Enhanced electrical conductivity of polymer microspheres by altering assembly sequence of two different shaped conductive fillers

Abstract

Conductive microspheres are prepared using two different shaped conductive fillers, carbon nanotubes (CNTs) and Au nanoparticles (AuNPs), by a dry particle coating (DPC) process and a self-assembly method. CNTs, which are one-dimensional conductive fillers, facilitate the formation of conducting pathways so that the zero dimensional AuNP content can be significantly reduced to obtain electrical percolation from the conductive microspheres. Two fabrication methods are investigated: (1) the self-assembly of AuNPs followed by the DPC of the CNTs on polystyrene (PS) microspheres (t-PS/AuNP/CNT) and (2) the DPC of the CNTs followed by the self assembly of AuNPs (PS/t-CNT/AuNP). In both cases, the electrical percolation of the conductive microspheres is achieved using a significantly lower amount of AuNPs (1 wt%), which is 17 times lower than that of samples prepared using only AuNPs (17 wt%). Interestingly, each sample exhibits distinct conducting behaviors with different amounts of AuNPs owing to the different hybridization structures of AuNPs and CNTs.