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  • 1
    Electronic Resource
    Electronic Resource
    Large supramolecular structures in water-alcohol mixtures evidenced by elastic light scattering (1992)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 14 (1992), S. 333-341 
    Details
    ISSN: 0392-6737
    Keywords: Extinction, absorption, scattering, and transmission coefficients ; emissivity ; Structure of associated liquids ; Macromolecular and polymer solutions (solubility, swelling, etc.) ; polymer melts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report the results of different light scattering experiments, both elastic and quasi-elastic, performed as a function of temperature at different concentrations on a water-butoxyethanol (C4E1) mixture. The comparison of the obtained data with the results of SANS gives evidence of the amphiphilic character of the alcohol molecules. In particular, we observe such a property gives rise to a well-defined micellarlike structure. At low temperatures (T≤5°C) we find that the mixture exhibits a surprising behaviour, namely very large structures (of the order of 2000 Å) built by an intermicellar aggregation process. In addition when the light scattering data show the presence of such large aggregates, neutron data reveal the persisting presence of micelles of about 20 Å. Such a structural picture agrees with the behaviour of the viscosity data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457392
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  • 2
    Electronic Resource
    Electronic Resource
    Sound propagation in water–ethanol mixtures at low temperatures. II. Dynamical properties (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 7687-7697 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements of the ultrasonic absorption coefficient over the entire concentration range of ethanol aqueous solutions in the frequency range 10–250 MHz and for a temperature interval extending from +30 to −40 °C are presented. Large peaks, which increase noticeably as temperature and frequency decrease, are observed in the attenuation vs composition plot. A detailed analysis of these results and of the velocity dispersion data shows that the frequency spectra are better accounted for by the concentration fluctuations theory of Romanov and Solov'ev (RS) which assumes a distribution of relaxation times rather than by the quasichemical theories which consider single or double relaxation processes. We also show that the absorption and velocity expressions as given by RS can be put in such a form to allow the experimental data as a function of concentration, temperature, and frequency to be displayed on two single "universal'' plots. An analysis of the extracted RS theory parameters indicates that the large attenuations are mainly related to the small mutual diffusion coefficients of the solutions. At a molecular level the observed dynamical behavior is associated to the forming and breaking up of alcohol–water aggregates whose lifetimes at the peak concentration range from about 10−9 to 10−7 s on going from higher to lower temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454282
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  • 3
    Electronic Resource
    Electronic Resource
    Anomalous ultrasonic absorption in alkoxyethanols aqueous solutions near their critical and melting points (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 2587-2593 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ultrasonic absorption and velocity measurements have been performed in aqueous solutions of ethoxyethanol and n-butoxyethanol in the frequency range of 5–250 MHz and from about 50 °C to the respective melting temperatures (TM). The latter system exhibits a closed loop of miscibility with a LCST at TC=49 °C. The overall behavior of the absorption looks, in general, similar to previously investigated alcohol–water systems and critical binary mixtures. However, it shows two main characteristic features: (a) a noticeable increase of amplitude and dispersion of the peak values as the temperature decreases toward TM; (b) a weak critical anomaly which is seen only at the lowest frequencies and in a narrow temperature interval around TC. A comparison with the frequency and temperature predictions by the Romanov–Solov'ev fluctuation model and by the Ferrell–Bhattacharjee dynamic scaling theory for critical mixtures shows that the observed spectra near TM cannot be explained by critical-like phenomena. The occurrence of pseudocritical fluctuations, which extends their influence from TM to higher temperatures up TC, is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457019
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  • 4
    Electronic Resource
    Electronic Resource
    Brillouin light scattering in low temperature water–ethanol solutions (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 4469-4477 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Brillouin light scattering spectra of water–ethanol mixtures in a wide temperature and concentration range are reported and analyzed on the basis of a generalized hydrodynamic theory. The obtained sound velocities and longitudinal kinematic viscosity coefficients are compared with the analogous results obtained from ultrasonic measurements. In particular, light scattering spectra of 23% molar water–ethanol solution show direct evidence of a relaxation process in the GHz region which appears to be well separated from the lower frequency relaxation process determining the anomalous ultrasonic properties of these solutions. This high frequency relaxation involves both shear and volume viscosities and closely resembles the viscoelastic relaxation found in many associated liquids. The role played by the microscopic variables driving the relaxation is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454786
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  • 5
    Electronic Resource
    Electronic Resource
    Sound propagation in water–ethanol mixtures at low temperatures. I. Ultrasonic velocity (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 405-415 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ultrasonic velocity measurements in ethanol aqueous solutions from +30 to −40 °C over the entire composition range and in the frequency range 10–70 MHz are presented. The results, in combination with previous determinations up to +80 °C, allow us to follow the peculiar behavior of the adiabatic compressibility of this system in a very large temperature range extending from a region where the anomalies of pure water tend to disappear, down to the supercooled region where these anomalies are noticeably enhanced. A "normal'' and an "anomalous'' contribution to the isothermal compressibility of water, as derived from these data, is compared with previous evaluations and discussed in the framework of the existing theoretical models. The compressibility of the diluted solutions is interpreted in terms of stabilization of water into ordered, less dense, and more rigid structures around the solute. We show that a simple two-state model based on this concept and on the hypothesis of a structural breakdown at the concentration of maximum sound absorption can explain the main experimental features of the volumetric properties of these solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454616
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  • 6
    Electronic Resource
    Electronic Resource
    Dynamic shear viscosity measurements in aqueous sodium deoxycholate solutions
    Amsterdam : Elsevier
    Advances in Molecular Relaxation and Interaction Processes 24 (1982), S. 181-189 
    Details
    ISSN: 0378-4487
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0378-4487(82)80044-7
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  • 7
    Electronic Resource
    Electronic Resource
    Ultrasonic propagation in highly concentrated bile salts aqueous solutions
    Amsterdam : Elsevier
    Inorganica Chimica Acta 40 (1980), S. X112-X113 
    Details
    ISSN: 0020-1693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0020-1693(00)92210-2
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  • 8
    Electronic Resource
    Electronic Resource
    Sound dispersion in the critical mixture nitrobenzene-n-hexane
    Amsterdam : Elsevier
    Physics Letters A 35 (1971), S. 131-132 
    Details
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0375-9601(71)90584-6
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  • 9
    Electronic Resource
    Electronic Resource
    A small-angle neutron scattering study of 2-butoxyethanol/D2O solutions (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 2732-2737 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Small-angle neutron scattering (SANS) measurements have been performed in heavy water solutions of 2-butoxyethanol as a function of concentration and temperature. The results indicate that there exist some alcohol aggregation above a narrow concentration range (x=0.015–0.02, where x is the alcohol molar fraction) and the size of the aggregates increases with temperature taking a maximum value at a composition close to the critical concentration. The analysis of the size and of the absolute scattered intensity at q=0(I0) in terms of a microscopic model of aggregation, as well as the indications from other experiments, suggest that these aggregates are micelle-like structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460925
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  • 10
    Electronic Resource
    Electronic Resource
    Viscoelastic behavior of water/AOT/n-heptane microemulsions by ultrasonic absorption investigation (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 1304-1309 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ultrasonic absorption in water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-heptane system has been measured at 25 °C, as a function of the water/AOT molar ratio (X) and of the volume fraction (φ) of the micellar phase. The ultrasonic spectra have been found strongly dependent on φ and nearly independent on X. In particular, as φ increases, ultrasonic dynamics shifts from a single to a distribution of relaxation times with occurrence of viscoelastic effects. Such findings have been correlated to the increased connectivity of the micellar network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461112
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