Optically anisotropic polyethylene-gold nanocomposites

Gold colloids coated with a self-assembled monolayer of an alkanethiol were introduced into a polyethylene matrix by means of solution-casting techniq ues. We oriented the resulting nanocomposites by uniaxial drawing in the so lid state. The absorption spectra of the drawn nanocomposites in the visibl e wavelength region were found to depend strongly on the polarization direc tion of incident light. The materials appeared, for instance, red or blue i f the Light was polarized perpendicular or parallel, respectively, to the d rawing axis. The observed optical anisotropy is thought to originate in the morphology of the composites that composed uniaxially oriented, pearl-neck lace arrays of nanoparticles with a high aspect ratio, as observed in trans mission electron microscopy. It is shown that the polymer-inorganic nanocom posites can be employed as color polarizing filters. (C) 1999 Optical Socie ty America.