Abstract

An in-situ chemical polymerization method maintaining a low temperature in the range of 0–5 °C was used to synthesize nanocomposites with different weight percentages of cobalt aluminum oxide (CAO) in polypyrrole (PPy). Structural, morphological, elemental, and particle size characterizations were done by employing X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM), respectively. The XRD analysis revealed the amorphous nature of pure PPy and the crystalline peaks of CAO along with the diminishing amorphous peak of PPy for the PPy/CAO nanocomposites. The SEM and TEM studies of PPy and PPy/CAO nanocomposites in powder form showed aggregates of the spherical particles with individual particle sizes of around 500 nm for pure PPy and in the range of 120–210 nm for the nanocomposites. The energy band gaps for pure PPy and the nanocomposites were analyzed by UV–VIS spectroscopy and were such that they can be considered for wide bandgap applications. Characterization of the temperature variation of the dc conductivity was carried out for all nanocomposites and found to be of the semiconductor type conduction. The humidity sensing properties of the pure PPy and its nanocomposites were studied and an improvement in the sensing properties of PPy by the addition of CAO was found.

摘要

一种原位化学聚合法可将温度维持在0-5°C的低温范围，用于合成纳米复合材料，其中聚吡咯（PPy）中钴氧化铝（CAO）的重量百分比不同。通过分别使用X射线衍射（XRD），扫描电子显微镜（SEM），能量色散X射线分析（EDX）和透射电子显微镜（TEM）进行结构，形态，元素和粒度表征。XRD分析表明，对于PPy / CAO纳米复合材料，纯PPy具有无定形性质，CAO具有结晶峰，而PPy具有无定形峰。粉末形式的PPy和PPy / CAO纳米复合材料的SEM和TEM研究表明，球形颗粒的聚集体，对于纯PPy而言，单个粒径约为500 nm，对于纳米复合材料，其粒径在120-210 nm范围内。通过UV-VIS光谱分析了纯PPy和纳米复合材料的能带隙，因此可以考虑将它们用于宽带隙应用。对所有纳米复合材料都进行了直流电导率温度变化的表征，发现其具有半导体类型的导电性。研究了纯PPy及其纳米复合材料的湿度传感特性，并发现通过添加CAO可以改善PPy的传感特性。通过UV-VIS光谱分析了纯PPy和纳米复合材料的能带隙，因此可以考虑将它们用于宽带隙应用。对所有纳米复合材料都进行了直流电导率温度变化的表征，发现其具有半导体类型的导电性。研究了纯PPy及其纳米复合材料的湿度传感特性，并发现通过添加CAO可以改善PPy的传感特性。通过UV-VIS光谱分析了纯PPy和纳米复合材料的能带隙，因此可以考虑将它们用于宽带隙应用。对所有纳米复合材料都进行了直流电导率温度变化的表征，发现其具有半导体类型的导电性。研究了纯PPy及其纳米复合材料的湿度传感特性，并发现通过添加CAO可以改善PPy的传感特性。