1
|
Egamberdiev K, Mirzaev SZ, Kaatze U. The Effect of Alkali Halides on the Critical Exponents of the 2,6-Dimethylpyridine-Water System. J Phys Chem B 2016; 120:12379-12389. [PMID: 27934229 DOI: 10.1021/acs.jpcb.6b10329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The diffusion coefficients and shear viscosities of 2,6-dimethylpyridine-water mixtures of critical composition have been measured without and with small amounts of alkali halides added. The data have been analyzed in terms of power law behavior. Deviations from power law behavior indicate a coupling between the critical fluctuations in the local concentrations and the formation of mesoscopic molecular aggregates. The critical exponent of the fluctuation correlation length, the shear viscosity exponent, and the critical exponent of the relaxation rate of fluctuations have been evaluated to show noticeable influences from the salts. The correlation length exponent indicates a suppression of the critical fluctuations, whereas the viscosity exponent rather points at the activation of some extra fluctuations. No clear evidence has been obtained that the added salts affect the critical behavior, and thus cause the opposed effects in the exponents, directly by the long-range ionic fields. Alternatively, the ions may have an influence on the aggregate formation which in turn could modify the critical fluctuations either by reducing the region of true critical exponents or by affecting the critical behavior due to the presence as well as the formation and disintegration kinetics of the multimolecular structures.
Collapse
Affiliation(s)
- Kamoladdin Egamberdiev
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.,Department of Engineering Physics, Tashkent State Technical University , Do'rmon Yuli 33, 100125 Tashkent, Uzbekistan
| | - Sirojiddin Z Mirzaev
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.,Department of Engineering Physics, Tashkent State Technical University , Do'rmon Yuli 33, 100125 Tashkent, Uzbekistan
| | - Udo Kaatze
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| |
Collapse
|
2
|
Heinzelmann G, Seide P, Figueiredo W. Dynamics of micelle formation from temperature-jump Monte Carlo simulations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:052305. [PMID: 26651693 DOI: 10.1103/physreve.92.052305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Indexed: 06/05/2023]
Abstract
In the present work we perform temperature jumps in a surfactant solution by means of Monte Carlo simulations, investigating the dynamics of micelle formation. We use a lattice model that allows orientational freedom and hydrogen bonding for solvent molecules, which can make a connection between the different time scales of hydrogen bond formation and amphiphilic aggregation. When we perform a large jump between a high-temperature nonmicellized state and a micellized state, there is strong hysteresis between the heating and cooling processes, the latter showing the formation of premicelles that act as nucleation centers for the assembly of larger aggregates and the former is a drive for dissociation of the existing aggregates. Hysteresis is not seen when we perform a small jump between two states that can be both micellized or nonmicellized. Looking for a more detailed analysis of the hydrophobic effect that drives aggregation, we compare the time evolution of the solvent hydrogen bonds in our system close and far from micelles and how that is affected by the formation of large clusters at low temperatures. We find a strong connection between them, with the total number of hydrogen bonds in the system always increasing when micelles are formed. To gain insights into the mechanism of premicellar formation and growth, we measure the lifetime of micellized amphiphiles as a function of the aggregate size and the stage of the aggregation process. Our results indicate that the premicelles are always unstable, quickly exchanging amphiphiles with the solution due to their low probabilty in equilibrium. Furthermore, we find that the stability of individual surfactants in micelles increases with the aggregate size, with the lifetime of amphiphiles in large micelles being as much as 35 times longer than in the case of the unstable premicellar region.
Collapse
Affiliation(s)
- G Heinzelmann
- Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil
| | - P Seide
- Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil
| | - W Figueiredo
- Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil
| |
Collapse
|
3
|
Truszkowska D, Dzida M, Kaatze U. Effect of ionic additives on critical exponents of 2,6-dimethylpyridine–water. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.04.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
4
|
Heinzelmann G, Figueiredo W, Girardi M. Micellar dynamics and water–water hydrogen-bonding from temperature-jump Monte Carlo simulations. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
5
|
Schrader W, Behrends R, Kaatze U. Cholesterol-Induced Variations in the Domain Structure Fluctuations and Microdynamics of Lipid Membranes. J Phys Chem B 2012; 116:2446-54. [DOI: 10.1021/jp2106007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- W. Schrader
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen,
Germany
| | - R. Behrends
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen,
Germany
| | - U. Kaatze
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen,
Germany
| |
Collapse
|
6
|
Halstenberg S, Schrader W, Das P, Bhattacharjee JK, Kaatze U. Critical fluctuations in the domain structure of lipid membranes. J Chem Phys 2003. [DOI: 10.1063/1.1555634] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
7
|
Schrader W, Kaatze U. Zwitterion Headgroup Orientation Correlation and Mobility and the Domain Structure of Membranes. J Phys Chem B 2001. [DOI: 10.1021/jp010525t] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- W. Schrader
- Drittes Physikalisches Institut, Georg-August-Universität, Bürgerstrasse 42-44, 37073 Göttingen, Germany
| | - U. Kaatze
- Drittes Physikalisches Institut, Georg-August-Universität, Bürgerstrasse 42-44, 37073 Göttingen, Germany
| |
Collapse
|
8
|
Kaatze U, Mirzaev SZ. Slowing Down in Chemical Reactions. The Isobutyric Acid/Water System in the Critical Region. J Phys Chem A 2000. [DOI: 10.1021/jp0000984] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- U. Kaatze
- Drittes Physikalisches Institut, Georg-August Universität, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| | - S. Z. Mirzaev
- Heat Physics Department, Uzbek Academy of Sciences, Katartal Str. 28, 700135 Tashkent, Uzbekistan
| |
Collapse
|
9
|
Affiliation(s)
- L. De Maeyer
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany, and Drittes Physikalisches Institut, Universität Göttingen, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| | - C. Trachimow
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany, and Drittes Physikalisches Institut, Universität Göttingen, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| | - U. Kaatze
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany, and Drittes Physikalisches Institut, Universität Göttingen, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| |
Collapse
|
10
|
De Maeyer L, Trachimow C, Kaatze U. Simulation Study to Model Extremely Slow Reaggregation Processes in Micelle Solutions. J Phys Chem B 1998. [DOI: 10.1021/jp982215p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- L. De Maeyer
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany, and Drittes Physikalisches Institut, Georg-August-Universität, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| | - C. Trachimow
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany, and Drittes Physikalisches Institut, Georg-August-Universität, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| | - U. Kaatze
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany, and Drittes Physikalisches Institut, Georg-August-Universität, Bürgerstrasse 42-44, D-37073 Göttingen, Germany
| |
Collapse
|