导电聚合物纳米线的制备及气敏性能研究

Preparation and gas sensitivity of conducting polymeric nanowires

首次采用简单的浸润多孔氧化铝（AAO）模板法制备了导电聚合物聚-3，4-乙烯二氧噻吩（PE—DOT）纳米线。导电聚合物溶液浸润AAO模板后，PEDOT吸附于孔道壁并进一步聚合生成导电聚合物纳米线。紫外-可见光-近红外光谱（UV—vis—NIR spectrum）分析表明生成的纳米线处于掺杂态。采用四探针仪分析了导电聚合物纳米线的导电性能，结果显示纳米线电导率相比普通PEDOT材料有数量级增加，且表现出良好的掺杂／脱掺杂能力。研究了导电聚合物纳米线的气体敏感性能，发现其对挥发性醇类，尤其对甲醇在较低浓度下表现出优异的敏感性，对5×10^-6甲醇气体的响应时间约为10～20s，测试可重复性超过20次，达到饱和吸附时的气体浓度明显大于普通PEDOT材料。表明PEDOT纳米线不仅提供了较大表面积供气体分子吸附，而且纳米线中导电通道取向一致，从而体现出较好的气体敏感性能。

Conducting polymer nanowires of poly（3,4-ethylene dioxythiophene） （PEDOT） was firstly prepared by an simple wetting anodic aluminium oxide template （AAO） method. The AAO template was wetted by PEDOT polymer solution and the conducting polymer nanowires was formed into the hole of template. The formed PEDOT nanowires was characterized by UV-vis-near IR （UV-vis-NIR） absorption spectrum, and the result showed that the nanowires was in a doped state. The size of obtained nanowires was larger than the size of AAO template pore, which resulted from a swelling effect of polymer after removing AAO template. Conductivity investigation showed that nanowires had higher conductivity than conventional bulk PEDOT materials and exhibited excellent doping/dedoping characteristic. For the sensitive characteristics study, the PEDOT nanowires showed faster response to different analyte gas, such as methanol and ethanol, and especially showed excellent gas sensitivity to methanol gas. It has been found that at 5ppm methanol concentration, the nanowires exhibits short response time about 10-20s and the reproducible gas sensitivity can be achieved more than 20 times at same testing condition. This excellent gas sensitivity of PEDOT nanowires was ascribe to the higher surface area ratio of nanowires and ordered PEDOT conductive channel in nanowires, which supply well condition for analyte gas to diffuse into and out from the nanowires.