Direksilp Chatrawee, Sirivat Anuvat
The Conductive and Electroactive Polymer Research Unit, The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330, Thailand.
Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University Research Building, Soi Chula 12, Phayathai Road, Bangkok 10330, Thailand.
Polymers (Basel). 2020 May 1;12(5):1023. doi: 10.3390/polym12051023.
Poly(N-methylaniline) (PNMA) is a polyaniline derivative with a methyl substituent on the nitrogen atom. PNMA is of interest owing to its higher solubility in organic solvents when compared to the unsubstituted polyaniline. However, the electrical conductivity of polyaniline derivatives suffers from chemical substitution. PNMA was synthesized via emulsion polymerization using three different anionic surfactants, namely sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and dioctyl sodium sulfosuccinate (AOT). The effects of surfactant structures and concentrations on electrical conductivity, doping level, crystallinity, morphology, and thermal stability were investigated. The re-doping step using perchloric acid (HClO) as a dopant was sequentially proceeded to enhance electrical conductivity. PNMA synthesized in SDBS at five times its critical micelle concentration (CMC) demonstrated the highest electrical conductivity, doping level, and thermal stability among all surfactants at identical concentrations. Scanning electron microscopy (SEM) images revealed that the PNMA particle shapes and sizes critically depended on the surfactant types and concentrations, and the doping mole ratios in the re-doping step. The highest electrical conductivity of 109.84 ± 20.44 S cm and a doping level of 52.45% were attained at the doping mole ratio of 50:1.
聚（N-甲基苯胺）（PNMA）是一种在氮原子上带有甲基取代基的聚苯胺衍生物。与未取代的聚苯胺相比，PNMA因其在有机溶剂中具有更高的溶解度而备受关注。然而，聚苯胺衍生物的电导率会受到化学取代的影响。PNMA是通过乳液聚合使用三种不同的阴离子表面活性剂合成的，即十二烷基硫酸钠（SDS）、十二烷基苯磺酸钠（SDBS）和二辛基磺基琥珀酸钠（AOT）。研究了表面活性剂结构和浓度对电导率、掺杂水平、结晶度、形态和热稳定性的影响。依次进行使用高氯酸（HClO）作为掺杂剂的再掺杂步骤以提高电导率。在SDBS中以其临界胶束浓度（CMC）的五倍合成的PNMA在相同浓度的所有表面活性剂中表现出最高的电导率、掺杂水平和热稳定性。扫描电子显微镜（SEM）图像显示，PNMA颗粒的形状和尺寸严重依赖于表面活性剂的类型和浓度以及再掺杂步骤中的掺杂摩尔比。在掺杂摩尔比为50:1时，获得了最高电导率109.84±20.44 S/cm和掺杂水平52.45%。
