Novel Sugar-Based Gemini Surfactants and Their Surface Properties

A group of novel sugar-based gemini surfactants, N, N-bis(2-hydroxy-3-alkyloxylpropyl) -N, N-bis(gluconylamide)-ethylenediamine (alkyl: n-C8H17, n-C12H25, n-C14H29, n-C16H33), were synthesized and characterized. Their surface properties, including surface tension, , critical micelle concentration, CMC, maximum surface excess, ?(max), minimum area per molecule, A(min), and standard free energy of micellization and adsorption, Delta G(m)(0) and Delta G(ads)(0), were investigated. The members of this family could reduce the surface tension of water to approximately 20-25 mNm(-1) at the concentration level of 10(-5)molL(-1), considerably lower than that commonly achieved with monomeric surfactants. Their adsorption and aggregation behavior were further studied by means of dynamic light scattering and X-ray diffraction. The relationship of the aggregate size of the synthesized gemini surfactants with the length of the hydrocarbon chain and their concentration was discussed.