Effect of Sodium Barbital on the Physico-chemical Properties of Surfactants with Different Charges

Abstract

The effects of sodium barbital (SB) on the solubility of different kinds of surfactants viz., CTAB (cationic head group), SDS (anionic head group) and Triton X-100 (non ionic head group) in solution phase as well as their first and second critical micelle concentrations (CMC1 and CMC2), the change in Kraft temperatures (TK) and cloud points (CP) have been studied. Furthermore, the article reports SB-surfactant interaction study, which is application oriented and highlights the underlying physico-chemical aspects of the system through florescence and conductivity measurements. The results show that the solubility of CTAB and Triton X-100 increases with the addition of SB, and that of SDS increases in the presence of small amounts of SB and decreases in the presence of large amounts of SB. With the increasing SB concentration, the CMC of CTAB and CMC1 of Triton X-100 both increase, while the CMC of SDS decreases, and the CMC2 of Triton X-100 has no obvious change. The addition of SB decreases the TK of CTAB sharply, but it increases the TK of SDS and the CP of Triton X-100. The different effects of SB on the physico-chemical properties of differently charged surfactants may be related to its different interactions with the surfactants.