Synthesis, Surface Property and Antimicrobial Activity of Cationic Gemini Surfactants Containing Adamantane and Amide Groups

Abstract

Abstract A series of novel cationic gemini surfactants, namely 1,3‐adamantanedicarboxylic acid bis(alkyldimethyl‐3‐ammoniopropyl amide) dibromide designated as [Ad‐2(amC n )] ( n = 12, 14, 16), containing adamantane, two amide groups, and two hydrocarbon chains, were synthesized from 1,3‐adamantanedicarboxylic acid. The surface‐active properties of the surfactants were investigated through surface tension and electrical conductivity measurement. A series of thermodynamic parameters such as standard free energy , enthalpy , and entropy of micellization were evaluated from electrical conductivity measurements in the temperature range from 288 to 308 K. The micellization for [Ad‐2(amC n )] is entropy‐driven at low temperature and enthalpy‐driven at high temperature. Further, the antimicrobial activity of the synthesized gemini surfactants against both Gram‐positive and Gram‐negative bacteria was also investigated, and this study showed that the compound [Ad‐2(amC 12 )] has excellent antibacterial activity against all studied bacteria.