Ultrasonic behaviour of aqueous solutions of polyethylene glycols on the temperature of adiabatic compressibility minimum of water

Sailaja, D.; Raju, K. N.; Devi, G. S. Santha; Subbarangaiah, K.

doi:10.1016/s0014-3057(97)00217-6

Cited by 12 publications

(4 citation statements)

References 10 publications

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“…1 and Table 1). The decreases in κ with the increase in the amount of glycol additive have already been observed for similar systems and are attributed to the decrease in the relative permittivity (ε) and increase in the viscous drag (η) of the medium (17)(18)(19). Interestingly, the increase in the κ value with the increase in the number of repeating units (Fig.…”

Section: Resultssupporting

confidence: 68%

Hydrophobic hydration of cationic mixed micelles by alkoxyethanols in aqueous media

Bakshi

Doe

2000

J Surfact & Detergents

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The conductances of hexadecylpyridinium chloride (HPyCl) + tetradecyltrimethylammonium bromide (TTAB) mixtures over the entire mole fraction range of HPyCl (α HPyCl ) were measured in aqueous binary mixtures of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether containing 10 to 30 wt% additive in their respective binary mixtures at 30°C. Each conductivity curve showed a single break over the whole mole fraction range of HPyCl + TTAB mixtures. From the break in the conductivity curve, various micellar parameters were calculated and the results were discussed on the basis of alkoxyethanol's hydrophobic hydration of the mixed micelle. The micellar parameters of HPyCl, TTAB, and of their mixtures showed a strong dependence both on the amount and on the number of repeating units of ethylene and diethylene glycol derivatives. The hydrophobic hydration was considerably higher in the case of diethylene glycol derivatives owing to the presence of an extra ether oxygen. An evaluation of the non-ideality in the HPyCl + TTAB mixtures in the presence of additives revealed that alkoxyethanols reduce the unlike surfactant monomer interactions in order to form the mixed micelles in comparison to those in pure water. It has also been observed that such interactions systematically decrease with an increase in the number of repeating units from monomethyl ether to monobutyl ether, both in the case of ethylene and diethylene glycol derivatives.

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Section: Resultssupporting

confidence: 68%

Hydrophobic hydration of cationic mixed micelles by alkoxyethanols in aqueous media

Bakshi

Doe

2000

J Surfact & Detergents

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“…18 Thus the ability to break down the structure of water increases with PEG molecular weight. 22 In the cosolventrich region, above the PEG 400 and acetone intersection, solvation is dominated by the properties of the cosolvent. One reason for the higher solubility in acetone than PEG may be that PEG 400 23 has a greater specific H-bonding and lower polar component to its partial solubility parameters than acetone.…”

Section: Resultsmentioning

confidence: 99%

“…The bilinear model can be explained by the nonideality of PEG and acetone solutions in water arising from extensive intermolecular H-bonding. , Solvent properties vary between the water-rich and cosolvent-rich solutions as a result of specific and nonspecific solvation interactions. , The more effective solubilization by PEG than acetone at low mole fractions was understood on the basis that in breaking down the structure of water, each individual ethylene oxide unit behaves as a small molecular weight solute in its interactions with water . Thus the ability to break down the structure of water increases with PEG molecular weight . In the cosolvent-rich region, above the PEG 400 and acetone intersection, solvation is dominated by the properties of the cosolvent.…”

Section: Resultsmentioning

confidence: 99%

Crystallization and Crystallinity of Fluticasone Propionate

Murnane

Marriott

Martin

2008

Crystal Growth & Design

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Solubilization of fluticasone propionate (FP) was effected using aqueous solutions of (i) different grades of poly(ethylene glycol) (PEG), (ii) methanol, and (iii) acetone to enable antisolvent crystallization by the addition of water. The solubility of FP in acetone was significantly higher than in PEG 400 or PEG 6000, and FP solubility was observed to be nonideal in either cosolvent. Crystallization of FP was instantaneous upon addition of water as antisolvent, with nucleation occurring during the mixing phase. The smallest crystals were produced in all cases from PEG solvents, which was attributed to a greater degree of nucleation and microcrystals of a size-range were produced. Crystals produced from PEG solvents also displayed a resistance to agglomeration and Ostwald ripening, which was observed to affect the morphology of FP crystallized from either methanol or acetone by the addition of water. In spite of the very rapid kinetics of solid formation, FP crystallized as the stable Form I polymorph from PEG 400 and PEG 6000. Conversely, mechanical milling of highly crystalline particles resulted in the generation of disorder in the crystals, which was apparent from surface dynamic vapor sorption analysis. The generation of FP microcrystals with a small size range from environmentally benign PEG solvents as the stable crystalline form represents an improvement over current crystallization and micronization techniques for the production of inhalable FP

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“…The (-CH 2 CH 2 O-) group contains both the hydrophobic hydrocarbon part (-CH 2 CH 2 -) and hydrophilic oxygen having lone pair of electrons capable of forming hydrogen bonds with water molecules. [41] This (-CH 2 CH 2 O-) group thus would not be truly hydrophobic in nature. Moving from EG to DEG, TEG, and TeEG as the number of (-CH 2 CH 2 O-) group increases, the hydrophobic contact between (-CH 2 CH 2 -) groups become more favorable that results in the reduction of the (-CH 2 CH 2 -) area which is accessible to water.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic Study of a Cationic Surfactant in Aqueous Solution Containing Ethylene Glycol and Its Oligomers: Effect of Number of Ethereal Oxygen Atoms in Glycols Molecule

Chavda

Bahadur

2013

Journal of Dispersion Science and Technology

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Effect of glycols viz., ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG) and tetraethylene glycol (TeEG) on micellization parameter of cationic surfactant tetradecyletrimethyl ammonium bromide (TTAB) was examined by means electrical conductivity measurements. The critical micelle concentration (CMC), degree of counterion dissociation (a) and Gibbs energy of micellization (DG m ) as well as Gibbs energy of transfer (DG t ) of surfactant tail from bulk phase to micellar phase as a functions glycol concentration at 303.15 K were evaluated. In ordered to obtain enthalpy (DH m ) and entropy (DS m ) of micellization, CMCs were determined in 10.0% of glycols in temperature range from 303.15 K to 323.15 K. Thermodynamic parameters of the micellization reveal that effectiveness of glycols to reduce micellization increases with concentration and with number of ethereal oxygen, [-O-] n in glycol molecule. INTRODUCTIONApplications of surfactants in fields like lubrication or oil-wetting cleaners and detergency require the use of surfactant in either a water-free or water-poor medium. This has stimulated a significant amount of interest towards the micellization of various surfactants in non-aqueous, polar organic media [1,2] and in mixed solvent having a significant amount of a polar solvent mixed with water. [3][4][5][6][7][8][9][10][11][12] Glycols are well known for their use as coolants and antifreezes and find application in pharmaceutical, cosmetics, and food industries. [13] In most these applications, surfactant is also present and, therefore, it is important to study the effect of glycol on micellization of surfactants. The properties of surfactant micelles can change significantly as the polar glycol solvent replaces the water in the system. Also, the addition of glycols to aqueous micellar surfactant solutions provides an opportunity to study the so called solvophobic effect (as opposed to the hydrophobic effect), which is used to describe micellization in polar solvent [3,14] The micellization in these solvents is similar in many aspects to the micellization in water although micellization is not as favorable as in water for given surfactant. [15] There is enormous literature that deals with effect of aqueous ethylene glycol (EG) on micellization of cationic, anionic and nonionic surfactants. [3][4][5][6][7][8][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] From thermodynamic studies of micellization in presence of EG Ruiz [5,6] observed that due to lower cohesive energy of EG þwater mixed solvent system, aggregation number of micelles decreased. For alkyltrimethylammonium bromide surfactant in presence of aqueous EG and glycerol from electrochemical studies using surfactant selective electrode, Palepu and coworkers [3] concluded that logarithm of the critical micellar concentration (CMC) of surfactant is directly proportional to the solvent=water ratio expressed in weight percent. They have also investigate the effect of EG on binary mixtures of alkyltriphenylphosphonium brom...

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Ultrasonic behaviour of aqueous solutions of polyethylene glycols on the temperature of adiabatic compressibility minimum of water

Cited by 12 publications

References 10 publications

Hydrophobic hydration of cationic mixed micelles by alkoxyethanols in aqueous media

Hydrophobic hydration of cationic mixed micelles by alkoxyethanols in aqueous media

Crystallization and Crystallinity of Fluticasone Propionate

Thermodynamic Study of a Cationic Surfactant in Aqueous Solution Containing Ethylene Glycol and Its Oligomers: Effect of Number of Ethereal Oxygen Atoms in Glycols Molecule

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