Scalable Electrically Conductive Spray Coating Based on Block Copolymer Nanocomposites

Abstract

Currently available conductive inks present a challenge to achieving electrical performance without compromising mechanical properties, scalability, and processability. Here, we have developed blends of carbon black and the commercially available triblock copolymer (BCP), poly(styrene-ethylene-butylene-styrene)-g-maleic anhydride (SEBS-g-MAH) (FG1924G, Kraton), that can be readily applied as a conductive coating via a spray-coating process, for a wide range of insulating materials (fabric, wood, glass, and plastic). Simple but effective mechanical and chemical modifications of the ingredients can increase the electrical conductivity (∼100 S/m) by an order of magnitude more than previously reported for carbon black composites; moreover, the coatings display excellent mechanical flexibility (tensile strain ε ∼ 5.00 mm/mm). To correlate electrical conductivity and nanoscale structural changes with mechanical deformation, small-angle X-ray scattering (SAXS) during in situ tensile testing was performed. We show that the nanocomposite can be produced using low-cost ingredients (∼$ 10/kg), ensuring scalability for fabrication of large-scale devices without specialized material synthesis. Equally important, the phase behavior of block copolymers can enable recovery from physical damage via thermal annealing, which is critical for product longevity.