Formamide, a water substitute. 12. Krafft temperature and micelle formation of ionic surfactants in formamide

Abstract

eV for an indirect transition, and 1.24 eV for a direct transition are close to the reported single value of 1.21 eV (again, the mode was not assigned).The occurrence of both an indirect and direct transition is common for the CdIn2VI4 family of materials, and the difference between £ind and £d has been reported to be 0.1 eV for CdIn2Te4.12 Our value of 0.08 eV is close to the 0.1 eV value. We also obtained a value of 0.16 eV for the difference between £ind and £d for p-Hg!n2Te4. It seems that the difference between £ind and £d decreases from 0.22 eV for CdIn2Se4 to 0.08 eV for CdIn2Te412 and increases from 0.08 eV for CdIn2Te4 to 0.16 eV for HgIn2Te4.The Mott-Schottky plot intercept value of -0.48 V was close to that of the onset of photocurrent (-0.53 V, see Table I); therefore, the open circuit photovoltage is expected to be ~0.6 V (£redox = -1.09 V). Considering a band gap value of 1.20 eV (0.9 eV for HgIn2Te4) and an analysis parallel to that given for p-HgIn2Te4 above, the valence band would be located at -0.4 V (-0.6 V for HgIn2Te4) and the conduction band near -1.6 V (-1.5 V for HgIn2Te4).The photocurrent onset and the maximum power efficiency in[Cr(III)EDTA]' with monochromatic light irradiation were close to that in Fe(III)TEA complex solution, but the maximum power efficiency in [Cr(III)EDTA]' with polychromatic light irradiation was less than that in Fe(III)TEA complex solution (the reason for this is given above). Therefore, the Fe(III)TEA complex solution is a preferred one for both p-HgIn2Te4 and p-CdIn2Te4 electrodes.

SANS studies of the effects of surfactant head group on aggregation properties in water/glycol and pure glycol systems

“…Micelle and liquid crystal formation has been reported in solvents such as ethylene glycol (EG) [15], glycerol [2,16,[26][27][28], formamide [4,[17][18][19][20][21]29], and hydrazine [22,23]. The glycol solvents have high cohesive energies and dielectric constants (ε r (EG) = 53 and ε r (PG) = 30), and hydrogenbonding properties, which are believed to be essential requirements for promoting micellization [24].…”

Thermodynamic properties of micellization of sodium dodecyl sulfate in binary mixtures of ethylene glycol with water

“…There has recently been much research dealing with the effects of nonaqueous polar solvents on the formation of cationic micelles (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Micel!e or liquid crystal formation has been reported to occur in such solvents as hydrazine (3,4), glycerol (5,6), ethylene glycol (7,8), and formamide (9)(10)(11)(12)(13)(14)(15)(16)(17)(18), where all of the aforementioned solvents have high cohesive energy, dielectric constant, and a high degree of hydrogen bonding. Evans and co-workers (19) have indicated that the ability of a solvent to form hydrogen bonds is a necessary condition of micelle formation.…”

Growth of gold nanorods in gelled surfactant solutions

“…In this experiment, the OTAB appears to be a coagel phase in case A. In case B, the OTAB solution exhibits the micellar structure (35°C), although the Krafft point of OTAB is reported as 38°C [24]. This is because the relaxation time to a coagel structure is quite longer than the observation time when the temperature of the solution (case B; 35°C) is close to the Krafft temperature.…”