Research Of The Amphiphilic Photosensitive Copolymer Self-assembly And Its Emulsification Properties

There are three part in this paper. Part one: a series of photosensitive of amphiphilic random copolymer P(St-co-VM-co-AA)(referred to PSVA) was prepared through free radical copolymerization with styrene (St), 7-(4-vinylbenzyloxyl)-4-methylcoumarin (VM) and acrylic acid (AA) as co-monomers. These copolymers were characterized by gel permeation chromatography (GPC), Fourier transform Infrared Spectroscopic (FTIR), Magnetic Resonance Spectrometer (1H-NMR) and Differential Scanning Calorimeter (DSC). The copolymer could self-assemble into steady spherical micelles in the selective solvent DMF /water with suitable initial copolymer concentration and water content. The results show that increased the quantity ratio of AA moieties made the CWC increased and the size of micelles decreased. Because of the photosensitivity, after photocrosslinked structure of micelles were more stability. Then we talked about the effect of pH on the zeta potential and diameter of polymer micelles before and after photocrosslinked. Amphiphilic random copolymer micelle can be used as particulate emulsifier. The results of experiments showed that increasing pH values can improve emulsifying properties of this system.Part two: using St and methacrylic acid 2-(dimethylamino) ethyl ester (DMAEMA) as co-monomer, another amphiphilic random copolymer P(St-co-DM) was synthesized, referred to PSDM. These copolymers were characterized by GPC and 1H-NMR. The PSVA anion micelles and PSDM cation micelles were prepared with copolymer PSVA and PSDM, respectively, via self-assembly method in selective solution (DMF/H2O). Complex micelles were generated by mixing the anion and cation micelles together. DLS and Zeta potential investigations show that the size and surface charge of the complex micelles vary with the mixing ratio of anion and cation micelles. Emulsions were prepared by equal volume toluene and water, using complex micelles of PSVA/PSDM as Pickering emulsifier, varying the mass ratio. Photographs of the vessels were taken with digital camera and droplet size were shown by light microscopy. Finally, a variety of complex micelles were prepared by controlling mass ratio of anion micelle and cation micelle. Compared to either single PSVA anion micelle or PSDM cation micelle,the emulsification of complex micelles PSVA/PSDM were increased, especially when w(PSDM) was 33.3%. And when w(PSDM) was 24.2%, Zeta potential of complex micelles solution was zero. Furthermore, cross-linked PSVA anion micelles (CL-PSVA) were obtained by photo-dimerization of the pendant coumarin groups in PSVA under UV irradiation. The emulsion produced by the complex micelles CL-PSVA/PSDM as emulsifiers showed even better stability upon standing. Part three: Using VM and DMAEMA as co-monomer, synthesis a photosensitive of amphiphilic random copolymer P(VM-co-DM), referred to PVDM. With hydrochloride(HCl) we got ionic photosensitive polymer and then self-assembly method in selective solution DMF/H2O, we got P(VM-co-DM+)(PVDM+) cation micelle solution, and then mixing with Hyaluronic acid (HA) anion micelle we had complex micelles solution. Useing the complex micelles PVDM+/HA as Pickering emulsifier, we found that compared to either single components,the emulsification of complex micelles were improved; when w(HA) =0%~25% in complex micelles solution, we got stability of oil in water emulsion; and when w(HA) =2%, the emulsifying properties was best.