Highly conductive and stretchable poly(dimethylsiloxane):poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) blends for organic interconnects

Naturally immiscible PEDOT:PSS and PDMS, which are a typical conducting polymer and an transparent elastomer, respectively, were blended by the support of PDMS-b-PEO. A block copolymer, PDMS-b-PEO, consisting of hydrophobic PDMS backbones and hydrophilic PEO side chains, significantly improved the miscibility of PEDOT:PSS and PDMS. At an optimal PDMS-b-PEO concentration of 30%, a cured PEDOT:PSS:PDMS film was found to be comprised of three-dimensional PDMS networks and a PEDOT:PSS phase filling in between the networks. The optimal blend film exhibited a conductivity comparable to a pure PEDOT:PSS film and a maximum strain to rupture of about 75%. It was also demonstrated that interconnects made of this blend film functioned well irrespective of the substrate and the pattern size, and could reproducibly operate under strains up to 50%. These results indicate that the PEDOT:PSS:PDMS blends could be a practical choice for organic interconnects for future stretchable electronics.