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 Cu2+ of CuCl2 at 70 °C. Cu2+ complexation was confirmed by a conductivity reduction of CuCl2 after amylose addition. Also, the aggregation state of the amylose changed after Cu2+ as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). At the Cu2+ 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 CuS2O3. At r = 0.70 and 1.41, CuS2O3 precipitated inside the template of Cu2+/amylose microspheres as nanoparticles, while a twisted nanowire-like structure was produced at r = 0.92. CuS2O3 decomposed under heating at 100 °C to yield crystalline CuS nanoparticles.