Research On Conductive Polymers And PTFE Composites Membrane

Conductive polymers have attracted great interests because of their excellent electrochemical reversible and environmental stability. However, the conductive polymers have been hampered to some extent due to their intractable nature, that is, its infusibility at melt processing temperature and poor solubility in common solvents. It can help to solve the process of conductive polymers with other supporting materials and achieve good performance composite materials. Polytetrafluoroethylene (PTFE) films possess excellent chemical stability, heat resistance and good mechanical properties, and make it better choice of supporting materials. This composite film with characteristics of both conductive polymers and PTFE can change and improve PTFE membrane performance and also broaden PTFE membrane application fields.In this study, the following jobs have been done:1. Superhydrophilic poly(tetrafluoroethylene) membranes modified with conductive polyaniline (Sewage treatment filtration membrane)The PTFE/PANI composite membranes with unchin-like morphology have been synthesized and immobilized on PTFE/Nafion membranes to render the PTFE surfaces superhydrophilic and electrically conductive. The PTFE/Nafion/PANI composite membranes have a good conductivity of 0.4 S/cm. The pristine PTFE membranes is hydrophobic in nature but when PANI is deposited on the PTFE membranes, they turn to superhydrophilic and the water contact angle is decreased from 153.7° to 0°. The experimental results show that the concentrations of ANI and p-TSA play an important role in forming the unchin-like polyaniline. Besides the excellent thermal and mechanical properties origining from the PTFE matrix, the advantages of the new composite materials lie in the convenience of the preparation process and the combination of the superhydrophilicity and the electrical activity, which promote their potential applications in disposable liquid/solid separation, heavy metal-ion sorption, biomolecule purification, chemical sensors, catalyst supports, and so on.2. Facile fabrication of poly(tetrafluoroethylene)/polyaniline/gold(PTFE/PANI/Au) composite membranes (membranes with catalytic function)At room temperature PTFE/PANI/Au composite membranes have been successful prepared with one step. The morphology and structure of the resulting composites were investigated by SEM images, FTIR and XRD spectra, respectively. The PTFE/PANI/Au composite membranes exhibit good catalytic activity for the catalytic reduction of p-nitrophenol by NaBH4. These composite membrane can be used repeatedly and have an obvious advantage of easy and convenient operation in the practical catalytic reaction system and have potential applications such as surface enhanced Raman scattering substrates, biosensors and so on.3. Facile fabrication of conducting and antibacterial bi-functional poly(tetrafluoro-ethylene)/polypyrrole/silver composite membranes (air filtration membrane with antibacterial function)To achieve conducting and antibacterial bi-functional PTFE composite membranes, two kinds of poly(tetrafluoroethylene)/polypyrrole/silver composite membranes have been prepared. One involves hydrophobic polypyrrole/silver composite with hollow capsules nanostructures immobilized on the surface of the PTFE membranes. The other is a type of composite membranes with polypyrrole/silver composite wholly packed the fibrils of the expand PTFE membrane to form core/shell nanocable structures. The composite membranes with high air permeability (43.21/dm2/min) and high hydrophobic (CA=133.59°) are promising candidates as air filter to realize the air cleaning with the anti-static and anti-microbial functions4. Room temperature synthesis of Ag/polypyrrole core-shell and hollow nanoparticlesTwo kinds of Ag/polypyrrole composite nanoparticles have been prepared via a one-step redox reaction between silver nitrate and pyrrole monomer at room temperature. One is Ag@polypyrrole core-shell nanoparticles that were synthesized by making use of synergic inducing effect of polyvinyl pyrrolidone and p-toluenesulfonic acid existing in aqueous solutions. The other is AgCl@Ag/ polypyrrole core-shell composite nanoparticles that were synthesized in the presence of HC1 using the in situ-formed AgC1 particles as the template. For the latter, its core can be easily removed via a simple dissolving procedure in sodium hyposulfite or ammonium chloride aqueous solutions, obtaining the Ag/polypyrrole hollow composite capsules. Experimental results suggest that the shell thickness and core diameter of the resulting composites can be controlled expediently by adjusting reaction time and concentration of pyrrole monomer.