Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/nylon 6 nanofiber web treated with repetitive coating cycles and dimethyl sulfoxide multi-step treatment for electronic textiles

Highly conductive nylon 6 nanofiber web was fabricated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and dimethyl sulfoxide (DMSO) for electronic textiles. To improve electrical conductivity, repeated coating with PEDOT:PSS and multi-step treatment of DMSO was performed. The effects of these treatments on electrical conductivity, surface properties, and chemical structures were investigated. For repetitive coating cycles, pristine PEDOT:PSS dispersion was dropped onto a nylon 6 nanofiber web for between one and four times of coating. For DMSO multi-step treatment, in the one-step treatment, the nanofiber web was repeatedly treated using PEDOT:PSS doped with DMSO. In the two-step treatment, the nanofiber web was repeatedly treated with doped PEDOT:PSS at first and, then, it was immersed in a DMSO bath. As a result, the sheet resistance decreased dramatically as the number of coating cycles increased. When the two-step treatment was applied, the sheet resistance was much lower compared to that of the one-step treatment, and thereby sample PD4-D with the lowest resistance showed 6.56 Ω/sq. As a result, the surface of the nanofiber web was covered with more PEDOT:PSS as the coating cycle was repeated. The PEDOT particles became large and long shapes after the two-step treatment of DMSO. This inferred that the contact area among conducting PEDOT particles increased because insulating PSS was removed by DMSO. In addition, the presence of PEDOT:PSS and nylon 6 was confirmed. This study proved that the simultaneous treatments of repeated coating with PEDOT:PSS and multi-step treatment of DMSO can improve electrical conductivity, and it developed the highly conductive PEDOT:PSS/nylon 6 nanofiber web.