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Szewczyk J, Babacic V, Krysztofik A, Ivashchenko O, Pochylski M, Pietrzak R, Gapiński J, Graczykowski B, Bechelany M, Coy E. Control of Intermolecular Interactions toward the Production of Free-Standing Interfacial Polydopamine Films. ACS Appl Mater Interfaces 2023. [PMID: 37489635 PMCID: PMC10401576 DOI: 10.1021/acsami.3c05236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Aggregation of the polydopamine (PDA) molecular building blocks at the air/water interface leads to obtaining large surface nanometric-thin films. This mechanism follows two possible pathways, namely, covalent or non-covalent self-assembly, which result in a different degree of structure order and, consequently, different structural properties. Control of this mechanism could be vital for applications that require true self-support PDA free-standing films, for example, electrochemical sensing or membrane technology. Here, we are considering the impact of boric acid (BA) and Cu2+ ions on the mentioned mechanism exclusively for the free-standing films from the air/water interface. We have employed and refined our own spectroscopic reflectometry method to achieve an exceptionally high real-time control over the thickness growth. It turned out that BA and Cu2+ ions significantly impact the film growth process. Reduction of the nanoparticles size and their number was examined via UV-vis spectroscopy and transmission electron microscopy, showing a colossal reduction in the mean diameter of nanoparticles in the case of BA and a moderate reduction in the case of Cu2+. This modification is leading to significant enhancement of the process efficiency through moderation of the topological properties of the films, as revealed by atomic force microscopy. Next, applying infrared, Raman, and X-ray photoelectron spectroscopy, we presented small amounts of metal (B or Cu) in the final structure of PDA and simultaneously their vital role in the oxidation mechanism and cross-linking through covalent or non-covalent bonds. Therefore, we revealed the possibility of synthesizing films via the expected self-assembly mechanism which has hitherto been out of control. Moreover, modification of mechanical properties toward exceptionally elastic films through the BA-assisted synthesis pathway was shown by achieving Young's modulus value up to 24.1 ± 5.6 and 18.3 ± 6.4 GPa, using nanoindentation and Brillouin light scattering, respectively.
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Affiliation(s)
- Jakub Szewczyk
- NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614 Poznan, Poland
- Institut Européen des Membranes, IEM, UMR 5635, Univ Montpellier, CNRS, ENSCM Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Visnja Babacic
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Adam Krysztofik
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Olena Ivashchenko
- NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614 Poznan, Poland
| | - Mikołaj Pochylski
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Robert Pietrzak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Jacek Gapiński
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Bartłomiej Graczykowski
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Mikhael Bechelany
- Institut Européen des Membranes, IEM, UMR 5635, Univ Montpellier, CNRS, ENSCM Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
- Gulf University for Science and Technology, GUST, 32093 Hawally, Kuwait
| | - Emerson Coy
- NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614 Poznan, Poland
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Białek R, Vasileiadis T, Pochylski M, Graczykowski B. Fano meets Stokes: Four-order-of-magnitude enhancement of asymmetric Brillouin light scattering spectra. Photoacoustics 2023; 30:100478. [PMID: 37025113 PMCID: PMC10070932 DOI: 10.1016/j.pacs.2023.100478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Observation of Fano resonances in various physical phenomena is usually ascribed to the coupling of discrete states with background continuum, as it has already been reported for various physical phenomena. Here, we report on Fano lineshapes of nonthermal GHz phonons generated and observed with pumped Brillouin light scattering in gold-silicon thin membranes, overlapping the broad zero-shift background of yet questionable origin. The system's broken mid-plane symmetry enabled the generation of coherent quasi-symmetric and quasi-antisymmetric Lamb acoustic waves/phonons, leading to the four orders-of-magnitude enhancement of Brillouin light scattering. Notably, the membrane asymmetry resulted also in the mode-dependent Stokes and anti-Stokes Fano lineshapes asymmetry.
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Affiliation(s)
- Rafał Białek
- Faculty of Physics, Adam Mickiewicz University, Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Thomas Vasileiadis
- Faculty of Physics, Adam Mickiewicz University, Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Mikołaj Pochylski
- Faculty of Physics, Adam Mickiewicz University, Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Bartłomiej Graczykowski
- Faculty of Physics, Adam Mickiewicz University, Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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Ciężar K, Pochylski M. 2A novel method of the analysis and classification of meibomian gland images. Cont Lens Anterior Eye 2022. [DOI: 10.1016/j.clae.2022.101601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Połatyńska A, Tomczyk K, Pochylski M, Meier G, Gapinski J, Banachowicz E, Śliwa T, Patkowski A. Temperature dependent FCS studies using a long working distance objective: Viscosities of supercooled liquids and particle size. J Chem Phys 2018; 146:084506. [PMID: 28249427 DOI: 10.1063/1.4977047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, we describe new experimental setups for Fluorescence Correlation Spectroscopy (FCS) where a long working distance objective is used. Using these setups, FCS measurements in a broad temperature range for a small sample volume of about 50 μl can be performed. The use of specially designed cells and a dry long working distance objective was essential for avoiding temperature gradients in the sample. The performance of the new setups and a traditional FCS setup with immersion objectives is compared. The FCS data in combination with the Stokes-Einstein (SE) relation were used to obtain the values of the nanoviscosity of a fluid. We show for selected molecular van der Waals supercooled liquids that despite the fact that in these systems, a characteristic length scale can be defined, the nanoviscosity obtained from FCS is in a very good agreement with the macroscopic (rheometric) viscosity of the sample in a broad temperature range. This result corroborates the applicability of the SE relation to supercooled liquids at temperatures above 1.2 Tg. We also show that the temperature dependent size of thermoresponsive microgel particles can be determined by FCS using the designed cells and a long working distance objective in a broader size range without a need to use the correction procedure since the size correction is proportional to the square of the ratio of the hydrodynamic radius to the confocal volume size.
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Affiliation(s)
- Agnieszka Połatyńska
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Karolina Tomczyk
- Institute of Complex Systems, Soft Condensed Matter, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Mikołaj Pochylski
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Gerd Meier
- Institute of Complex Systems, Soft Condensed Matter, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Jacek Gapinski
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Ewa Banachowicz
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Tomasz Śliwa
- Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, 60965 Poznan, Poland
| | - Adam Patkowski
- Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
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Koralewski M, Balejčíková L, Mitróová Z, Pochylski M, Baranowski M, Kopčanský P. Morphology and Magnetic Structure of the Ferritin Core during Iron Loading and Release by Magnetooptical and NMR Methods. ACS Appl Mater Interfaces 2018; 10:7777-7787. [PMID: 29417811 DOI: 10.1021/acsami.7b18304] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ferritins are proteins, which serve as a storage and transportation capsule for iron inside living organisms. Continuously charging the proteins with iron and releasing it from the ferritin is necessary to assure proper management of these important ions within the organism. On the other hand, synthetic ferritins have great potential for biomedical and technological applications. In this work, the behavior of ferritin during the processes of iron loading and release was examined using multiplicity of the experimental technique. The quality of the protein's shell was monitored using circular dichroism, whereas the average size and its distribution were estimated from dynamic light scattering and transmission electron microscopy images, respectively. Because of the magnetic behavior of the iron mineral, a number of magnetooptical methods were used to gain information on the iron core of the ferritin. Faraday rotation and magnetic linear birefringence studies provide evidence that the iron loading and the iron-release processes are not symmetrical. The spatial organization of the mineral within the protein's core changes depending on whether the iron was incorporated into or removed from the ferritin's shell. Magnetic optical rotatory dispersion spectra exclude the contribution of the Fe(II)-composed mineral, whereas joined magnetooptical and nuclear magnetic resonance results indicate that no mineral with high magnetization appear at any stage of the loading/release process. These findings suggest that the iron core of loaded/released ferritin consists of single-phase, that is, ferrihydrite. The presented results demonstrate the usefulness of emerging magnetooptical methods in biomedical research and applications.
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Affiliation(s)
- Marceli Koralewski
- Faculty of Physics , Adam Mickiewicz University , Umultowska 85 , 61-614 Poznań , Poland
| | - Lucia Balejčíková
- Institute of Experimental Physics , SAS , Watsonova 47 , 040 01 Kosice , Slovakia
- Institute of Measurement Science , SAS , Dubravska cesta 9 , 841 04 Bratislava 4 , Slovakia
| | - Zuzana Mitróová
- Institute of Experimental Physics , SAS , Watsonova 47 , 040 01 Kosice , Slovakia
| | - Mikołaj Pochylski
- Faculty of Physics , Adam Mickiewicz University , Umultowska 85 , 61-614 Poznań , Poland
| | - Mikołaj Baranowski
- Faculty of Physics , Adam Mickiewicz University , Umultowska 85 , 61-614 Poznań , Poland
| | - Peter Kopčanský
- Institute of Experimental Physics , SAS , Watsonova 47 , 040 01 Kosice , Slovakia
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6
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Wojnarowska Z, Rams-Baron M, Knapik-Kowalczuk J, Połatyńska A, Pochylski M, Gapinski J, Patkowski A, Wlodarczyk P, Paluch M. Experimental evidence of high pressure decoupling between charge transport and structural dynamics in a protic ionic glass-former. Sci Rep 2017; 7:7084. [PMID: 28765639 PMCID: PMC5539233 DOI: 10.1038/s41598-017-07136-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 06/23/2017] [Indexed: 11/16/2022] Open
Abstract
In this paper the relaxation dynamics of ionic glass-former acebutolol hydrochloride (ACB-HCl) is studied as a function of temperature and pressure by using dynamic light scattering and broadband dielectric spectroscopy. These unique experimental data provide the first direct evidence that the decoupling between the charge transport and structural relaxation exists in proton conductors over a wide T-P thermodynamic space, with the time scale of structural relaxation being constant at the liquid-glass transition (τα = 1000 s). We demonstrate that the enhanced proton transport, being a combination of intermolecular H+ hopping between cation and anion as well as tautomerization process within amide moiety of ACB molecule, results in a breakdown of the Stokes-Einstein relation at ambient and elevated pressure with the fractional exponent k being pressure dependent. The dTg/dP coefficient, stretching exponent βKWW and dynamic modulus Ea/ΔV# were found to be the same regardless of the relaxation processes studied. This is in contrast to the apparent activation volume parameter that is different when charge transport and structural dynamics are considered. These experimental results together with theoretical considerations create new ideas to design efficient proton conductors for potential electrochemical applications.
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Affiliation(s)
- Z Wojnarowska
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007, Katowice, Poland. .,Silesian Center for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500, Chorzow, Poland.
| | - M Rams-Baron
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007, Katowice, Poland.,Silesian Center for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500, Chorzow, Poland
| | - J Knapik-Kowalczuk
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007, Katowice, Poland.,Silesian Center for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500, Chorzow, Poland
| | - A Połatyńska
- Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland
| | - M Pochylski
- Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland
| | - J Gapinski
- Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland.,NanoBioMedical Centre, A. Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland
| | - A Patkowski
- Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland.,NanoBioMedical Centre, A. Mickiewicz University, Umultowska 85, 61-614, Poznan, Poland
| | - P Wlodarczyk
- Institute of Non-Ferrous Metals, Sowinskiego 5, 44-100, Gliwice, Poland
| | - M Paluch
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007, Katowice, Poland.,Silesian Center for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500, Chorzow, Poland
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7
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Koralewski M, Pochylski M, Gierszewski J. Magnetic properties of ferritin and akaganeite nanoparticles in aqueous suspension. J Nanopart Res 2013; 15:1902. [PMID: 24532980 PMCID: PMC3920033 DOI: 10.1007/s11051-013-1902-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 07/26/2013] [Indexed: 05/25/2023]
Abstract
We have studied the magnetically induced optical birefringence Δn of horse spleen ferritin (HSF) and aqueous suspensions of several different-sized iron oxyhydroxide nanoparticles coated with different polysaccharides mimicking ferritin. The structure and dimensions of the akaganeite mineral core were characterized by XRD and TEM, respectively. The stability of the suspensions in the measurement temperature range from 278 to 358 K was confirmed by UV-Vis absorption spectroscopy. The values of optical polarizability anisotropy Δα, magnetic susceptibility anisotropy Δχ, and permanent magnetic dipole moment μm of the akaganeite nanoparticles have been estimated on the basis of the temperature dependence of the Cotton-Mouton (C-M) constant. The magnetic birefringence of Fe-sucrose has been described tentatively by different types of Langevin function allowing another estimation of Δχ and μm. The obtained permanent magnetic dipole moment μm of the studied akaganeite nanoparticles proves small and comparable to that of HSF. The value of μm is found to increase with decreasing nanoparticle diameter. Observed in a range spanning more than five orders of magnitude, the linear relation between the C-M constant and the iron concentration provides a basis for possible analytical application of the C-M effect in biomedicine. The established relation between the C-M constant and the nanoparticle diameter confirms that the dominant contribution to the measured magnetic birefringence comes from the magnetic susceptibility anisotropy Δχ. A comparison of the C-M constants of the studied akaganeite nanoparticles with the data obtained for HSF provides evidence that the ferritin core behaves as a non-Euclidian solid.
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Affiliation(s)
- Marceli Koralewski
- Optics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - Mikołaj Pochylski
- Optics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - Jacek Gierszewski
- Optics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
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Aliotta F, Calandra P, Pochylski M, Ponterio RC, Salvato G, Vasi C. Enhancement of electrorheological effect by particle-fluid interaction. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 87:062304. [PMID: 23848672 DOI: 10.1103/physreve.87.062304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Indexed: 06/02/2023]
Abstract
The influence of interactions between particle surface and host fluids in electrorheological suspensions is explored. It is observed that dispersions of nanosized particles of titania in octanoid acid exhibit an anomalously large electrorheologic effect when compared with a similar dispersion of micrometric particles or with a more conventional colloidal suspension of silica in silicone oil. The effect is interpreted as originated by the formation of a thin layer of octanoid acid molecules with the surface of the titania solid particle. The experimental data are fitted with the outcomes of a modified version of conductive models existing in the literature. It is suggested that anomalous large electrorheological effect is mainly originated by the increasing of the effective radius of the nanometric particles, which results in an increasing of the effective volume fraction of the dispersed phase. It is also shown that the deformation of the soft shell around the solid particles, induced by Coulombic force, plays a not negligible role. Some hints for tailoring electrorheologic fluids suitable for different applications are proposed.
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Affiliation(s)
- F Aliotta
- CNR-Istituto per i Processi Chimico-Fisici, Viale Ferdinando Stagno d'Alcontres 37, I-98158 Messina, Italy.
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Aliotta F, Gapiński J, Pochylski M, Ponterio RC, Saija F, Salvato G, Vasi C. High-frequency propagating density fluctuations in deeply supercooled water: evidence of a single viscous relaxation. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 87:022303. [PMID: 23496512 DOI: 10.1103/physreve.87.022303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Indexed: 05/21/2023]
Abstract
We performed a Brillouin scattering experiment on deeply supercooled water and compared the results with similar literature data obtained both at the same and at higher values of the exchanged wave vector. The whole set of available experimental data can be well reproduced with the use of the generalized hydrodynamic model where all the involved thermodynamic parameters are fixed to their literature values. On the contrary, the model based on the memory function approach generates the wrong estimates for measurables when the same values of the thermodynamic parameters are used. This result confirms our recent criticisms against the utilization of models originating from linear response theory [Phys. Rev. E 84, 051202 (2011)]. The inconsistency between models explains apparent discrepancies between the different conclusions on water acoustic behavior which may be found in the literature. We demonstrate that the observed behavior can be explained by assuming only a single relaxation process that is typical of any viscoelastic system. With all thermodynamics quantities fixed, the hydrodynamic description needs only two parameters to model the experimental data, namely, the relaxation time and the high-frequency limit of the sound velocity. The whole body of the experimental data can be well reproduced when the relaxation time behaves in an Arrhenian manner and the difference between the relaxed and not relaxed sound velocities is a constant. The high-frequency sound velocity is never higher than 2200 m/s. We conclude that, at least from experiments performed within the hydrodynamic regime, there is no indication for a fast sound close to the hypersonic velocity observed in ice.
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Affiliation(s)
- F Aliotta
- CNR-IPCF, Laboratorio di Tecniche Spettroscopiche, Viale F. Stagno d'Alcontres 37, Messina IT-98158, Italy
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10
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Aliotta F, Gapiński J, Pochylski M, Ponterio RC, Saija F, Vasi C. Collective acoustic modes in liquids: a comparison between the generalized-hydrodynamics and memory-function approaches. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 84:051202. [PMID: 22181402 DOI: 10.1103/physreve.84.051202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 09/14/2011] [Indexed: 05/21/2023]
Abstract
The most familiar approaches used to describe the dynamical structure factor from adiabatic density fluctuations in liquids are based on generalized hydrodynamics and on the memory function, respectively. We show that, contrary to the common belief, the two approaches are not fully equivalent. In particular, models based on the memory function of a normalized damped oscillator fail in reproducing the correct experimental spectral profiles of systems close to the relaxation process. The discrepancy is due to misleading interpretation of the theoretical memory-function expressions, producing an unavoidable mixing of spectral contribution at different wave vectors when the theory is forced beyond its limits of validity.
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Affiliation(s)
- F Aliotta
- CNR-IPCF, Laboratorio di Tecniche Spettroscopiche, Messina, Italy.
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Aliotta F, Ponterio R, Saija F, Gapiński J, Pochylski M. Relaxation dynamics and evidence of scaling behaviours in aqueous polymer solutions. J Mol Liq 2011. [DOI: 10.1016/j.molliq.2010.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Saija F, Aliotta F, Fontanella ME, Pochylski M, Salvato G, Vasi C, Ponterio RC. Communication: An extended model of liquid bridging. J Chem Phys 2010; 133:081104. [DOI: 10.1063/1.3483690] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
| | - Jacek Gapiński
- Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
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14
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Pochylski M, Aliotta F, Ponterio RC, Saija F, Gapiński J. Some Evidence of Scaling Behavior in the Relaxation Dynamics of Aqueous Polymer Solutions. J Phys Chem B 2010; 114:1614-20. [DOI: 10.1021/jp9052456] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Pochylski
- Department of Physics, Adam Mickiewicz University, Poznań, Poland, and Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy
| | - F. Aliotta
- Department of Physics, Adam Mickiewicz University, Poznań, Poland, and Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy
| | - R. C. Ponterio
- Department of Physics, Adam Mickiewicz University, Poznań, Poland, and Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy
| | - F. Saija
- Department of Physics, Adam Mickiewicz University, Poznań, Poland, and Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy
| | - J. Gapiński
- Department of Physics, Adam Mickiewicz University, Poznań, Poland, and Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy
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Abstract
Brillouin scattering experiments have been carried out on some mixtures of molecular liquids. From the measurement of the hypersonic velocities we have evaluated the adiabatic compressibility as a function of the volume fraction. We show how the quadratic form of the excess compressibility dependence on the solute volume fraction can be derived by simple statistical effects and does not imply any interaction among the components of the system other than excluded volume effects. This idea is supported by the comparison of the experimental results with a well-established prototype model, consisting of a binary mixture of hard spheres with a nonadditive interaction potential. This naive model turns out to be able to produce a very wide spectrum of structural and thermodynamic features depending on values of its parameters. An attempt has made to understand what kind of structural information can be gained through the analysis of the volume fraction dependence of the compressibility.
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Affiliation(s)
- F Aliotta
- Istituto per i Processi Chimico-Fisici del CNR, Sede di Messina, Via La Farina 237, 98123 Messina, Italy
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16
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Pochylski M, Aliotta F, Blaszczak Z, Gapiński J. Structuring Effects and Hydration Phenomena in Poly(Ethylene Glycol)/Water Mixtures Investigated by Brillouin Scattering. J Phys Chem B 2006; 110:20533-9. [PMID: 17034240 DOI: 10.1021/jp0620973] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aqueous solutions of poly(ethylene glycol) (PEG) of mean molecular mass of 600 g/mol (PEG600) are investigated by Brillouin scattering technique. At high PEG content, a relaxation phenomenon is observed, which is related to a local rearrangement of the polymer structure where the interaction, via hydrogen bonding, with the solvent molecules plays a role. The obtained values of the relaxation times match the literature data very well for a fast relaxation time revealed by dielectric relaxation measurements in very similar mixtures. The calculated concentration behaviors of the excess adiabatic compressibility turns out in good agreement with the previous findings from ultrasonic measurements at 3 MHz. The observed minimum in the adiabatic compressibility is interpreted as the result of the interaction between water and the EO units of the PEG chain, which results in a structure tighter then that typical of bulk water and of pure PEG600. Such a hypothesis is supported by the observation that volume fraction value of about 0.3 coincides with the concentration value at which full hydration of EO units takes place. The observation that at the same concentration, the polymer coils start to overlap each other further supports the idea that the adiabatic compressibility behavior is monitoring the structural evolution of the mixture. However, similar results are obtained for largely different binary mixture which suggests caution in taking this conclusion too literally. In particular, the hypothesis that the occurrence of an extreme in the excess adiabatic compressibility could be simply originated by statistical effects and that further work is required for disentangling entropic contribution from effects of hetero-association and self-aggregation of one or both the components.
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Affiliation(s)
- M Pochylski
- Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy Department of Physics, Adam Mickiewicz University, Poland.
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Pochylski M, Aliotta F, Błaszczak Z, Gapiński J. Evidences of Nonideal Mixing in Poly(ethylene Glycol)/Organic Solvent Mixtures by Brillouin Scattering. J Phys Chem B 2005; 110:485-93. [PMID: 16471559 DOI: 10.1021/jp053813o] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The concentration dependence of the hypersonic properties of solutions of poly(ethylene glycol) of mean molecular mass 600 g/mol (PEG600) in benzene and toluene has been investigated by Brillouin scattering. The two solvents are very similar in structure and chemical properties, but while benzene is nonpolar, toluene possess a modest dipole. In both solvents a high-frequency relaxation process has been observed at high concentrations which has been assigned to conformational rearrangements of the polymeric chains, triggered by reorientation of the side groups. In both cases, the concentration dependence of the adiabatic compressibility deviates significantly from linearity, indicating the existence of nonideal mixing phenomena driven by aggregation processes taking place in the systems. However, there is no temperature dependence for solutions of PEG600 in benzene; on the contrary, the results obtained for solutions of PEG600 in toluene are noticeably dependent on the temperature. The comparison of the experimental data with the results of previous experiments on similar systems allows a general picture for weakly interacting mixtures of hydrogen-bonded systems and organic solvents to be developed. In particular, in the presence of a nonpolar solvent molecule the local structure of the mixture is dominated by solute self-association processes and any resulting solute-solvent correlation is barely induced by excluded volume effects. At high enough dilution the self-aggregation of solute molecules produces a variety of new local topologies that cannot be observed in bulk solute, and as a consequence, the concentration evolution of the system is too rich to be described in terms of a linear combination of a few components over the whole concentration range. The situation seems to be simpler for the polar toluene solvent molecules, where a three-component model seems able to fit the experimental concentration dependence of the hypersonic velocity. This result is interpreted to imply that the interaction between the solvent dipoles and the active sites of the solute produces a relatively stable heterocoordination, while the relevance of self-association is partially reduced.
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Affiliation(s)
- M Pochylski
- Istituto per I Processi Chimico Fisici del CNR, sezione di Messina, Italy
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Błaszczak Z, Pochylski M, Iwaszkiewicz-Kostka I, Ziobrowski P, Drozdowski M, Farhoud M. Brillouin scattering study of polyethylene glycol different solutions. J Mol Liq 2005. [DOI: 10.1016/j.molliq.2004.10.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pochylski M, Aliotta F, Błaszczak Z, Gapiński J. Structural Relaxation Processes in Polyethylene Glycol/CCl4 Solutions by Brillouin Scattering. J Phys Chem B 2005; 109:4181-8. [PMID: 16851480 DOI: 10.1021/jp045130z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present results of a Brillouin scattering experiment on solutions of poly(ethylene glycol) of mean molecular mass 600 g/mol (PEG600) in CCl4. The relaxation process detected has been assigned to conformational rearrangements of the polymeric chains, triggered by reorientation of the side groups. The concentration dependencies of the hypersound velocity and normalized absorption are compared against the indications from several models proposed in the literature. The concentration evolution of the system is described in terms of two distinct regimes. At high polymer content, the system is dominated by the structure of the dense polymer, where polymer-polymer interactions, together with excluded volume effects, induce the existence of a preferred local arrangement resulting in a narrow distribution of the relaxation times, with the average value of the relaxation time following a simple Arrhenius temperature dependence. As the concentration decreases, the original structure of the hydrogen bonded polymer network is destroyed, and a number of different local configuration coexist, giving rise to a wider distribution of relaxation times or to a multiple relaxation. At low concentrations, the experimental data are well fitted assuming a Vogel-Fulker-Tammon behavior for the average relaxation time. In addition, the observed deviation from the ideal behavior for the refractive index and the density suggests that CCl4 does not behave as an inert solvent, and due to polarization effects, it can develop local hetero-associated structures via electrostatic interaction with the O-H end groups of the polymeric chains. The hypothesis has been successfully tested by fitting the concentration behavior of the hypersonic velocity to a recent three-component model, suitable to describe the concentration dependence of sound velocity in moderately interacting fluids. The indication of the model furnishes a very high value for the association constant of the PEG600, confirming the literature indication that, in polymeric systems capable of developing long liner aggregates via hydrogen bonding interaction, the Brillouin probe is insensitive to the true length of the polymeric chains. The Brillouin scattering experiment just sees an effective hydrogen bonded aggregate that is huge relative to the length of the single polymeric chain and becomes sensitive only to the density fluctuations of the local segmental motions.
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Affiliation(s)
- M Pochylski
- Division of Optics, Department of Physics, Adam Mickiewicz University, Poland.
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