Conductive Properties And Mechanism Of Various Polymers Doped With Carbon Nanotube Based Hybrid Nanoparticles

Polymers doped by carbon nanotubes (CNTs) with notably electrical, thermal, and mechanical properties have attracted tremendous attention in both academia and industry. Many researchers have centered on improving the dispersion of CNTs, to produce CNTs/polymer composites with high conductivity and low content of CNTs in the past years. Besides, finding new CNTs-based multi-component fillers would be a new way to achieve this goal.Our work could divide into three parts:1、Specifically, one-dimension (1D) hybrid nanotubes (MPPy) have been easily prepared by in-situ polymerization with appropriate ratio of pyrrole to MWNTs. MPANI nanoparticles were synthesized by one-step, in-situ polymerization of aniline in the presence of MWNT, with ammonium peroxidisulfate (APS) as the oxidant. As evidenced by X-ray photoelectron spectroscopy, the π-π interaction between MWNT and PANI supports enhances carrier mobility, which leads to high electrical conductivity of MWNT/PANI nanoparticles at low MWNT content. The highly ordered chain structure of PPy grown along the surface of MWNT might be responsible for the good performance of MPPy nanotubes as indicated by FESEM, X-ray photoelectron spectroscopy and Hall Effect Measurement System analysis. This order significantly promoted a more planar configuration of PPy, which would in favor of electrical transport between PPy and MWNT, and guaranteed high electrical conductivity of 1 D and MPPy hybrid nanotubes.2、Three matrixes including polyvinyl chloride (PVC), poly (methyl methacrylate) (PMMA) and polystyrene (PS) were separately mechanical blending with MPPy nanotubes. Three families of composites (MPPy/PVC, MPPy/PMMA, MPPy/PS) achieved electrical conductivity higher than 10-5 S/cm at 0.3 wt %,0.5 wt % and 1.2 wt % of MWNTs. The amounts of MWNTs were an order of magnitude lower compared to bare MWNTs used as fillers. We combined doping effect and tunneling distance to explore the conductive mechanism in three matrixes. The more potent doping effect and longer tunneling distance in MPPy/PVC families enabled sharp improvement of carrier concentration and therefore lower percolation threshold, compared to that of MPPy/PMMA and MPPy/PS families.3、Three matrices, polyvinyl chloride (PVC), poly (methyl methacrylate) (PMMA) and polystyrene (PS), were mechanically blended with MWNT/PANI nanoparticles and percolated at respective weight percentages of 0.25,0.85 and 1.25. FESEM and Hall Effect Measurement System analyses show strong doping effect between nanoparticles and matrices, which provides excellent dispersion of MWNT/PANI nanoparticle in the matrix. Better charge transition is obtained for MWNT/PANI/polymer composites by replacing the insulating polymer with the conductive and less-resistant PANI polymer. The same change is also responsible for the hybrid nanoparticle’s low electrical percolation.