| Conductive polymer membrane is a kind of novel functional membrane with special physical chemical properties, such as the ability to response to particular stimulations from the environment, as called 'intelligence'. It has very widely potential application prospects in many fields, such as functional memory, membrane separating, sensor, electric junctions et al.Among many configuration-conductive polymers, polythiophene is particularly worth of investigation for its favorable properties, such as good thermal stability,environment stability,certain high charge-storage ability,favorable electrical chemical performances and good gas separating performances. But until now,its application is limited for several defects as poor working abilities and poor mechanical performances.Based on the recognition of the basic properties of polythiophene(PTh) and host membrane, guiding by the principle of in-situ synthesis, the PTh composite membranes with favorable mechanical performances and improved micro-pore configuration was prepared through the chemical in-situ vapor phase polymerization, during which the thiophene(Th) polymerized in the pore of the host membrane.The suitable solvent was selected by experimental. Polyvinylidene Fluoride (PVDF) microporous membrane was selected as host membrane. FeCl3 was used as oxidant. The PTh/PVDF composite membrane was prepared under the condition of low pressure and low temperature. Three main factors that affect the chemical in-situ vapor phase polymerization of Th in PVDF microporous were investigated, such as soaking condition of host membrane, drying process and reaction time. The resulting membranes displayed different apparent morphology under different preparation conditions. The properties of the resulting composite membrane were measured, such as the apparent morpha, conducting ability, average aperture and gas-separation performance of carbon dioxide/oxygen. A summary was conducted to improve the preparation of PTh/PVDF composite membrane. The results of IR analysis showed that there were no strong interactions between PTh and PVDF host membrane. The conductivity of the PTh/PVDF composite membrane was in the range of 10-5～10-4S·cm-1, which indicated the composite membranes belong to semi-conduct materials. To further investigate the effects of the in-situ synthetic conditions on the configuration of PTh/PVDF composite membrane, the thickness of the PVDF host membrane and PTh/PVDF composite membrane were measured. The porosity was measured by the mass weight method The maxium pore size,average pore size and the pore size distribution were measured with the combination of bubble-point-pressure method and fluid-permeation method, comparison of several samples were also made. The results indicated as for the PTh/PVDF composite membranes prepared through the chemical in-situ vapor phase polymerization, the thickness and porosity of the PTh/PVDF composite membrane changed little when compared to the PVDF host membrane, but the maxium pore size and the average pore size sharply decreased, the range of the pore size distribution narrowed, the pore size distribution located in a narrow range. The polymeration amount of PTh in the membrane pores could be controlled through the controling of reaction time. By this way, the pore size and the pore size distribution could be efficiently controlled during preparation.To investigate the performance of membrane, the permeation performances of oxygen,nitrogen,carbon dioxide et al in the composite membrane were measured, the electrical chemical properties and photo-fluorescent performances were also investigated,the doping effects and the conductivities of the PTh/PVDF composite membrane were investigated. As the results indicated, the composite membrane showed a selective permeation performance for the carbon dioxide. After suitable doping, the conductivities of the composite membranes were apparently improved, reaching up to 0.1～1 S·cm-1. Besides, certain photo-fluorescent property and electrochemistry performance wer... |
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