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It is shown that the reported differences in anionic surfactant adsorption on cotton can be largely attributed to the presence of variable amounts of natural wax on the fiber surface. High adsorption values with peaks near critical micelle concentration (cmc) result from surfactant adsorption on the wax surface. Wax-free surfaces fail either to show the same high maxinm or the same relative magnitude of adsorption. At surfactant emc the adsorption relationship for waxy cotton (millimoles/g. of cotton) cationic : nonionic : anionic was roughly 66 to 17 to 74. For dewaxed cotton, this beealne 40 to 10 to nil.Confirming the findings of others, no adsorption by cotton of sodium tripolyphosphate oecurs either with waxy or wax-free cotton. Also addition of tripolyphosphate decreased the a,1sorption of several anionic surfactants.At concentrations greater than emc and ~t sufficiently-high solution temperature, anionic surfactants can solubilize eotton wax, leaving a less waxy substrate upon which adsorption is then reduced. C ONSIDERABLE VARIATION ill_ the adsorption of surfactants upon cotton has been noted in published data and ascribed to surfaetant purity and adsorption technic (12). Sorption maxima and kink points in the adsorption isotherm were detected in the region of critical micelle concentration (cme) by Evans (7), Meader and Fries (19), Fava and Eyring (9), and Sexsmith and White (22). Weatherburn and Bailey (27) found that sorption increased logarithmically to a constant value in the cmc range. In contrast, Jayson (14) and Boyd and Bernsteiu (3) failed to show the maxima at near cmc. The data of Perry and coworkers (21) point up the differences in magnitude of adsorption, which it is apparent are not explained simply by either surfactant purity (or sample) or adsorption technic.Even though adsorption technics may vary. the marked differences in values were apparently to be found in another variable, the substrate. It is known that raw cotton varies widely in character, and it is likely that physical and chemical treatment of the fiber and fabric changes fiber characteristics still further.In attempting clarification of the mechanism of action of sodium carboxymethyl cellulose (NaCMC). Nieuwenhnis and Tan (20) found that solvent-extracted unbleached cotton and bleached fiber varied considerably. The latter exhibited the protective action of NaCMC. Epton and Preston (6) demonstrated that the nitrogen content of raw cotton caused a variation in surfactant adsorption; this increased with increasing nitrogen content. Others, recognizing that the condition of cotton could affect their results materially, resorted to various types of preparatory procedure. Sookne and Harris (24) prepared standard cellulose by ethanol extraction, followed by a boil with 1~. sodimn hydroxide solution, providing dewaxed and depectinized fiber. Wahba (26) prepared "standard" cellulose by high pressure boiling of cotton linters in caustic soda solution, the fiber to be used for estimation of moisture adsorption.] 38This brief review d...

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Electrokinetic forces are of considerable importance in the mechanism of soil removal and redeposition. One electrokinetic measurement is that of the difference in potential between the immovable layer attached to the surface of a solid phase (soil or substrate) and the movable part of the diffuse layer in the body of the detergent liquid, and is termed zeta potential. Correlations have been obtained which indicate that, in a de tergent system, it is desirable that the zeta potentials of soil particles and substrate become nearly equal to reduce attractive forces tending to cause them to adhere. The effect of surfactants and electrolytes upon the zeta potential of soils and sub strates has been collated, permitting an estimate of the areas in need of further elucida tion. Cited are available correlations between zeta potential and suspension values, critical micelle concentration, and detergency values.