| Organic silicon gemini surfactants have attracted wide attention of many researchers beacause they possess both advantages of silicone surfactants?good wetting ability,emulsion power and low toxicity?and gemini surfactants?lower critical micelle concentration,higher surface activity?.Epoxy-modified polyether ploysiloxane was synthesized by polyethylene glycol diglycidyl ether and polydimethylsiloxane.Then,six kinds of quaternary ammonium organic silicon gemini surfactants(Cm-PSi15-Cm)with different hydrophobic chains length?m=8,10,12,14,16,18?and five kinds of quaternary ammonium organic silicon gemini surfactants(C12-PSix-C12)with different siloxane chains length?x=0,15,30,100,800?were synthesized by quaternarization of EPEPS with N,N-dimethyl long chain alkyl amine.The synthesis process of quaternary ammonium organic silicon gemini surfactants was optimized by using single-factor experiment and its performances were studied.Finally these surfactants were applied in the leather industry.The importance of hydrophobic chains length on the physicochemical and antimicrobial activities of Cm-PSi15-Cm was revealed in detail.Experimental results showed that surface activity,wetting performance,emulsion stability,foamability,antimicrobial activities of Cm-PSi15-Cm increased initially and then decreased with the increase of hydrophobic chains length.The thermodynamic parameters results of Cm-PSi15-Cm showed that changing process of micellization were an entropy-driven—enthalpy-driven—entropy-driven with the increase of hydrophobic chains length.The micelles aggregation number of C12-PSi15-C12 was greater than C8-PSi15-C8 at the same concentration by using steady-state fluorescence measurements.The changing process of aggregation behavior of C12-PSi15-C12 was micelles—spherical vesicles—rod-like vesicles—dumbbelllike vesicles —string of dumbbell-like vesicles with concentration increasing.The effect of spacer length on the physicochemical and antimicrobial activities of C12-PSix-C12 was revealed in detail.Experimental results showed that surface activity,wetting property and emulsion stability of C12-PSix-C12 increased initially and then decreased with the increase of siloxane spacer length.Among of all the surfactants,C12-PSi0-C12 possessed the strongest foamability and antimicrobial activities.Antibacterial properties and fiber dispersion of skin were best using C12-PSi15-C12 treatment and having less damage on collagen fiber in the soaking process.Colour fastness and dye absorbing of skin were best using C12-PSi0-C12 treatment in the dyeing process. |
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