Research On The Influence Of Temperature And Polarity On The Molecular Self-assembly Of 4-vinylbenzoic Acid Onto Magnetic Nanoparticles Of Fe₃O₄

In this paper,the preparation of single layer oleic acid coated Fe3O4 magnetic nanoparticles(Fe3O4@OA)was studied.In the double distilled water system,4-vinylbenzoic acid was used as the monomer to obtain polymer at 50 ? as well as the best conditions for the preparation of magnetic nanoparticles with carboxyl(Fe3O4@OA-COOH).Then,under the best conditions,three solvents with different polarity were selected and the influences of mass of monomer and polarity of solvents on the process of self-assembly were studied.The experiments of TGA and conductivity titration were used to characterize the carboxyl content and the morphologies of Fe3O4@OA-COOH were taken by transmission electron microscopy(TEM).Finally,Fe3O4@OA-COOH was applied to the adsorption of bovine albumin.Firstly,the co-precipitation reaction was used to prepare Fe3O4 magnetic nanoparticles and oleic acid was used as the surface modifier to obtain Fe3O4@OA.After that,4-vinylbenzoic acid was used as the amphiphilic monomer,by self-assembly process and in-situ polymerization,to prepare Fe3O4@OA-COOH.Then in the double distilled water system,the experiments were performed in order to optimize the process.The affection of different conditions was analyzed by weight loss of the nanoparticles using TGA.The results showed that under the in-situ polymerization at 50 ? and double distilled water system the most excellent conditions were as follows:self-assembly temperature was 30 ?,self-assembly and in-situ polymerization time was 2 h and 3 h respectively.Thirdly under the best conditions,the influences of mass of monomer and polarity of solvents on the process of self-assembly were studied.The results showed that when masses of the monomer were less than 30 mg,more amounts of the coated polymers were obtained under solvent with bigger polarity.When masses of the monomer were more than 30 mg,the amounts of the coated polymers were independent to the solvents.The results of TEM showed that Fe3O4@OA-COOH had the core-shell structure with a single layer coated polymer on its surface.And the TGA results under the double distilled water system conformed to Langmuir adsorption.Finally,in the application of bovine serum albumin(BSA)adsorption,Fe3O4@OA-COOH had the maximum adsorption capacity to BSA which was up to 130.03 mg/g when the pH,the initial concentration of BSA and the time of adsorption was 5.0,1 mg/mL and 2 h respectively.