Adsorption phenomena involving noionic surfactants can be explained on the basis of hydrophoblic interaction, in some cases coupled with steric effects. Electrolytes have no direct influence on adsorption with noionic surfactants. Nonionic surfactant detergency performance is adversely affected by the presence of polyvalent cations. These cations cause reduced negative potentials of fiber surface and soil, leading to repulsion and correspondingly poor soil removal.an important advantage of nonionic surfactants of the alcohol ethoxylate type is the fact that a proper balance can be easily achieved between the hydrophobic and hydrophilic portion of the nonionic surfactants. For example, the hydrophilic portion of the molecule can be extended gradually by stepwise addition of ethylene oxide moieties. This leads to a stepwise increase in hydration and corresponding successive increase in solubility. On the other hand, with ionic surfactants, the presence of even one ionic group makes such a strong contribution to hydrophilic character that the introduction of further ionic groups totally eliminates the possibility of any equilibrium relationship with respect to the hydrophobic portion. The result is a rapaid deterioration of typical surfactant characteristics. For a surfactant bearing two strong ionic hydro-philic groups to show washing activity, a considerably longer alkyl chain would be necessary.
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