We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mech...We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.展开更多
Wettability alteration of carbonate reservoirs from oil-wet to water-wet is an important method to increase the efficiency of oil recovery. Interaction between surfactants and polymers can enhance the effectiveness of...Wettability alteration of carbonate reservoirs from oil-wet to water-wet is an important method to increase the efficiency of oil recovery. Interaction between surfactants and polymers can enhance the effectiveness of surfactants in EOR applications. In this study, the interaction of polyethylene glycol(PEG) with an ionic surfactant, sodium dodecyl sulphate(SDS),is evaluated on an oil-wet carbonate rock surface by using contact angle measurements. The results reveal that wettability alteration of carbonate rocks is achieved through PEG/SDS interaction on the rock surface above a critical aggregation concentration(CAC). The behaviour of PEG/SDS aqueous solutions is evaluated using surface and interfacial tension measurements. Furthermore, the effect of PEG and SDS concentrations and impact of electrolyte addition on PEG/SDS interaction are investigated. It is shown that electrolyte(NaCl) can effectively decrease the CAC values and accordingly initiate the wettability alteration of rocks. Moreover, in a constant SDS concentration, the addition of NaCl leads to a reduction in the contact angle, which can also be obtained by increasing the aging time, temperature and pre-adsorption of PEG on the rock surface.展开更多
采用硫磺素T(Th T)荧光分析方法测定了乳清蛋白在p H 2.0,反应温度分别为343,353,358,363 K及383 K条件下纤维形成的临界聚集质量浓度(CAMC)。为了提高测定的准确性,采用不同的搅拌速度,结果表明,纤维形成的CAMC随反应温度的变化非常小,...采用硫磺素T(Th T)荧光分析方法测定了乳清蛋白在p H 2.0,反应温度分别为343,353,358,363 K及383 K条件下纤维形成的临界聚集质量浓度(CAMC)。为了提高测定的准确性,采用不同的搅拌速度,结果表明,纤维形成的CAMC随反应温度的变化非常小,CAMC接近0.44 g/(100 m L)。用自组装的热力学原理分析纤维形成的过程,结果显示,乳清蛋白在p H 2.0和测定的反应温度条件下,纤维的形成是熵驱动的过程。利用透射电子显微镜观察不同乳清蛋白质量浓度对纤维性形态的影响,结果证实了Th T荧光分析测定的CAMC结果。展开更多
The aggregation behavior of dodecyl 1-pyrenylmethyl ether was studied in dioxane-water mixture solvents by fluorescence techniques. The labeled pyrenyl group was effective in monitoring the polarity change of its envi...The aggregation behavior of dodecyl 1-pyrenylmethyl ether was studied in dioxane-water mixture solvents by fluorescence techniques. The labeled pyrenyl group was effective in monitoring the polarity change of its environment during aggregation processes. Based on the structural effects such as chain-length effect, self-coiling effect, and branch-group effect on the polarity of the probe environment, the structure features of aggregates were discussed and have been used to interpret the effect of the structural features on the aggregates formed by three cholesteryl esters and three long chain alkanes.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50573065 & 50873086)the Natural Science Foundation of Zhejiang Province (Grant No. Z406018)
文摘We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.
文摘Wettability alteration of carbonate reservoirs from oil-wet to water-wet is an important method to increase the efficiency of oil recovery. Interaction between surfactants and polymers can enhance the effectiveness of surfactants in EOR applications. In this study, the interaction of polyethylene glycol(PEG) with an ionic surfactant, sodium dodecyl sulphate(SDS),is evaluated on an oil-wet carbonate rock surface by using contact angle measurements. The results reveal that wettability alteration of carbonate rocks is achieved through PEG/SDS interaction on the rock surface above a critical aggregation concentration(CAC). The behaviour of PEG/SDS aqueous solutions is evaluated using surface and interfacial tension measurements. Furthermore, the effect of PEG and SDS concentrations and impact of electrolyte addition on PEG/SDS interaction are investigated. It is shown that electrolyte(NaCl) can effectively decrease the CAC values and accordingly initiate the wettability alteration of rocks. Moreover, in a constant SDS concentration, the addition of NaCl leads to a reduction in the contact angle, which can also be obtained by increasing the aging time, temperature and pre-adsorption of PEG on the rock surface.
文摘采用硫磺素T(Th T)荧光分析方法测定了乳清蛋白在p H 2.0,反应温度分别为343,353,358,363 K及383 K条件下纤维形成的临界聚集质量浓度(CAMC)。为了提高测定的准确性,采用不同的搅拌速度,结果表明,纤维形成的CAMC随反应温度的变化非常小,CAMC接近0.44 g/(100 m L)。用自组装的热力学原理分析纤维形成的过程,结果显示,乳清蛋白在p H 2.0和测定的反应温度条件下,纤维的形成是熵驱动的过程。利用透射电子显微镜观察不同乳清蛋白质量浓度对纤维性形态的影响,结果证实了Th T荧光分析测定的CAMC结果。
基金Project supported by the National Natural Science Foundation of China （No, 20272078） and Shanghai Municipal Science and Technology Commission （No. 03JC14083）.Dedicated to Professor Xikui Jiang on the occasion of his 80th birthday.
文摘The aggregation behavior of dodecyl 1-pyrenylmethyl ether was studied in dioxane-water mixture solvents by fluorescence techniques. The labeled pyrenyl group was effective in monitoring the polarity change of its environment during aggregation processes. Based on the structural effects such as chain-length effect, self-coiling effect, and branch-group effect on the polarity of the probe environment, the structure features of aggregates were discussed and have been used to interpret the effect of the structural features on the aggregates formed by three cholesteryl esters and three long chain alkanes.
