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

The conductivity (κ), surface tension (γ), viscosity (η), dynamic light scattering (DLS) and Krafft temperature (KT) measurements of aqueous dodecyltrimethylammonium bromide (DTAB) and di(dodecyldimethylammonium bromide) (12-2-12) with poly (amidoamine) (PAMAM) dendrimers have been carried out at 25 °C. From the κ data, the apparent critical micelle concentration (acmc) for 12-2-12 and DTAB in aqueous PAMAM and complex forming concentration of PAMAM (CS) were computed. Both acmc and CS increased with the increase in [PAMAM] and [12-2-12], respectively. The γ studies indicated a considerable decrease in the γ value for 12-2-12 in aqueous 0 and 1 G than 0.5 and 1.5 G. However, similar γ behavior of DTAB in aqueous PAMAM did not discriminate among various generations. From η studies, the intrinsic viscosities of 12-2-12 ([η]12-2-12) and DTAB ([η]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.