磺化聚苯乙炔/多壁碳纳米管复合材料导电特性和机理的研究

将磺化聚苯乙炔(SPPA)与多壁碳纳米管(MWCNTs)超声共混制备得到SPPA/MWCNTs复合材料. 用X光电子能谱仪、固体紫外-可见分光光度计、X射线衍射仪、四探针、场发射扫描电镜等对复合材料导电特性及机理进行研究. 结果表明: SPPA/MWCNTs 复合材料中SPPA与MWCNTs发生电荷转移而被掺杂, 并且由于SPPA与MWCNTs间的电荷转移, 彼此间存在一定的相互作用力; 复合材料电阻呈负温度系数效应; SPPA/MWCNTs复合材料电导率发生两次突跃. 可能的导电机理为, 复合材料中SPPA不仅被MWCNTs物理填充, 同时还被MWCNTs掺杂, 复合材料中存在两种导电通路, 一是SPPA与MWCNTs的碳原子发生电荷转移而被掺杂, 彼此之间存在一定的相互作用力, 导致SPPA包裹MWCNTs形成独立导体单元, 这种独立单元相互接触形成导电通路; 二是MWCNTs彼此之间相互接触形成导电通路, 并建立了该导电机理的理论模型.

Studies on Conductive Properties and Mechanism of Composites-Sulfonated Polyphenylacetylene/Multiwalled Carbon Nanotubes

Sulfonated polyphenylacetylene/multiwalled carbon nanotubes (SPPA/MWCNTs) composites were prepared by blending SPPA with MWCNTs in ultrasonic bath. Conductive properties and conductive mechanism for the SPPA/MWCNTs were investigated using X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectrometer (UV), X-ray diffraction (XRD), four-point probe and field emission scanning electron microscopy (FESEM) techniques. The results indicate that charge transfer occurred between SPPA and MWCNTs, SPPA were doped by MWCNTs, and some interaction existed between MWCNTs and SPPA, originating from charge transfer. The dependencies of conductivity on temperature showed negative temperature coefficient (NTC) of resistance. The composite conductivities had two obvious increases. The conductive mechanism is supposed as follows. SPPA were both filled and doped by MWCNTs, and two types of conductive systems existed in the SPPA/MWCNTs composites. One was formed by connecting of conductive units (conductive units were formed via SPPA wrapping MWCNTs); and the other formed by contacting of MWCNTs. Furthermore, a theoretical model was built to explain the conductive mechanism.