Fabricate Of Steric Barrier Within Micelles For Analytical Application

Surfactants form aggregates-micelles in aqueous solutions,which can solubilize hydrophobic organic molecules due to their hydrophobic regions.The position of solubilized substances in micelles greatly affects their performance and solubilization applications.However,the position of the solubilized molecules in the micelle is mainly determined by its polarity and is difficult to change,making the solubilization results difficult to modulate.Therefore,it is important to develop a general strategy to regulate the solubilization sites of solubilized substances in micelles.Based on this,a strategy for constructing steric barrier inside micelles was proposed in this thesis.By using cationic luminescent micelles with adjustable position-tunable tetraphenylethylene（TPE）as fluorescence resonance energy transfer（FRET）donors and solubilized fluorescent molecules as FRET receptors,the precise positioning of solubilized molecules in micelles was achieved,and the feasibility of steric barrier regulation of solubilization sites was confirmed.The method has been successfully applied to micelle catalytic analysis,the regulation of complex light and the construction of micellar silica sphere fluorescence platform.1.Three derivatives of dodecyltrimethylammonium bromide(C₁₂TAB),C₈-TPE-C₄TAB,C₄-TPE-C₈TAB,and TPE-C₁₂TAB,were used to prepare aggregation induced emission（AIE）micelles,with TPE emission groups located 4,8,and 12 carbon atoms away from the quaternary ammonium head group,respectively.4,7-dithiophen-2-yl-2,1,3-benzothiadiazole（DBT）located in the inner layer of the micelle and nile red（NR）located in the palisade layer of the micelle were using as solubilized receptors,a FRET donor receptor pair is formed with the donor TPE.The results showed that DBT located in the inner layer of the micelles was solubilized to the surface layer in C₈-TPE-C₄TAB micelles,and to the palisade layer in C₄-TPE-C₈TAB micelles.NR located in the palisade layer of the micelles could be solubilized to the surface layer of C₈-TPE-C₄TAB micelles.Further introducing non-covalent steric barrier into commercial micelles also achieved controlled regulation of solubilization sites,thereby confirming that introducing steric barrier within micelles is a universal strategy for regulating the solubilization sites of micelles.2.Using the space position in C₈-TPE-C₄TAB,C₄-TPE-C₈TAB and TPE-C₁₂TAB micelles,the FRET platform was constructed by solubilizing different fluorescent molecules,obtaining a white light solution with tuable international commission on illumination（CIE）coordinates,and further silanizing to prepare fluorescent nano micellar silicon spheres.The results showed that using the same concentration of silanization reagents,the steric barrier inside the micelles can control the synthesis of micellar silica spheres with different sizes,resulting in multiple types of surface modifiable groups.In addition,silicon spheres can effectively enhance the photostability and remodeling of fluorescent micelles,showing promising analytical applications.