The leaching of Rhodamine B, Naphthol Blue Black, Metanil Yellow and Bismarck Brown R from silica deposits on polyester and viscose textiles

Rhodamine B (RB), Naphthol Blue Black (NBB), Metanil Yellow (MTY) and Bismarck Brown R (BHR) immobilized within a modified silica sol were used for the surface dyeing of textiles, namely polyester and viscose fabrics. Silica sols were characterized by FTIR and dynamic light-scattering measurements. The sol was dip-coated onto the fabrics and deposits were formed. Three similar procedures for the formation of silica deposits, using tetraethoxysilane (TEOS) and (3-glycidoxypropyl)trimethoxysilane (GPTMS) as precursors in acidified ethanol, were tested. Interactions between dyes and silica precursors were investigated by FTIR measurements. Leaching was detected and quantified by UV–Vis measurements on the composition of washing solutions. Incorporation of GPTMS into silica sols reduces dye leaching from the silica deposits.