NMR Studies of Aggregation and Hydration of Surfactants Containing Amide Bonds

@article{citeulike:2970639, abstract = {Abstract: The consequences of including amide bonds into the structure of short-chain nonionic surfactants have been studied. Of particular interest were the possible effects of the hydrogen bonding ability of the amide group on the micellar shape. The aggregate structure and hydration of two different amide-containing surfactants, C7H15CO-NH-(CH2CH2O)4H and C7H15CO-(NH-C3H6-CO)2N(CH3)2, were investigated using NMR diffusometry (pulsed gradient spin echo NMR) as the main technique. Data from experiments on the surfactants, the hydrophobic probe molecule hexamethyldisilane (HMDS), and water were interpreted to gain information about the solution structures, and the results were compared to those on a previously studied alcohol ethoxylate surfactant of similar size, C8E4. Both of the amide-containing surfactants form small micelles within the whole investigated concentration range. At the critical micelle concentration, the aggregates are most probably spherical, and with increasing surfactant concentration there are indications of either a minor aggregate growth or agglomeration of the micelles. In addition, it was found that the presence of amide groups in the surfactant inhibits the intermicellar transport of HMDS, which occurs in the C8E4 system. From measurements on water diffusion in the three surfactant systems, it could be concluded that the surfactant hydration is higher when amide bonds are present.}, address = {Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, 412 96 G\"{o}teborg, Sweden, and Department of Chemistry, Emory University, Atlanta, Georgia 30322}, author = {Stjerndahl, M. and Lundberg, D. and Zhang, H. and Menger, F. M. }, citeulike-article-id = {2970639}, doi = {http://dx.doi.org/10.1021/jp0658492}, journal = {J. Phys. Chem. B}, keywords = {detergents, diffusion, nmr}, month = {March}, number = {8}, pages = {2008--2014}, posted-at = {2008-07-07 18:28:23}, priority = {5}, title = {NMR Studies of Aggregation and Hydration of Surfactants Containing Amide Bonds}, url = {http://dx.doi.org/10.1021/jp0658492}, volume = {111}, year = {2007} }

TY - JOUR ID - citeulike:2970639 L3 - citeulike-article-id:2970639 TI - NMR Studies of Aggregation and Hydration of Surfactants Containing Amide Bonds JF - J. Phys. Chem. B VL - 111 IS - 8 SP - 2008 EP - 2014 AD - Applied Surface Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden, and Department of Chemistry, Emory University, Atlanta, Georgia 30322 N2 - Abstract: The consequences of including amide bonds into the structure of short-chain nonionic surfactants have been studied. Of particular interest were the possible effects of the hydrogen bonding ability of the amide group on the micellar shape. The aggregate structure and hydration of two different amide-containing surfactants, C7H15CO-NH-(CH2CH2O)4H and C7H15CO-(NH-C3H6-CO)2N(CH3)2, were investigated using NMR diffusometry (pulsed gradient spin echo NMR) as the main technique. Data from experiments on the surfactants, the hydrophobic probe molecule hexamethyldisilane (HMDS), and water were interpreted to gain information about the solution structures, and the results were compared to those on a previously studied alcohol ethoxylate surfactant of similar size, C8E4. Both of the amide-containing surfactants form small micelles within the whole investigated concentration range. At the critical micelle concentration, the aggregates are most probably spherical, and with increasing surfactant concentration there are indications of either a minor aggregate growth or agglomeration of the micelles. In addition, it was found that the presence of amide groups in the surfactant inhibits the intermicellar transport of HMDS, which occurs in the C8E4 system. From measurements on water diffusion in the three surfactant systems, it could be concluded that the surfactant hydration is higher when amide bonds are present. KW - detergents KW - diffusion KW - nmr AU - Stjerndahl, M AU - Lundberg, D AU - Zhang, H AU - Menger, FM PY - 2007/03/01/ UR - http://dx.doi.org/10.1021/jp0658492 ER -