Dipolar interaction, desorption

These are defined as anionic dyes with substantivity for cellulosic fibres applied from an aqueous dyebath containing an electrolyte. The forces that operate between a direct dye and cellulose include hydrogen bonding, dipolar forces and non-specific hydrophobic interaction, depending on the chemical structure and polarity of the dye. Apparently multiple attachments are important, since linearity and coplanarity of molecular structure seem to be desirable features (section 3.2.1). The sorption process is reversible and numerous attempts have been made to minimise desorption by suitable aftertreatments (section 10.9.5). The two most significant non-textile outlets for direct dyes are the batchwise dyeing of leather and the continuous coloration of paper. 

The interactions between the dipoles and ions in biopolymen are important in many respects. The physiological significance trf piezoelectric and pyroelectric effects, if any. could be the influence of the electrical polarization of biopolymets on the behavior of ions. One possible example would be the interaction of the ion chaimel proteins with kms. The applied stress, mechanical or electrical, may change the molecular conformation, which is associated with the dipolar roiatioo. The adsorption and desorption of ions to the protein molecule could be affected by the conformational change of molecule. An enzymatic reaction accompanied by a change of mdecular conformatioo could be another example. 

---