Amylose-directed synthesis of CuS composite nanowires and microspheres.

Reported are the synthesis and characterization of CuS composite nanowires and microspheres in the presence of amylose. The preparation involved first the complexation of amylose with Cu(2+) of CuCl(2) at 70°C. Cu(2+) complexation was confirmed by a conductivity reduction of CuCl(2) after amylose addition. Also, the aggregation state of the amylose changed after Cu(2+) as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). At the Cu(2+) to α-D-glucopyranosyl unit molar ratio r of 0.70 and 1.41, the amylose aggregated into microspheres that were approximately 150 and 250 nm in diameter. Adding sodium thiosulfate resulted in the production of an amorphous precipitate consisting presumably of CuS(2)O(3). At r=0.70 and 1.41, CuS(2)O(3) precipitated inside the template of Cu(2+)/amylose microspheres as nanoparticles, while a twisted nanowire-like structure was produced at r=0.92. CuS(2)O(3) decomposed under heating at 100 °C to yield crystalline CuS nanoparticles.