Preparation And Properties Of Poly(ionic Liquid)hydrogels

Stimuli-sensitive polymeric hydrogels have attracted considerable attention in the field of water purification and separation, active agent delivery vehicles(drugs,protein, and gene), catheters, contact lenses, artificial organs, sensors and actuators,because of it’s character of responding to various stimuli such as temperature, pH,specific ions, light, and electric fields. Among these applications, hydrogels have also been used as a template for the preparation and protection of metal nanoparticle. In this thesis, intelligent ionic hydrogels have been successfully synthesized, the application in catalysis has also been fully studied.ChapterⅠ: IntroductionThe synthesis, classification and application of the hydrogel were reviewed in this part.ChapterⅡ: The synthesis and application of P(AA-co-VBIm-Cl) hydrogelThe poly [acrylic acid(AA)-co-poly [1-methyl-3-(4-vinylbenzyl) imidazolium chloride(VBIm-Cl)] hydrogel was synthesized by free radical polymerization. The composition and morphology of the P(AA-co-VBIm-Cl) hydrogel were characterized by Fourier transform infrared spectra(FTIR) and scanning electron microscopy(SEM). Meanwhile, as-prepared P(AA-co-VBIm-Cl) hydrogel undergoes anion(PdCl62-) exchange for the metal loading(P(AA-co-VBIm-Cl)/Pd(0) catalyst).Formation and characterization of Pd nanoparticles(Pd NPs) within the P(AA-co-VBIm-Cl) hydrogel had been established using X-ray diffraction(XRD) and transmission electron microscope(TEM). The results showed that the average size of the Pd NPs within the hydrogel matrix were about 2-6 nm. The P(AA-co-VBIm-Cl)/Pd(0) catalyst showed higher catalytic activity in the catalytic reduction of nitro phenol.ChapterⅢ: The synthesis and characterization of P(NVA)/GO hydrogelA thermo-responsive, pH-responsive, and ionic hydrogel(P(NVA)/GO hydrogel)of poly [N-isopropylacrylamide(NIPAM)]-co-poly [1-methyl-3-(4-vinylbenzyl)imidazolium chloride(VBIm-Cl)]-co-poly [acrylic acid(AA)] with graphene oxide(GO) as another crosslinking agent was successfully synthesized. The hydrogel with aporous structure and quick responsiveness is obtained by adjusting the content of crosslinking agent, relative content of NIPAM to VBIm-Cl. The swelling behavior of P(NVA)/GO hydrogels under different pH, temperature and salting strength were also studied. The composition and morphology of the P(NVA)/GO hydrogel were characterized by various techniques. The result showed that the hydrogel had a well-defined and interconnected 3D porous network and uniform pore structure. The compression performance tests demonstrated that the incorporation of GO significantly enhanced the mechanical properties of P(NVA)/GO hydrogel.ChapterⅣ: The preparation of P(NVA)/GO/Pd(0) catalyst and application in organic reactionUsing the hydrogel of P(NVA)/GO as a template, P(NVA)/GO/Pd(0) catalyst had been prepared by anion exchange. The characterization of the P(NVA)/GO/Pd(0)catalyst had been established using XRD and TEM study. The results showed that the average size of the Pd NPs within the hydrogel matrix were about 1-3 nm. Catalytic activity of the as-synthesized P(NVA)/GO/Pd(0) catalyst was investigated by using the reduction of 4-nitrophenol with NaBH4 and C-C coupling reaction as model reaction. It was found that the design and synthesis of the P(NVA)/GO hydrogel led to the production of a highly active catalytic. Moreover, it can be separated easily after the reaction and reusing many times.