Preparation Of Composites Based On Hydrogels And Polyaniline By Combining ATRP, Click Chemistry And Supercritical Carbon Dioxide Techniques

A series of hydrogel-polyaniline-based composites have been prepared by atom transfer radical polymerization (ATRP), click chemistry and supercritical carbon dioxide (scCO2) techniques, some following composite systems were selected to expound the unique advantages of ATRP and click chemistry in synthesis of amphiphilic stabilizer, on the other hand, scCO2 technique has also been developed in fabrication of some specialty materials, which indicated that scCO2 was a reaction media with outstanding functions, instead of an inert solvent.In the first chapter, the recent research achievements and development trends on hydrogels,polyaniline(PANI),scCO2,ATRP and click chemistry were described in great details, the feasibility and advantages of utilization of these techniques to synthesize hydrogel-PANI composites were also analyzed.In the second chapter, firstly, a sort of poly(vinyl acetate)-poly(2-(dimethylamino) ethyl methacrylate) block copolymer (PVAc-b-PDMAEMA) with controlled molecular weight and narrow molecular weight distribution from abundant, widely available, and inexpensive raw materials were synthesized. In the presence of the copolymer stabilizer, poly(2-hydroxyethyl methacrylate)-poly(glycidylmethacrylate)-poly(N-vinyl-2-pyrrolidone)(P(HEMA-GMA-NVP ))microspheres were synthesized by dispersion polymerization in scCO2 and these microspheres showed ideal particle size and narrow particle size distribution. Polyaniline-pentadecafluorooctanoic acid (PANI-PFOA) was also deposited on HMM hydrogel membranes which were prepared by microspheres mentioned above. Theoretic calculation result of the molar attraction constant revealed the formation process of PANI-PFOA micelle in scCO2. At the same time, the scCO2 preparation system was compared with that in water and isooctane media, the deposition using PFOA as dopant and dispersant in scCO2 could form a more uniform and compact PANI surface with fine fasciculate structure.In the third chapter, PANI nanoparticles were prepared in H2O/scCO2 inverse emulsion (denoted as PANI-SC) with bis(2-ethylhexyl)s-sodium sulfosuccinate (AOT) and polyether graft silicone oil (PeSi) as surfactants. Compared to PANI prepared in isooctane(denoted as PANI-CON), PANI-SC incorporated more AOT component, exhibited higher crystallinity, better dispersibility in ethanol and excellent conductivity. On the other hand, different polyaniline-montmorillonite (PANI-MMT) composites were prepared employing fluorinated-MMT and different chemical group modified MMT in H2O/CO2 inverse emulsion. The characterization results showed that aminated MMT and fluorinated-MMT could been completely exfoliated and dispersed in PANI matrix uniformly even with high MMT loading, the PANI-MMT composites revealed high thermal stability and excellent room temperature conductivity.In the fourth chapter, firstly, three-arm-like polymer quaternary ammonium salt with fluorinated side chains (PF-PHEMA)3-TAI-Q was synthesized, with this amphiphilic polymer as surfactant, chitosan (CS) grafted poly(2-acrylamide-2-methylpropanesulfonic acid) (PAMPS) was synthesized in H2O/CO2 inverse emulsion. The product CS-g-PAMPS exhibited high graft ratio and excellent water dispersion stability. CS-g-PAMPS hydrogels could be modified by adding PANI-MMT nanoparticles and showed more excellent conductivity, more remarkable mechanical strength, better gel swelling and higher swelling speed than pure CS and CS-g-PAMPS without PANI-MMT.In the fifth chapter, firstly, functionalized nylon fiber coated with camphorsulfonic acid-aniline (CSA-ANI) was prepared via click reaction, then CSA-PANI and p-perfluorous nonenoxybenzenesulfonate acid-polyaniline (PFNOBSA-PANI) were grafted on functionalized nylon fiber surface by in-situ polymerization in scCO2 with PFNOBSA as dopant and stabilizer. Carboxymethyl cellulose sodium salt (CMC) hydrogel layer could also be loaded on PANI-nylon composite fiber to be nylon-PANI-CMC three layers composite fiber.In the sixth chapter, firstly, four-branch-like gemini surfactant EDTA-4PFO-2Q with fluorinated side chains was prepared via click reaction to combine propynyl group modified ethylenediaminetetraacetic acid (EDTA) and azide group modified 1-Iodo-1H,1H,2H,2H-perfluorodecane (PFO), followed by quaternization. At the same time, poly(sulfonated styrene)-poly(perfluoroalkylethyl acrylate) block copolymer (PSS-b-PFOMA) was synthesized by ATRP technique. Self-assembly layer by layer process of PAMPS and poly(methacrylatoethyl dimethyl benzyl ammonium bromide) (PEMAQ) hydrogel membranes with EDTA-4PFO-2Q as emulsifier were performed on glass substrates (GS) in H2O/CO2 inverse emulsion. Finally, PANI-PSS-b-PFOMA was coated on glass GS-hydrogel membranes with PSS-b-PFOMA as stabilizer in scCO2 media, and superhydrophobic conducting composite functional substrates (CFS-sc) was obtained. Compared to CFS prepared in hexane media, CFS-sc revealed finer surface granule structure.In the seventh chapter, firstly, poly(methyl methacrylate)(PMMA) and poly(1H,1H,5H-octafluoropentyl methacrylate)(PFPMA) molecular chains were introduced ontoβ-cyclodextrin by ATRP random copolymerization, the productβ-CD-PMMA-r-PFPMA could be employed to stabilize dispersion polymerization of tert-butyl methacrylate (tBMA) scCO2 media and PtBMA weak gel microspheres were obtained in whichβ-CD-PMMA-r-PFPMA served as mobile crosslink "ring". The formation process and special function of weak gel microspheres were also analyzed, such as their superhydrophobic property, then PtBMA microspheres were converted into poly(acrylic acid) (PAAc) weak gel microspheres and acted as the core of composite microspheres which were coated by PANI performed in csCO2 media, finally the hollow PANI microspheres were obtained after corrosion of PAAc core.In the eighth chapter, firstly, a series of poly(tert-butyl acrylate) (Pg-PtBA) containing propargyl end group with different molecular weight were synthesized by ATRP, then were incorporated to azide group modified zinc oxide whisker (T-ZnOw-SiO2-N3) via click chemisty and the product T-ZnOw-SiO2·PtBA hybrid particles with high content grafted PtBA were obtained, which exihibited better thermal stability than pure PtBA. The hydrolyzed product T-ZnOw-SiO2·PANa also showed excellent water dispersibility and could serve as component added to enhance the mechanical strength of hydrogel matrix in next research stage.In the ninth chapter, firstly, copolymers of propargyl acrylate (PA) and VAc or DMAEMA, PVAc-r-PPA or PDMAEMA-r-PPA with a certain number of propargyl side groups were synthesized. At the same time, PVAc-N3 and PDMAMEA-N3 with azide end group were also prepared by degenerative chain transfer radical polymerization, and then comb-like copolymer PVAc-c-PDMAQ (PDMAQ was the quaternization product of PDMAEMA) or PDMAQ-c-PVAc were obtained via click chemistry to incorporate PVAc-r-PPA and PDMAMEA-N3 or PDMAEMA-r-PPA and PVAc-N3. PVAc-c-PDMAQ contained CO2-philic PVAc main chain and hydrophilic PDMAQ side chain, PDMAQ-c-PVAc contained hydrophilic PDMAQ main chain and CO2-philic PVAc side chain. With these copolymers as surfactants of CO2/H2O emulsion template, light weight and porous PAAc hydrogel were prepared, followed by immersion polymerization of aniline into this hydrogel in scCO2 media, the PANI-hydrogel functionally gradient materials could be obtained by controlling some reaction conditions, such as immersion time, CO2 pressure and aniline concentration.In the tenth chapter, major conclusions in whole dissertation were summarized, and the next research works were also prospected.