Effect of Modified Nano Silica on the Conductivity and Morphology Characteristics of Oxalic Acid-Doped Polyaniline Composites

Oxalic acid-doped polyaniline (OA-PANI) was incorporated with nano silica and amino silane-modified nano silica. The polymerization of aniline to produce OA-PANI incorporating nano silica (OA-PANI-NS) and PANI incorporating 3-amino-propyltriethoxysilane modified nano silica (OA-PANI-NS-AS) were carried out in 0.1 M oxalic acid in the presence of ammonium persulphate as an oxidizing agent. Different amounts of nano silica and 3-amino-propyltriethoxysilane modified nano silica (13%, 15%, 20%, 30% and 50% w/w) were incorporated with OA-PANI to investigate its conductivity behavior using an impedance test. The successful formations of OA-PANI-NS and OA-PANI-NS-AS were confirmed by FTIR. The morphology of OA-PANI-NS and OA-PANI-NS-AS were studied using XRD and FESEM. Based on the results, the conductivity of OA-PANI-NS and OA-PANI-NS-AS increased linearly with the increased amount of nano silica and 3-amino-propyltriethoxysilane-modified nano silica w/w%, from 13 to 20% w/w. Further increased in the amount of both fillers caused a significant decreased in the conductivity of OA-PANI-NS and OA-PANI-NS-AS. The maximum electrical conductivity achieved for OA-PANI-NS and OA-PANI-NS-AS were 1.43 x 10(-4) Scm(-1) and 4.0 x10(-6)S cm(-1), respectively. Lower conductivity of OA-PANI-NS-AS compared to OA-PANI-NS due to the presence of 3-amino-propyltriethoxysilane inhibited the ion movement in the OA-PANI matrix caused by the agglomeration phenomenon.

Automated summary

Incorporating different amounts of nano silica and 3-amino-propyltriethoxysilane modified nano silica into OA-PANI led to an increase in conductivity up to a certain percentage, but excessive fillers caused a significant decrease in conductivity. The maximum electrical conductivity achieved for OA-PANI-NS and OA-PANI-NS-AS were 1.43 x 10(-4) Scm(-1) and 4.0 x10(-6)S cm(-1), respectively. The lower conductivity of OA-PANI-NS-AS compared to OA-PANI-NS was attributed to the inhibition of ion movement by the presence of 3-amino-propyltriethoxysilane.