| Surfactants are an important class of amphiphilic molecules that can significantly reduce the surface tension of water.The study of their aggregation behaviors and surface properties has always been an important part of colloid and interface chemistry.In actual production,the commonly used compounding method produces synergistic effects and improves economic benefits.The vast majority of known surfactant complex systems use hydrocarbon surfactants and use water as the solvent.Most of the non-aqueous solvents are organic solvents,with high toxicity and low safety.There is an urgent need to develop green and environmentally friendly non-aqueous solvent surfactant complex systems.Silicone surfactants are a new class of surfactant,which have the advantages of excellent surface activity,high temperature resistance,good biocompatibility,etc.But the shortcoming of easy hydrolysis under acid or base catalysis limits their application in research.At present,little is known about the aggregation behaviors and surface properties of its complex systems,and further researches are needed.In this paper,polyether modified trisiloxane surfactant was selected as the main research object,and two parts of research are mainly carried out:One part is the aggregation behaviors of silicone surfactant/lithium dodecyl sulfate complex system in water and ionic liquid ethylamine nitrate,aiming to broaden the cognition of silicone surfactants complex system.And using the "green solvent" "ionic liquid to build a green and environmentally friendly non-aqueous solvent complex system;Another part is to prepare an emulsion using this silicone surfactant,water and polymerizable oil,and to construct a surfactant-enhanced double-network porous silicone elastomer by utilizing the easy hydrolysis property of silicone surfactant.The thesis mainly consists of the following parts:In the Chapter Ⅰ,We introduced the basic concepts,properties and aggregate formation theory of surfactants;Briefly introduced the classification and properties of silicone surfactants and introduced the research progress of trisiloxane surfactants in detail;Systematically introduced the research progress of the aggregation behaviors of amphiphilic molecules in ionic liquids and briefly introduced silicone elastomers.Finally,we introduced the idea;research content and significance of this thesis.In the Chapter Ⅱ,we investigated the aggregation behaviors of polyether-modified trisiloxane/lithium dodecyl sulfate(LDS)surfactant complex system in water and ionic liquid ethylamine nitrate(EAN)in detail.Surface tension test is an important means to understand the basic properties of surfactants.Analysis of the surface tension curves of the water system show that:when the molar ratio of LDS not exceed 50%,the values of the lowest surface tension(γcmc)are slightly lower than that of either surfactant,indicating that the two surfactants have a certain synergistic effects;In addition,neither the values of critical micelle concentration(cmc)nor γcmc changed with the increase of LDS content.When the molar ratio of LDS is greater than 50%,the values of γcmc are higher than that of the silicone surfactant but much lower than that of LDS.The values of cmc and γcmc increase with the increase of LDS content.In the EAN system,the values of γcmc in different surfactanst ratios are higher than that of silicone surfactant,but much lower than that of LDS,and the cmc values significantly lower than that of either surfactant.Our study is expected to deepen the understanding.of the aggregation behaviors of silicone surfactant complex systems in aqueous/non-aqueous solvents.In the Chapter Ⅲ,we formulated a water-in-oil(W/O)emulsion using polyether-modified trisiloxane surfactant,acrylate-modified silicone oil,and water.We prepared porous silicone elastomers by using the emulsion polymerization method and removing the aqueous phase.For a long time,the hydrolytic stability of silicone surfactants is poor,and silanol compounds are produced by rapid hydrolysis under acid or base catalysis.This phenomenon limits their large-scale application.Under the catalysis of acid or base,silanol compounds can undergo polycondensation reaction.We make clever use of this feature:polyether-modified trisiloxane can both act as surfactant to prevent phase separation and participate in the formation of cross-linked networks as polymerizable segments.The trisiloxane segment and the polydimethylsiloxane segment in the emulsion undergo acid-catalyzed hydrolysis and alkali-catalyzed polycondensation two-step reactions to form a flexible cross-linked network.Then,through UV-initiated polymerization,the acrylate segment can form a cross-linked network,and after drying and removing water,a double-crosslinked porous silicone elastomer can be obtained..Our silicone elastomer can withstand a high temperature of 370℃,which is higher than the decomposition temperature of most silicone elastomers reported so far.In addition,the preparation process of acrylate-modified silicone oil is mature,it is cheap and easy to obtain,which significantly reduces the production cost of the porous silicone elastomer. |
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