| Abstrakt: |
A family of two-headed surfactants, the disodium 4-alkyl-3-sulfonatosuccinates, has been synthesized by the monoesterification of maleic anhydride and the addition of sodium bisulfite to the corresponding monoester. The properties the micelles formed by these compounds in aqueous solution, and the conformations of the chains comprising the micellar interior, have been investigated using a combination of 1-D nmr experiments and homonuclear and heteronuclear 2-D nmr techniques. The critical micelle concentrations (cmc's) and the aggregation numbers determined from the nmr experiments indicate that, in agreement with the earlier literature on other two-headed surfactant systems, these amphiphiles have high cmc's and low aggregation numbers when compared to single-headed surfactants of comparable chain length. All these results are interpreted in terms of the effect of adding a second headgroup to a single-headed, single-tailed surfactant.Key words: micelles, surfactants, nmr spectroscopy, chemical shifts, aggregation numbers. |
