Synthesis And Properties Of Glucose-based Gemini Surfactants

Surfactants are widely used in industrial,agricultural production and many other fields.With the increasing demands for environmental protection and sustainable development,it has become the trend of our times to produce eco-friendly surfactants from natural resources.Sugar-based surfactants,an important representative,have aroused great attention due to the fact that they are biodegradable,very mild to the skin,and are derived from renewable sources.Gemini surfactants have more superior properties than conventional surfactants,such as higher surface activity and very low cmc,etc.In recent years,combined with both advantages,glucose-based gemini surfactants have attracted great attention.In this paper,two types of glucose-based gemini surfactants,glucosamide-type and glucosyl tertiary amine type,were synthesized from D-glucose,ethylenediamine,epichlorohydrin,D-(+)-glucono-?-lactone and long chain fatty alcohol,and characterized.Their surface properties were studied by surface tension measurement,dynamic light scattering(DLS)and x-ray Diffraction(XRD).1.The gemini surfactants were synthesized via three steps: Long chain fatty alcohol reacted with epichlorohydrin to produce alkyl glycidyl ethers,which then reacted with ethylenediamine to produce compound N,N'-bis(2-hydroxy-3-alkoxypropyl)ethylenediamine;Finally the ethylenediamine derivatives reacted with D-(+)-glucono-?-lactone in Me OH to produce the glucosamide gemini surfactants.The products were characterized by IR and NMR.2.The surface properties,including surface tension,?,critical micelle concentration,cmc,maximum surface excess,?max,minimum area per molecule,Amin,and standard free energy of micellization and adsorption,?G0mic,?G0ads,were investigated.Their adsorption and aggregation behavior were further studied by means of DLS and XRD.Results indicated that members of this family could reduce the surface tension of water to approximately 20-25 m N/m at the concentration level of 10-5 mol/L,considerably lower than that commonly achieved with monomeric surfactants.The cmc values decreased with the increase of the hydrocarbon chain length.Both of ?G0mic and ?G0ads are negative,among which ?G0ads is bigger in absolute value,indicating that aggregation and adsorption are spontaneous process,while the adsorption trend is greater.DLS showed vesicles formed with a diameter of 79.6-237.3 nm at a concentration of 0.06-0.2 mmol/L.The bilayer thickness of spontaneous vesicle produced by 7a and 7b were 27.8 and 33.2 ? respectively by XRD.3.Glucosamine was synthesized with anhydrous glucose and ethylenediamine,which then reacted with prepared alkyl glycidyl ether to produce glucose-based gemini surfactant.The product was characterized by IR and NMR.4.The surface activities,aggregation properties in aqueous solution,foam performance,wetting and emulsifying properties of the gemini surfactant were investigated through surface tension measurement,DLS and XRD.It was showed that this type of surfactants had excellent surface activity,of which cmc down to 3.16 × 10-5 mol/L for 10 c,and ?cmc down to 22.1 m N/m for 10 b.?G0mic and ?G0ads are negative,indicating that these processes are spontaneous.DLS showed vesicles can be formed at a concentration of 0.08-0.4 mmol/L,and its particle size increased with the increase of hydrocarbon chain and concentration.