A bolaform amphiphile(BP-15) bearing biphenyl group and long spacers of alkyl chains was synthesized. In-situ AFM studies indicate that the amphiphile can form two kinds of surface aggregates with different morphologi...A bolaform amphiphile(BP-15) bearing biphenyl group and long spacers of alkyl chains was synthesized. In-situ AFM studies indicate that the amphiphile can form two kinds of surface aggregates with different morphologies depending on solution concentration: short-range ordered cylindrical surface micelles at the lower concentration and flat domains at the higher concentration. These results agree well with the two critical micelle concentrations in bulk solution as determined by the concentration-dependent conductivity.展开更多
We use a diamond anvil cell for the first time to investigate the Raman spectra of an aqueous micellar solution of hexadecyltrimethylammonium bromide (CTAB) at pressures up to 3.85 GPa. The pressure-induced phase tr...We use a diamond anvil cell for the first time to investigate the Raman spectra of an aqueous micellar solution of hexadecyltrimethylammonium bromide (CTAB) at pressures up to 3.85 GPa. The pressure-induced phase transition between the micellar and coagel phases is found to occur at 0.64 GPa and 60℃. This phase transition has a pressure hysteresis, and thus exhibits the first-order phase transition properties. Further experimental results show that although the structure of the coagel phase is similar to that of the CTAB crystal, the interchain distance is slightly larger in the coagel phase than that in the CTAB crystal.展开更多
文摘A bolaform amphiphile(BP-15) bearing biphenyl group and long spacers of alkyl chains was synthesized. In-situ AFM studies indicate that the amphiphile can form two kinds of surface aggregates with different morphologies depending on solution concentration: short-range ordered cylindrical surface micelles at the lower concentration and flat domains at the higher concentration. These results agree well with the two critical micelle concentrations in bulk solution as determined by the concentration-dependent conductivity.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20673048 and 20773043, NCET-06-0313 PCSIRT (IRT0625), the National Basic Research Programme of China under Grant No2005CB724400.
文摘We use a diamond anvil cell for the first time to investigate the Raman spectra of an aqueous micellar solution of hexadecyltrimethylammonium bromide (CTAB) at pressures up to 3.85 GPa. The pressure-induced phase transition between the micellar and coagel phases is found to occur at 0.64 GPa and 60℃. This phase transition has a pressure hysteresis, and thus exhibits the first-order phase transition properties. Further experimental results show that although the structure of the coagel phase is similar to that of the CTAB crystal, the interchain distance is slightly larger in the coagel phase than that in the CTAB crystal.