Studies And Applications Of Polyglyceryl-modified Silicone Surfactant In Aqueous Solution And Ionic Liquid

In this study, a series of polyglyceryl esters modified silicone surfactants(HL-1,2,3,4), were designed and synthesized. Herein, glyceryl and polyglyceryl esters can be acquired from renewable plants resources and considered “green” raw ingredient. Their synthesis procedure, structure, and main performance including the absorption and surface activity at air/water surface, aggregation behavior in aqueous solutions were investigated by surface tension measurements, dynamic light scattering(DLS), transmission electron microscopy(TEM) and small angle X-ray scattering(SAXS) to confirm HL-3 as optimal choice. As a result, HL-3 surfactant exhibited a comb-like structure with a linear poly(dimethylsilicone) backbone and oligomers of polyglyceryl as hydrophilic chains, and its molecular weight is 4201 g�'mol-1. Aqueous solutions of this surfactant had a low critical aggregation concentration(CAC) and low surface tension(21.5 mN·m-1), substantially lower than those reported for polyether modified silicone surfactants with a similar molecular architecture. DLS and TEM revealed self-assembled spherical micelles with a narrow size distribution(hydrodynamic radii between 50 and 90 nm). At higher concentrations(10.0 wt %), linear packing of micelles was observed, while the micelle size distribution remained similar(50 to 90 nm). SAXS data could be fitted through the use of a core-shell model and implied that the core radius remained roughly 4.3 to 6.0 nm for all solutions of the surfactant analysed. The origin of its curious aggregates behaviour is attributed to hydrogen bonding, steric effects and the directionality of bond angle from the polyglyceryl block of this novel class of silicone surfactant. At higher concentration(over 10.0 wt %), a full structural characterisation of the aggregates formed by HL-3 silicone surfactant in water and variations with surfactant concentration were evaluated by polarized microscope and rheology. The system turns into Lamellar and hexagonal liquid crystal phase, and bright birefringence and increasing viscosity can be observed under polarizer and rheology for the phases with 30.0 wt %. The phases with 30.0 wt % to 50.0 wt % are Lamellar liquid crystal and with increasing HL-3 content, the hexagonal liquid crystal phase can be formed. Rheological experiments concluded that HL-3 aqueous solutions behave as non-Newtonian fluid and the characteristics of elasticity, display the elastic liquid crystal behavior over 30 wt % concentration.HL-3/1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide[EMIM][NTf2] binary system and HL-3/[EMIM][NTf2]/silicone oil ternary system were prepared, and similar testing methods and measurements were carried out to investigate the surface activity and the phase behavior in HL-3/[EMIM][NTf2] system. The results revealed that HL-3 can reduce the surface tension remarkably to 23.4 mN·m-1 and form the micelles at different concentrations. Meanwhile this surfactant had a higher critical aggregation concentration(CAC), the saturation surface excess concentration Γmax and the area per molecule Amin compared to HL-3 in water due to weaker molecular interaction between HL-3 and [EMIM][NTf2] caused by polarization force and hydrogen-bonding. By introducing silicone oil, microemulsions consisting of [EMIM][NTf2],silicone surfactant HL-3 as emulsifier, and silicone oil as continuous phase were prepared, and the phase diagram of the ternary system was investigated and the UV-vis absorbance spectra of MO were used to study the characteristics and the compositions of [EMIM][NTf2] in silicone oil(IL/O) microemulsions. The results indicated that, with the addition of the [EMIM][NTf2] into the HL-3/silicone oil system,the IL pools began to form that was implied by the absorption maximum max? red-shift in the absorption spectra of MO that is also an indication of the polarity of the microenvironment where is is located. When the the absorption maximum max? was constant that demonstrated the polarity of the IL pools didn’t change any more and the IL pools size grows from 25 to 167 nm. These results are essential to the use of IL/O microemulsions as solvent systems in the nanomaterials preparation. In this work, Au/TiO2 photocatalyst was prepared successfully by utilizing [EMIM][NTf2] solubility and compatibility to metal salt in ternary microemulsion system.The basic properties of HL-3 silicone surfactant were measured, and the measurement results showed that HL-3 has a good spreading ability, and the wettability is better than hydrocarbon surfactant(AEO-7) and increases with the concentration. As a silicone emulsifier, it can emulsify silicone oil very well but not much for paraffin oil, also HL-3 is not good at the foaming and anti-foaming.A multiple functional anti-aging and moisturizing cream was made by adding HL-3 silicone surfactant into the placebo cream, and the consumer evaluation and clinical testing were carried out to compare the efficacy of the placebo cream with and without HL-3, and the measurement of skin spots image with Photomax Pro systems, total wrinkle area with Visioline VL650 and full face image with Visia-CR(Canfield). The results indicated that HL-3 cream was formulated to form double-layer liquid crystal structure, and can improve the penetration and utilization of effective actives significantly, the HL-3 cream treated side showed statistically significant effect on skin whiteing, anti-spot, anti-wringle in the whole study compared to the placebo cream side.