Electrically conductive polymeric photonic crystals

Electrically conductive polymeric 3D photonic crystals are prepared by the shear ordering of composites consisting of monodisperse core-shell polymer spheres and single-walled carbon nanotubes (SWNTs). Strong iridescent colour indicates that the highly ordered opaline structures are not disrupted by the presence of the conductive nanotube networks. Thermal annealing leads to a significant increase in the overall electrical conductivity of thin-film samples yielding DC conductivities of 10(-4) S cm(-1), with percolation thresholds of less than 0.4 wt% of SWNT. Such composites with open networks of carbon nanotubes held apart by lattices of hard spheres, give combined conductive properties and structural colour effects, within a tuneable viscoelastic medium, with many potential functional applications.