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Aggregation Behaviour of Acid Dyes in N,N ‐Dimethylformamide‐Trichloroethylene Solvent Mixtures ‐ A Quasielastic Light‐scattering Study
Author(s) -
Chavan R B,
Rao J Venkata
Publication year - 1983
Publication title -
journal of the society of dyers and colourists
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 0037-9859
DOI - 10.1111/j.1478-4408.1983.tb03678.x
Subject(s) - chemistry , trichloroethylene , solvent , dimethylformamide , aqueous solution , acid dye , light scattering , molecule , photochemistry , organic chemistry , inorganic chemistry , scattering , dyeing , physics , optics
A new technique, quasielastic light scattering, was employed to study the aggregation behaviour of three acid dyes in dimethylformamide—trichloroethylene solvent mixtures. Observations on the aggregation of these dyes showed that they behaved differently in these mixtures than in aqueous solution. The extent of aggregation was found to vary with the number of sulphonic acid groups present in the dye molecule. Both monosulphonated and disulphonated acid dyes showed a tendency to aggregate with increase either in dye concentration or in trichloroethylene content in dimethylformamide. The low dielectric constant of trichloroethylene was responsible for the tendency of dye to aggregate with increase in trichloroethylene content. The trisulphonated acid dye showed least tendency to aggregate; this may be accounted for by the fact that sulphonic acid groups in the dye molecule are located at sites unfavourable to aggregation.