Dodecyltrimethylammonium and Di(dodecyldimethylammonium) bromides interactions with poly (amidoamine) dendrimer

The conductivity (kappa), surface tension (gamma), viscosity (eta), dynamic light scattering (DLS) and Krafft temperature (K-T) measurements of aqueous dodecyltrimethylammonium bromide (DTAB) and di(dodecyldimethylammonium bromide) (12-2-12) with poly (amidoamine) (PAMAM) dendrimers have been carried out at 25 degreesC. From the K data, the apparent critical micelle concentration (acmc) for 12-2-12 and DTAB in aqueous PAMAM and complex forming concentration of PAMAM (C-S) were computed. Both acme and C-S increased with the increase in [PAMAM] and [12-2-12], respectively. The gamma studies indicated a considerable decrease in the gamma value for 12-2-12 in aqueous 0 and 1 G than 0.5 and 1.5 G. However, similar gamma behavior of DTAB in aqueous PAMAM did not discriminate among various generations. From 17 studies, the intrinsic viscosities of 12-2-12 ([eta](12-2-12)) and DTAB ([eta](DTAB)) for 12-2-12 and DTAB in aqueous PAMAM were computed. Both values were higher for 12-2-12 than for DTAB suggesting stronger association in 12-2-12 + PAMAM complex. (C) 2004 Elsevier B.V. All rights reserved.