Rheological Properties And Reaction Characteristic Of Photosensitive Viscoelastic Micelle Systems

In this paper, the micellization of cetyl trimethylammonium bromide (CTAB) and trans-chloro cinnamic (trans-CICA), including trans-para-chloro cinnamic acid (trans-pCICA),trans-meta-chloro cinnamic acid(trans-mCICA), and/trans-ortho-chloro cinnamic acid (trαns-oCICA) was studied. Viscosities of micellar systems and trans-CICA’s lowering effect on surface tension of the solution were investigated. Photorheological properties of CTAB/trans-CICA micellar systems before and after UV irradiation were studied and the rheological dynamics equation was established. Main conclusions were made as follows:1) The viscoelastic micelle systems could be formed by CTAB and trans-CICA in certain conditions. Relative viscosity of CTAB//trans-CICA micellar systems appeared a peak value when the molar ratio of CTAB to trans-CICA was about1.2. The position of chlorine atom substituent affect the viscosity of micellar systems at the same molar ratio, and the relative viscosity of trans-pCICA mixed with CTAB was maximum. Surface tension and cmc of CTAB solution could be reduced by appending propriety trans-CICA, and trans-pCICA has the strongest ability to reduce surface tension, trans-mCICA followed, trans-oCICA weakest, which indicating trans-CICA is a new type of counter-ion.2) The ultraviolet spectrum showed absorption peaks of trans-pCICA Itrans-oCICA from273nm move to267nm after UV irradiation, which confirmed that trans-CICA could isomerize to cis-CICA upon UV irradiation. Relative viscosity reduction percentage of CTAB/trans-CICA systems was related to concentration and proportion of CTAB and trans-CICA after UV irradiation. The solution viscosity could decrease by more than40%when CTAB/trans-pClCA(8mM/7mM). The position of chlorine substituent group affect the photosensitive properties of micellar systems, and the photosensitive properties of trαns-pCICA mixed with CTAB was strongest. The relative viscosity and concentration of trαns-pCICA of micellar systems both decreased with the increase of UV irradiation time. The established rheological kinetic equation could well describe the relationship between relative viscosity of micelle systems and conversion of trans-CICA.3) CTAB/trans-CICA micellar systems possessed typical shear-thining property, good visco-elasticity and thixotropy. The position of chlorine atom substituent affect the photorheology of micellar systems, and the visco-elasticity of trans-pCICA mixed with CTAB was strongest. The micellar systems showed obvious photorheological property in reducing viscoelasticity and thixotropy after UV irradiation. The flow curves before and after UV irradiation could be described by non-linear co-rotational Jeffreys model correctly, the calculated values are in good agreement with experimental data. The results show CTAB/trans-CICA micellar system is novel photorheological system. The studies in this paper provide good basis for the rheology and reaction kinetics of photosensitive viscoelastic micellar systems.