SERRS spectra of azo dyes from deposited Ag colloid-azo dye films: investigating the mechanism of film formation

The role of interphase transfer of azodye adsorbates in the mechanism of in terfacial Ag colloid-azodye films formation was investigated. Ag colloid - azodye [azodye = methyl yellow (MY) or methyl red (MR)] were prepared by vi gorous shaking of a two phase system consisting of an acidified Ag hydrosol of pH = 3 [Ag colloid (ac)] and a solution of the azodye in dichloromethan e. SERRS spectra of the glass deposited films were measured and compared to RR spectra of the ate-form in the dichloromethane solution and to RR spect ra of the hydrate-form present in an acidified aqueous solution of the dye. The presence of the characteristic bands of the hydrate-form of the dyes b oth in Ag colloid (ac)-MY and Ag colloid (ac)-MR films provides evidence fo r the contact of the azodyes with the acidified aqueous phase in the course of the film formation. (C) 1999 Elsevier Science B.V. All rights reserved.