Influence of the nature of the counterion and of hexanol on the phase behavior of the dilute ternary systems: cetylpyridinium bromide or chloride-hexanol-brine

Abstract

We also investigated the dependence of the substrate semiconductor on the electron transfer using 2 and 3 on Ti02 and Sn02. The results are summarized in Table IV. k[t for 2 and 3-Ti02 is slightly larger than that for the chemically modified system.If we compare the characteristics of electron transfer to Ti02 with that to Sn02, k[t are comparable, while the ratio of fast-decay component for Sn02 is clearly larger than that for Ti02. This leads to the conclusion that the difference of electron-transfer efficiencies between Sn02 and Ti02 is determined mainly by the ratio of adsorbed molecules having a strong electron-transfer interaction with semiconductor surfaces to those having a weak electron-transfer interaction with semiconductor surfaces to those having a weak electron-transfer interaction. This point is quite different from the electron transfer from adsorbed Ru(II) complexes to semiconductors in vacuo, in which the electron-transfer rate is strongly dependent on the semiconductor material.31 ConclusionLuminescence decays of Ru(bpy)32+ derivatives immobilized on Ti02 powder in various solvents could be fitted by the sum of (31) Hashimoto, K.; Hiramoto, M.; Sakata, T., manuscript in preparation. (32) r, was also determined separately from the decay curve measured longer time scale, so that its error is relatively small. The error limit of t; was usually less than 20%. However, it became larger when the relative weight of the fast component decreased, but did not exceed 30%. two exponentials. It could be determined that the lifetime of fast-decay component was determined mainly by the electron transfer from the excited state of the Ru(II) complexes to semiconductor. The rate constants and the quantum efficiency of the electron transfer were obtained by comparing the decay curves on semiconductor to those on insulator. The variation in quantum efficiency of the electron transfer with solvent is mainly due to the ratio of the preexponential factors of fastand slow-decay components, indicating that there are extreme configurations for the immobilized complexes on Ti02 in most solvents, and the ratio of molecule numbers of each form depends on the solvent.

Rheology of Wormlike Micelles: Equilibrium Properties and Shear Banding Transitions

“…Examples of phase diagrams reported recently in the literature are shown in Figure 6. Three ternary systems are presented: cetylpyridinium chloride-hexanol-water (at 0.2 M NaCl) [52,119,121], cetylpyridinium chloride-sodium salicylate-water (at 0.5 M NaCl) [122] and Figure 6. Phase diagrams of four wormlike micellar systems: (a) cetylpyridinium chloride, hexanol and water (0.2 M NaCl) [121]; (b) Cetylpyridinium chloride, sodium salicylate and water (0.5 M NaCl) [122]; (c) sodium dodecylsulfate, decanol and water [49,50,120]; (d) cetyltrimethylammonium bromide and water [30,124].…”

14N NMR spectra of molecular nitrogen in SDS/pentanol swollen lamellar phases

“…[31,32] Moreover, there is a multiplicity of 'bound' sites, with order parameters differing in magnitude and sign. The systems considered here are usually described as stacks of lamellae interleaved by thick (on the order of hundreds of angstrom, depending on the dilution degree) [33,34] layers of solvent, which correspond mainly to 'free' sites. The splitting observed in the spectrum is the weighted average of those pertaining to the various situations, the exchange occurring fast on the NMR timescale.…”

Thermodynamics of Amphiphilic Drug Imipramine Hydrochloride in Presence of Additives

“…The mechanism of clouding in non-ionic surfactants, however, is not yet very clear, and continues to be a source of controversy among different research groups. However, the occurrence of CP in charged micelle (i.e., ionic surfactants) solutions is not usual except under special conditions, e.g., high salt concentration (Gomati et al, 1987, Kumar et al, 2000, Panizza et al, 1998, salt free aqueous solutions of certain surfactants with large headgroups (Kumar et al, www.intechopen.com 2001, Panizza et al, 1998) or large counterions (Kumar et al, 2001(Kumar et al, , 2003, and some mixed cationic and anionic surfactant solutions (Kim & Shah, 2002. The CP appearance in these systems is explained in terms of increased hydrophobic interactions, dehydration of hydrophilic group, and formation of large aggregates/clusters.…”