Study On Phase Behavior And Physicochemical Properties Of Gemini Surfactant Microemulsion System

The thesis contains five parts. Chapter I. Introduction. Chapter II. Interfacialcomposition, solubility and solubilization of microemulsions containing mixedGemini and SLS. Chapter III. Comparison of the phase behavior and solubilization ofthe microemulsions containing Gemini surfactant with those of the microemulsionscontaining traditional surfactant. Chapter IV. Synergism in microemulsions containingcationic (C12-4-C12)Br2and anionic AS(SDBS). Chapter V. Studies on the solubilitiesof the alcohol in the water and oil phases using the optimum microemulsion dilutionmethod.Chapter I. IntroductionThe definition, properties, classification and formation mechanism ofmicroemulsions were introduced. The microemulsions containing mixed surfactantswere reviewed.Chapter II. Interfacial composition, solubility and solubilizationof microemulsions containing mixed Gemini and SLSThe synergestic effect of (C12-4-C12)Br2and SLS on the interfacial composition,solubility and solubilization of oil/(C12-4-C12)Br2-SLS/butan-1-ol/aqueous NaClmicroemulsions was investigated by using an ε-β phase diagram approach.1. The middle phase would form in theX(Cs well as124C12)Brranges0to0.1a20.7to1.0. Precipitation occurs in the range0.2to0.6. The alcoholsolubility in the microemulsions(εB) would reduce significantly in comparison to thepure (C12-4-C12)Br2or SLS-based microemulsion systems. The mass fraction of thealcohol in the interfacial film (AS) also decreases.2. The solubilization capacity (SP*) is superior to the individual (C12-4-C12)Br2orSLS-based microemulsions. The maximum value of the solubilization capacity (SP*)appears at=0.7.3. As the carbon chain length of oil molecule increases, εBand ASincrease, but SP*decreases. As the NaCl contents or temperatures increases, εBand ASdecrease,while SP*increases.Chapter III. Comparison of the phase behavior andsolubilization of the microemulsions containing Geminisurfactant with those of the microemulsions containingtraditional surfactantThe effects of the isomeric alcohols on the phase behavior and thephysicochemical properties of the microemulsions containing (C12-4-C12)Br2(C12mimBr, AS)/octane/butan-1-ol (butan-2-ol,2-methyl-propan-2-ol)/aqueous NaCl(w=0.05) have been studied with an ε-β fishlike phase diagram method.1. The phase diagrams showed that the “fish body” moved upwardly as thebranched chains of the alcohols increase.2. The volumes of the middle phase of the microemulsions formed by(C12-4-C12)Br2, AS and SDBS, respectively, is in the surfactant order:(C12-4-C12)Br2>SDBS> AS.3. The solubilization ability (SP*) of the microemulsions formed by differentsurfactants is in the surfactant order:(C12-4-C12)Br2>C12mimBr>AS.4. Overall, The values of εBand ASis in the alcohol order:butan-1-ol<butan-2-ol<2-methyl-propan-2-ol. SP*is in the opposite order:butan-1-ol>butan-2-ol>2-methyl-propan-2-ol.Chapter IV. Synergism in microemulsions containing cationic(C12-4-C12)Br2and anionic AS(SDBS)The synergism of C12-4-C12)Br2with AS (or SDBS) in microemulsionscontaining octane/(C12-4-C12)Br2-AS(or SDBS)/butan-1-ol/aqueous NaCl was studied.The microemulisons would form in theX(C0.7to124Cranges0to0.1as well as12)Br21.0.As the carbon chain length of oil molecule (nc,o) increases, the solubilization ability (SP*) decreases，while ASvalues increases. And as the NaCl content ortemperature increases, the solubilization capacity (SP*) increases，while ASvaluesdecreases.Chapter V. Studies on the solubilities of the alcohol in the waterand oil phases using the optimum microemulsion dilutionmethodThe solubilities of the alcohols in water and oil phases, respectively, inmicroemulsions C12mimBr/butan-1-ol/oil/aqueous NaCl were determined with theoptimum microemulsion dilution method. The effects of the carbon chain length of oilmolecule(nc,o), the NaCl contents and temperatures on the solubilities of alcohol inwater(AW), oil(AO) and interfacial layer(AS) were discussed.As the carbon chain length of oil molecule(nc,o) increases, AW, AOand ASincrease.AW, AOand ASincrease as NaCl content increases.