Mixtures of Colloidal Electrolytes with Uni-univalent Salts.

Abstract

Owing to the dearth of information as to the effect of mixtures of colloidal electrolytes and uni-univalent salts upon each other, the following data are instructive. One of the more interesting results of the study of colloidal electrolytes (1,4,5,7,9) is that the ionic strength principle does 493

Aggregation of sodium dodecylsulfate in aqueous nitric acid medium

“…The values of j of SDS in water (in the absence of HNO 3 ) and in aqueous HNO 3 solutions calculated from Eqs. (1), (2), (11), and (14) are shown in Fig. 1 (red lines) and they are in good agreement with the experimental values.…”

“…The unusual behavior in j can be explained in light of Eqs. (11)and(14). Below the cmc, j increases with increasing SDS concentration in accordance with Eq (11)…”

“…For example, if I calculated by including the contribution from ionic micelle is substituted in the DHO equation then molar conductance becomes even negative at surfactant concentrations sufficiently higher than cmc. Based on conductivity and freezing point depression data, McBain and Searles [14] first reported that the ionic strength principle does not apply to ionic micelles and showed that I of ionic micelles resemble that for a uni-univalent electrolyte. Pashley and Ninham [15] as well as Richetti and Kekicheff [16] measured double-layer forces between two molecularly smooth mica surfaces coated with adsorbed bilayers of cetyltrimethylammonium bromide (CTAB) and separated by an aqueous solution of CTAB.…”

“…Different values for shielding factor were also tested in the earlier studies [5,6] while analyzing the conductivity data of ionic surfactant solutions. In light of the above reports [5,6,[14][15][16][17][18][19][20][21] we calculated I in the present study by using the expressions…”

Aqueous Solutions of Paraffin-Chain Salts.

“…McBain has argued that, since the ionic charges on the micelle surface are separated from each other by several atomic diameters, their electrostatic effects will be essentially independent. As experimental evidence supporting this assumption, Mc-Bain and Searles (25) and McBain and Brady (24) have measured freezing points and conductivities of solutions containing both paraffin-chain salts and simple salts and have found that the effects are essentially additive. Some doubt may be cast on the interpretation of these data by the fact that the number, size, and electrical charge of the micelles may be changed by the presence of the added salt, which may lead to a set of compensating factors.…”