Effect Of Host-guest Interaction On The Micellization Of Surfactant Mixed Systems

The host compounds such as cyclodextrin（CD）molecule and calixarene molecule can form supramolecular self-assembly systems with guest molecules such surfactants.In this thesis,the host-guest systems constructed by cyclodextrins and（or）sulfonatocalix[8]arene/green surfactants have been chosen as the main research systems.The inclusion interaction between different guest molecules and the same host compound,the effect of host-guest interaction on the micellization of surfactant mixed systems were systematically investigated.The inclusion ratios,inclusion constants for the inclusion complexes and the micellar interaction parameters of surfactant mixed systems have been calculated.1.The host-guest amphiphilic molecular systems are constructed by the host compoundβ-CD and the guest compound such as stearyltrimethyl ammonium bromide（STAB）and/or sodium N-lauroylgultamate（LAG-Na）.The relationship between the CMC values of STAB or LAG-Na or STAB/LAG-Na mixed systems and the concentration ofβ-CD is a positive linear correlation,the slope of the line is related to the molar ratio between STAB and LAG-Na.The experimental results show thatβ-CD and STAB can form the inclusion complexes mixed by 2:1 type and 1:1 type,while,β-CD and LAG-Na can form inclusion complex of1:1 type.2.The micellization of green surfactants hydrochlorate of N（α）-palmitoyl-lysine methyl ester（PLM）/alanine isopropyl ester ammonium dodecyl sulfate（ALaC₃LS）mixed system and PLM/valine isopropyl ester ammonium dodecyl sulfate（ValC₃LS）mixed system inβ-CD aqueous solutions with different concentrations have been investigated.To explore the effect of structure change of anionic surfactant on host-guest interaction and micellization.The experimental results indicate that the inclusion complex formed byβ-CD and PLM is1:1 type,while,the inclusion complexes formed byβ-CD and ALaC₃LS（or ValC₃LS）are 2:1 type and 1:1 type.The CMC value of PLM/ALaC₃LS mixed system with certain x₁ is significantly smaller than the corresponding CMC value of PLM/ValC₃LS mixed system with water as solvent,the same concentration ofβ-CD had less effect on the CMC of the PLM/ValC₃LS mixed systems.The zeta potentials of the PLM/ValC₃LS mixed systems with different x₁ have been measured to analyze the charge type of the mixed micelles.¹H NMR has been used to characterize the inclusion complexes formed byβ-CD and PLM and to explore the binding site between the host compound and guest molecule.3.The micellization of PLM/glycine isopropyl ester ammonium lauryl sulfate（GlyC₃LS）mixed system in 1 mmol·kg^-1α-CD,β-CD,γ-CD aqueous solutions have been investigated.The results indicate that,in comparison withα-CD orβ-CD,the addition ofγ-CD leads to the smallest CMC for PLM/GlyC₃LS mixed system at 298.15 K.The CMC values of ValC₃LS inα-CD,orβ-CD,orγ-CD aqueous solution at five temperatures have been measured by surface tension method.The experimental results indicate that inclusion complex formed byα-CD and ValC₃LS is 2:1 type,the inclusion complexes formed byβ-CD and ValC₃LS are 2:1 type and 1:1 type,and the inclusion complexes formed byγ-CD and ValC₃LS are 2:1 type and 1:1 type.The inclusion constant for theα-CD and ValC₃LS inclusion complex has been calculated,and the inclusion constant decreases with the increase of temperature,the inclusion process is driven by both enthalpy and entropy.The influence of the sulfonatocalix[8]arene（SC8）andβ-CD mixed host compounds on the micellization of cetyltrimethylammonium bromide（CTAB）has been investigated.There is no synergist effect between the two host compounds.4.The micellar interaction parametersβ^m of the above-mentioned mixed systems have been calculated by regular solution theory.Except for the PLM/ValC₃LS mixed system,for the other surfactant mixed systems,when water is used as solvent,theβ^m has the largest negative value,indicating the strongest synergistic effect between the surfactant molecules.When the molar ratio is 1:1,the parameter(r₁A₁₂+r₂A₂₁)/（r₁+r₂）of the dissociated Margules model is close to the model parameterβ^mof the regular solution theory,both of them can be used as the measure of the strength of synergist effect.Except for the PLM/ValC₃LS mixed system,the addition ofβ-CD leads to the weakening of the synergist effect for the other mixed systems.This is related to the competition between the inclusion interaction ofβ-CD with surfactants and the micellization of surfactants.5.In comparison with single ionic surfactants,the corresponding cationic/anionic surfactant mixed systems have larger pc₂₀ value.At the molar ratio of 1:1,there is the maximum value of pc₂₀.The pc₂₀ value of the mixed systems is negatively correlated with the concentration ofβ-CD added.At the surface of surfactant aqueous solution,the maximum excess surface concentration Γ_max is larger and A_min is smaller in the mixed systems.And at the molar ratio of 1:1,there is the maximum value of Γ_max and the minimum value of A_min.TheΓ_max value of the mixed system is positively correlated with the concentration ofβ-CD added,while,the A_min of the mixed system was negative correlation with the concentration ofβ-CD.