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Giraudet C, Papavasileiou KD, Rausch MH, Chen J, Kalantar A, van der Laan GP, Economou IG, Fröba AP. Characterization of Water Solubility in n-Octacosane Using Raman Spectroscopy. J Phys Chem B 2017; 121:10665-10673. [PMID: 29091450 DOI: 10.1021/acs.jpcb.7b07580] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, we demonstrate the ability of polarization-difference Raman spectroscopy (PDRS) to detect dissolved free water molecules in a n-octacosane (n-C28H58) liquid-rich phase, and thus to determine its solubility, at temperatures and pressures relevant to the Fischer-Tropsch synthesis. Our results for the pure alkane reveal thermal decomposition above a temperature of 500 K as well as an increase of gauche conformers of the alkane chains with an increase in temperature. For binary homogeneous mixtures, raw spectra obtained from two different polarization scattering geometries did not show a relevant signal in the OH stretching frequency range. In contrast, isotropic spectra obtained from the PDRS technique reveal a narrow and tiny peak associated with the dangling OH bonds. Over the complete range of temperatures and pressures, no signature of hydrogen-bonded water molecules was observed in the isotropic Raman scattering intensities. A thorough investigation covering a large range of temperatures and pressures using PDRS signals showed that the higher the fraction of gauche conformers of hydrocarbon, the higher the solubility of water. The proportion of gauche and trans conformers was found to be water-concentration-independent, and the intensity of the OH-dangling peak increased linearly with increasing the vapor partial pressure of water. Therefore, we established a relation between a relevant intensity ratio and the concentration of water obtained from SAFT calculations. Contrary to the results from relevant literature, the calibration factor was found to be temperature-independent between 424 and 572 K. The isotropic Raman scattering intensities are corrected in order to provide a better representation of the vibrational density of states. The influence of correction of the isotropic scattering intensities on the solubility measurements as well as on the analysis of the molecular arrangement is discussed.
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Affiliation(s)
- Cédric Giraudet
- Institute of Advanced Optical Technologies-Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Paul-Gordan-Straße 6, 91052 Erlangen, Germany
| | - Konstantinos D Papavasileiou
- National Centre for Scientific Research "Demokritos" , Institute of Nanoscience and Nanotechnology, Molecular Thermodynamics and Modelling of Materials Laboratory, GR-15310 Aghia Paraskevi, Attikis, Greece
| | - Michael H Rausch
- Institute of Advanced Optical Technologies-Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Paul-Gordan-Straße 6, 91052 Erlangen, Germany
| | - Jiaqi Chen
- Shell Global Solutions International B.V. , Grasweg 31, 1031 HW Amsterdam, The Netherlands
| | - Ahmad Kalantar
- Shell Global Solutions International B.V. , Grasweg 31, 1031 HW Amsterdam, The Netherlands
| | - Gerard P van der Laan
- Shell Global Solutions International B.V. , Grasweg 31, 1031 HW Amsterdam, The Netherlands
| | - Ioannis G Economou
- National Centre for Scientific Research "Demokritos" , Institute of Nanoscience and Nanotechnology, Molecular Thermodynamics and Modelling of Materials Laboratory, GR-15310 Aghia Paraskevi, Attikis, Greece.,Chemical Engineering Program, Texas A&M University at Qatar , Education City, P.O. Box 23874, Doha, Qatar
| | - Andreas P Fröba
- Institute of Advanced Optical Technologies-Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Paul-Gordan-Straße 6, 91052 Erlangen, Germany
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Jamadagni SN, Godawat R, Garde S. How surface wettability affects the binding, folding, and dynamics of hydrophobic polymers at interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13092-13099. [PMID: 19492828 DOI: 10.1021/la9011839] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present an extensive molecular simulation study of the behavior of a flexible hydrophobic 25-mer polymer at interfaces presenting a range of chemistries from hydrophobic (-CH(3)) to hydrophilic (-CONH(2)). We quantify the free energy of adsorption, conformational equilibria, and translational and conformational dynamics of the polymer at these diverse interfaces. Water-mediated interactions drive the polymer to adsorb strongly at a hydrophobic interface and repel it from hydrophilic ones. At hydrophilic surfaces, van der Waals interactions between the polymer and the surface mitigate this water-mediated repulsion, leading to weak adsorption of the polymer. Although the polymer is strongly adsorbed to hydrophobic surfaces, it is also most dynamic there. Translational diffusion and conformational dynamics are faster at hydrophobic surfaces compared to those at hydrophilic ones. In bulk water, the polymer collapses into compact globular shapes, whereas the thermodynamic stability of folded polymers is significantly lowered at hydrophobic surfaces. The polymer spreads into pancake-like 2D conformations at hydrophobic surfaces and gradually beads up into globular shapes as the surface is made more hydrophilic. Interestingly, the binding thermodynamics and dynamics correlate with macroscopic droplet contact angles that characterize the wetting properties of the different interfaces.
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Affiliation(s)
- Sumanth N Jamadagni
- The Howard P. Isermann Department of Chemical & Biological Engineering and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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Affiliation(s)
- Charles D. Eads
- Miami Valley Laboratories, The Procter & Gamble Company, P.O. Box 538707, Cincinnati, Ohio 45253
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La Rosa M, Schiesser CH, Uhlherr A, Drummond CJ, Moody K, Bohun R. A simple model of the hydrophobic effect for molecular simulation of interfacial phenomena. MOLECULAR SIMULATION 2002. [DOI: 10.1080/0892702021000002494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Eads CD. Simple Lattice Model for Solvation of Nonpolar Molecules in Hydrogen-Bonded Liquids. J Phys Chem B 2000. [DOI: 10.1021/jp993472c] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Charles D. Eads
- Miami Valley Laboratories, The Procter & Gamble Company, P.O. Box 538707, Cincinnati, Ohio 45253-8707
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Gittings MR, Cipelletti L, Trappe V, Weitz DA, In M, Marques C. Structure of Guar in Solutions of H2O and D2O: An Ultra-Small-Angle Light-Scattering Study. J Phys Chem B 2000. [DOI: 10.1021/jp9943833] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. R. Gittings
- Complex Fluids/CNRS Laboratory, Rhodia Inc., CN 7500, Cranbury, New Jersey 08512-7500, and Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396
| | - Luca Cipelletti
- Complex Fluids/CNRS Laboratory, Rhodia Inc., CN 7500, Cranbury, New Jersey 08512-7500, and Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396
| | - V. Trappe
- Complex Fluids/CNRS Laboratory, Rhodia Inc., CN 7500, Cranbury, New Jersey 08512-7500, and Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396
| | - D. A. Weitz
- Complex Fluids/CNRS Laboratory, Rhodia Inc., CN 7500, Cranbury, New Jersey 08512-7500, and Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396
| | - M. In
- Complex Fluids/CNRS Laboratory, Rhodia Inc., CN 7500, Cranbury, New Jersey 08512-7500, and Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396
| | - C. Marques
- Complex Fluids/CNRS Laboratory, Rhodia Inc., CN 7500, Cranbury, New Jersey 08512-7500, and Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396
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Wu MG, Deem MW. Analytical rebridging Monte Carlo: Application to cis/trans isomerization in proline-containing, cyclic peptides. J Chem Phys 1999. [DOI: 10.1063/1.479952] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Suresh SJ, Naik VM. A multilayer theory for interfacial properties of systems containing hydrogen bonding molecules. J Chem Phys 1998. [DOI: 10.1063/1.477228] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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