Aqueous gold sols of rod-shaped particles prepared by the template method

Aqueous gold sols of rod-shaped particles are obtained by electrochemical deposition of gold into porous aluminum oxide membranes followed by dissolution of aluminum oxide and stabilization of the rods with different polymers. The visible absorption spectra of the sols show one absorption maximum, λmax, at around 530 nm. With increasing aspect ratio, the maximum shifts to short wavelength, which is in agreement with theoretical predictions. Absorption spectra of the sols show that the presence of polyvinyl alcohol or poly(vinylpyrrolydon) as stabilizer can improve the dispersity of aqueous gold sols, and then stable sols of the rods are obtained.