Affinity of disperse dyes on poly(ethylene terephthalate) in non-aqueous media. Part 2: effect of substituents

Adsorption properties of the 10 kinds of disperse dyes having different substituents were examined using several representative non-aqueous media on to poly(ethylene terephthalate) substrates. The dye adsorption amounts in pentane medium representing alkanes were much higher than those in the other non-aqueous media. In pentane medium, as the hydrophobicity of the dyes resulting from the substituents of dye molecules increased, the solubility of the dyes increased and the corresponding dye adsorption greatly decreased. This finding was coincident with the results from the previous study that the adsorption amount of disperse dyes on to substrates was inversely proportional to the solubility of the dyes. Furthermore, the hydrophobicity and the hydrophilicity of the dyes were discussed in terms of the electric dipole moments which are obtained by a semiempirical method using molecular modeling software.