Morphological Evolution of Self-Assembled Sodium Dodecyl Sulfate/Dodecyltrimethylammonium Bromide@Epoxy-β-Cyclodextrin Supramolecular Aggregates Induced by Temperature

Bio-based cyclodextrins(CDs)are a common research object in supramolecular chemistry.The special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interaction with guest molecules.The different forms of supramolecular self-assemblies can be transformed into each other under certain conditions.The regulation of supramolecular self-assembly is not only helpful to understand the self-assembly principle,but also beneficial to its application.In the present study,the self-assembly behavior of epoxy-β-cyclodextrin(EP-β-CD)and mixed anionic and cationic surfactant system(sodium dodecyl sulfate/dodecyltrimethylammonium bromide,SDS/DTAB)in aqueous solution was studied.Morphological and particle size characterization found that the SDS/DTAB@EP-β-CD complex,as the basic building unit,self-assembled into worm-like micelles at lower temperatures and vesicles at higher temperatures.Nuclear magnetic resonance(NMR)and Fourier transform infrared spectroscopy(FT-IR)analysis revealed that the driving force for the formation of vesicles and worm-like micelles was the hydrogen bonds between EP-β-CD molecules,while water molecules played an important role in promoting vesicle formation between SDS/DTAB@EP-β-CD units.Herein,the mechanism of the morphologic transformation of SDS/DTAB@EP-β-CD supramolecular aggregates induced by temperature was elucidated by exploring the self-assembly process,which may provide an excellent basis for the development of delivery carriers.

Detection of phthalates migration from disposable tablewares to drinking water using hexafluoroisopropanol-induced catanionic surfactant coacervate extraction

Hexafluoroisopropanol(HFIP)-induced sodium dodecyl sulfate/dodecyltrimethylammonium bromide(SDS/DTAB) catanionic surfactant coacervate extraction method coupled with high performance liquid chromatography(HPLC) was used to detect the migration of phthalates from disposable tablewares to drinking water. The concentration factors are larger than 82 and extraction recoveries over 53% for water samples spiked with 100 or 200 ng/m L phthalates. Limit of detection is in the range of 1.0–2.6 ng/m L.Good linearity with correlation coefficients larger than 0.9985 is obtained in the concentration of20–1500 or 40–3000 ng/m L. Relative recoveries are from 82.4% to 123.6% for water samples spiked with30/60, 250/500, and 1500/3000 ng/m L phthalates, respectively. Relative standard deviations(RSDs) are0.4%–7.4% for intraday precision(n = 5) and 0.6%–7.8% for interday precision(n = 3). Four of studied phthalates are found in the drinking water samples prepared from four kinds of tablewares.