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1.
The present research work is associated with the fluorescence investigations of binary aqueous mixed surfactants solutions of anionic bis-sulfosuccinate gemini surfactant (BSGSMA1,8) and three different conventional surfactants—anionic viz. sodium dodecyl sulfate (SDS), cationic viz. cetyl trimethyl ammonium bromide (CTAB), and nonionic surfactant viz. Triton X 100. Steady-state fluorescence spectroscopy technique has been utilized to examine the micellization behavior of aqueous solution of pure myristyl alcohol-based BSGSMA1,8 having flexible methylene chain [(CH2)8] as spacer group. Critical micelle concentration (CMC), aggregation number (N), and micropolarity of pure and mixed surfactants systems were explored during the investigations. The results revealed the best synergism behavior of prepared gemini BSGSMA1,8 with SDS as compared to CTAB and Triton X 100. The maximum reduction in the value of pyrene intensity ratio (I1/I3) was observed for gemini and SDS mixed surfactant solution. On the other hand, the increased I1/I3 value of mixed gemini with Triton X 100 exhibited that mixed surfactant system of anionic gemini BSGSMA1,8 with non-ionic Triton X 100 is not as compact as other mixed surfactant systems. Aggregation number increased and micropolarity decreased with increased concentration of gemini surfactants. 相似文献
2.
This paper is concerned with the flow of two immiscible fluids through a porous horizontal channel. The fluid in the upper region is the micropolar fluid/the Eringen fluid, and the fluid in the lower region is the Newtonian viscous fluid. The flow is driven by a constant pressure gradient. The presence of micropolar fluids introduces additional rotational parameters. Also, the porous material considered in both regions has two different permeabilities. A direct method is used to obtain the analytical solution of the concerned problem. In the present problem, the effects of the couple stress, the micropolarity parameter, the viscosity ratio, and the permeability on the velocity profile and the microrotational velocity are discussed. It is found that all the physical parameters play an important role in controlling the translational velocity profile and the microrotational velocity. In addition, numerical values of the different flow parameters are computed. The effects of the different flow parameters on the flow rate and the wall shear stress are also discussed graphically. 相似文献
3.
Fluorescence-quenching of pyrene in micellar system has been investigated using 1,1,2,2-tetrahydroheptadecafluorodecylpyridinium
chloride (HFDePC). The new fluorocarbon quencher has a similar quenching ability as hexadecyl-pyridinium chloride (CPC) towards
pyrene in hydrocarbon micelles if only a quencher molecule is solubilized in a micelle. The fluorocarbon quencher randomly
distributed among micelles if the average occupancy number of probes per a micelle was small enough. The fluorescence behavior
of pyrene was examined for hexadecyl-trimethylammonium chloride (CTAC) and HFDePC mixtures. The variation of fluorescence
intensity gave second cmc, reflecting the micellar immiscibility of fluorocarbon and hydrocarbon surfactants. The second cmc
can be simulated by material balances of both surfactants supposing the coexistence of two kinds of mixed micelles. The fluorescence-quenching
behavior suggested the enhanced micellar immiscibility probably due to nonrandom distribution of fluorocarbon quenchers among
micelles.
Received: 13 March 1997 Accepted: 24 May 1997 相似文献
4.
The effect of small amounts of salt on the interaction between two fractions of ethyl(hydroxy)ethyl cellulose, EHEC, and
sodium dodecyl sulfate, SDS, has been investigated by means of steady-state fluorescence measurements. The two polymer fractions
display different properties in hydrophobicity expressed as different cloud points. The results are discussed in relation
to hydrodynamic (viscosity) and thermodynamic (equilibrium dialysis) properties. The micropolarity as sensed by the probe
pyrene shows that the polymers begin to interact with SDS at a lower concentration in the presence of salt. The average aggregation
numbers of polymer-bound clusters, N
p, were obtained by fluorescence-quenching data in combination with equilibrium dialysis experiments. N
p was found to increase in the presence of salt for the EHEC fraction with a high cloud point (CP). The polymer with a low
CP displays higher N
p in the presence of salt at low SDS concentrations, but exhibit lower N
p at higher SDS concentrations than in the salt-free system. The microviscosity index as determined by intramolecular excimer
formation of 1, 3-di(1-pyrenyl)propane (P3P) is highest for the lowest N
p and there is a corre-lation with N
p in the presence as well as absence of salt for both EHEC fractions. It is found that when the same fractional amount of SDS
is bound to the polymers, 10–20% of the value of saturation, the increase in macroviscosity occurs and the microviscosity
shows high rigidity.
Received: 3 March 1997 Accepted: 23 May 1997 相似文献
5.
以芘为荧光探针、二苯甲酮为猝灭剂,用稳态荧光探针法测定了合成的3种高纯的烷基苄基聚氧乙烯醚丙烷磺酸钠的临界胶束浓度、不同表面活性剂浓度下的胶团聚集数和胶团微极性.研究了链长变化对烷基苄基聚氧乙烯醚丙烷磺酸钠聚集性质的影响.考察了胶团聚集数的浓度效应,并由胶团聚集数与表面活性剂浓度关系方程外推求得了它们各自的临界胶束聚集数. 相似文献
6.
Adil Amin Aijaz Ahmad Dar Mohsin Ahmad Bhat Musarat Jan Nuzhat Rehman Mohammad Amin Mir 《Journal of Dispersion Science and Technology》2013,34(3):406-414
The present study deals with the interaction of sodium alkanoates viz. sodium acetate, sodium propionate, sodium butanoate, sodium hexanoate and sodium benzoate on the micellization of dodecylbenzyldimethylammonium chloride using conductometeric and flourscence quenching experiments carried out at 25°C. The analysis has been made through study of variation of critical micelle concentration (cmc), degree of counterion binding (β), aggregation number (N), and micropolarity with the concentration of these hydrophobic salts. The differentiation between the effects of hydrophobic and inorganic salts was made by comparing the above results with the influence of NaCl on cmc, β, and N. 相似文献
7.
Xue-Peng Liu Jie Feng Lu Zhang Qing-Tao Gong Jia-Yong Yu 《Journal of Dispersion Science and Technology》2013,34(4):568-575
A series of anionic Gemini surfactants called alkanediyl-α,ω-bis(m-octylphenoxy sulfonate) with different length of (CH2)x spacer, C8CxC8 (x = 2, 4, 6, 8), have been synthesized from 4-n-octylphenol and their basic physicochemical properties are investigated. The results indicate that they are different from cationic Gemini surfactants called alkanediyl-α,ω-bis(dimethyldodecylammonium bromide), 12-(CH2)s-12, in the literature. It is found that as the carbon atom number of the spacer increases, the cmc (critical micelle concentration) decreases gradually, and the surface area per molecule (Amin) decreases initially and then increases. The breakpoints appear at number 4 of carbon atom in the spacer. Though the length of the spacer is different for the Gemini surfactants from C8C2C8 to C8C6C8, there is no obvious change on the micropolarity. 相似文献
8.
9.
Elastic wave propagation in a cylindrical bore situated in a micropolar elastic medium with stretch 总被引:2,自引:0,他引:2
Propagation of surface elastic waves in a cylindrical bore through a micropolar elastic medium with stretch is analysed in
two cases. In the first case, the cylindrical bore is considered empty while in the second case, the bore is filled with homogeneous
inviscid liquid. In both the problems, period equations are obtained in closed form. The problem of Banerji and Sengupta [2,3]
has been reduced as a special case. Numerical calculations have been performed for a particular model and results obtained
are presented graphically. It is noticed that the effect of micropolarity on dispersion curve is significant while the effect
of micro-stretch on dispersion curve is not appreciable. 相似文献
10.
The possibilities of electron spin resonance (ESR) and electron spin resonance imaging (ESRI) for investigating the properties of the spin probes TEMPO and TEMPOL in two-phase systems have been examined in the systems water/n-octanol, Miglyol/Miglyol, and Precirol/Miglyol. Phases and regions of the phase boundary could be mapped successfully by means of the isotropic hyperfine coupling constants, and, moreover, the quantification of rotational and lateral diffusion of the spin probes was possible. For the quantitative treatment of the micropolarity, a simplified empirical model was established on the basis of the Nernst distribution and the experimentally determined isotropic hyperfine coupling constants. The model does not only describe the summarized micropolarities of coexisting phases, but also the region of the phase boundary, where solvent molecules of different polarities and tendencies to form hydrogen bonds compete to interact with the NO group of the spin probe. 相似文献