Preparation, structure and properties of uniaxially oriented polyethylene-silver nanocomposites

Uniaxially oriented composites of high-density polyethylene and silver nano particles were prepared using solution-casting, melt-extrusion and solid-st ate drawing techniques. The absorption spectrum in the visible wavelength r ange of the drawn nanocomposites was observed to strongly depend on the pol arisation direction of the incident light. For instance, the nanocomposites appear bright yellow or red when the vibration direction of linearly polar ised light is perpendicular or parallel, respectively, to the drawing axis. The optical anisotropy of the drawn nanocomposites originates from uniaxia lly oriented, pearl-necklace type of arrays of nanoparticles of high aspect ratios. The absorption spectrum of the nanocomposites can be shifted to hi gher wavelengths using appropriate annealing procedures. The annealing resu lts in an increased size of the primary silver particles, due to Ostwald ri pening, and consequently a range of polarisation-dependent colours can be g enerated in the drawn nanocomposites. (C) 1999 Kluwer Academic Publishers.