Gold Composite- and Macroporous Gold Nanoparticle Films by a Vertical Deposition Method

摘要

Composite films have been prepared in one step by a vertical deposition method from the aqueous suspension of gold colloids and polystyrene (PS) microspheres. The composite is formed on a glass substrate by convective assembly from the evaporating meniscus of the suspension. Au-PS composite films appear opalescent and SEM observations have shown that the structure of the composite is partially ordered. The film is "stripe" structured and made of close-packed PS microspheres separated by narrow (around 500 nm) gold filaments. The formation of filaments is accounted for by the strong attractive van der Waals forces between Au particles. The formation of Au filaments is also confirmed by the presence of a plasmon resonance band at 690-736 nm. The non-uniform self-assembly is accounted for by the disrupting effect of the gold nanoparticles. The structure of the composite prepared by the vertical deposition is compared to that of the ready made template infiltrated by gold by a chemical or electrochemical method. A macroporous gold film formed by evenly spaced 500 nm wide filament is obtained from the composite after the removal of PS by dissolution. The fabrication of both composites and macroporous gold films may find a range of applications, such as catalytic and SERS supports and optical coatings.