| Summary: | 碩士 === 中原大學 === 化學研究所 === 99 === In this study, we combine the amine-capped aniline trimer (ACAT) and 4,4’-(4,4’-Isopropylidene-diphenoxy)bis(phthalic anhydride) (BSAA) to prepare the Electroactive Polyimide (EPI), because EPI have electroacitve segment and imide structure, it is expected to integrate these advantages, such as ACAT redox and dopable properties and the nature of the polyimide of high heat resistance and strong mechanical properties, base on the above, we prepare EPI by various method to fabricate : (1) Membranes (2) Microspheres (3) Nanofibers, and applied in different field.
In the membrane system, using casting method to prepare electroactive polyimide membranes (EPI), which revealing advanced gas separation capability as well as mechanically and thermally enhanced properties. Polyaniline (PANI) and conventional non-electroactive PI (NEPI) membranes were also prepared for control experiments.
It should be noted that EPI membrane were found to reveal permselectivities () of O2/N2 13.54, which is ~1.96 and ~ 1.54-fold higher than that of NEPI and PANI, respectively, based on the investigation of gas permeability analysis (GPA). Upon doping with 1.0 M HCl, the pemselectivities of EPI for O2/N2 was found to be further increased to 16.63. Moreover, significant mechanically and thermally enhanced properties of as-prepared EPI membrane was also found as compared to that of NEPI and PANI membranes based on the studies of dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively.
In the microsphere system, electroactive polyimide microspheres (EPS) was successfully prepared by electrospraying technology and applied in the detection of ascorbic acid (AA). The particle size of EPS can be controlled by varying the concentration of spraying solution while the electrocatalysis oxidation properties can be influenced by the different particle sizes of EPS. A sensor constructed using EPSS (small particles)-modified electrode was found to show 3-fold and 1.3-fold higher electrocatalytic activity toward the oxidation of AA than those constructed using EPI thin film and EPSL (large particles), respectively.
In the nanofiber system, we have developed dopable porous electroactive polyimide nanofiber (EPF) non-woven mats by electrospun technology. The EPF shows both electrochemical redox activity and reversible dopability, simultaneously. The high surface area, small diameter, and porous nature of EPF give significantly better performance in sensitivity for chemical sensing of HCl or NH3 gas.
Finally, degree of electrochemical activity and dopable property can be tuned by varying the content of ACAT existed in as-prepared electro-spun EPF mats. After doping with perfluorooctanesulfonic acid (PFOS), water contact angle of EPF surface is increased from hydrophobicity of 133º to superhydrophobicity of 155º. It is interesting that the EPF mat undergoes a switchable process from superhydrophobicity to superhydrophilicity via doping with PFOS and de-doping with ammonium gas.
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