Vincent Caqueret, K. Berkalou, Jean-Louis Havet, M. Debacq, S. Vitu
Vapor–liquid equilibrium (VLE) and density data for binary systems of branched alkanes + ethyl acetate are scarce in the literature. In this study, the binary mixtures 3-methylpentane + ethyl acetate and 2,3-dimethylbutane + ethyl acetate were investigated. Density measurements at atmospheric pressure were performed using a vibrating tube density meter at 293.15, 298.15 and 303.15 K. Large and positive excess molar volumes were calculated and correlated using a Redlich–Kister-type equation. Isobaric VLE data at 101.3 kPa were obtained using a Gillespie-type recirculation ebulliometer. Equilibrium compositions were determined indirectly from density measurements. The experimental data were checked for consistency by means of the Fredenslund test and the Wisniak (L-W) test and were then successfully correlated using the NRTL model. The newly studied binary systems display high deviations from ideality and minimum boiling azeotropes, the coordinates of which are reported in this work.
{"title":"Density, Excess Molar Volume and Vapor–Liquid Equilibrium Measurements at 101.3 kPa for Binary Mixtures Containing Ethyl Acetate and a Branched Alkane: Experimental Data and Modeling","authors":"Vincent Caqueret, K. Berkalou, Jean-Louis Havet, M. Debacq, S. Vitu","doi":"10.3390/liquids3020014","DOIUrl":"https://doi.org/10.3390/liquids3020014","url":null,"abstract":"Vapor–liquid equilibrium (VLE) and density data for binary systems of branched alkanes + ethyl acetate are scarce in the literature. In this study, the binary mixtures 3-methylpentane + ethyl acetate and 2,3-dimethylbutane + ethyl acetate were investigated. Density measurements at atmospheric pressure were performed using a vibrating tube density meter at 293.15, 298.15 and 303.15 K. Large and positive excess molar volumes were calculated and correlated using a Redlich–Kister-type equation. Isobaric VLE data at 101.3 kPa were obtained using a Gillespie-type recirculation ebulliometer. Equilibrium compositions were determined indirectly from density measurements. The experimental data were checked for consistency by means of the Fredenslund test and the Wisniak (L-W) test and were then successfully correlated using the NRTL model. The newly studied binary systems display high deviations from ideality and minimum boiling azeotropes, the coordinates of which are reported in this work.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"100 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77156332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interactions between DNA and graphene are paramount for a wide range of applications, such as biosensing and nanoelectronics; nonetheless, the molecular details of such interactions remain largely unexplored. We employ atomically detailed molecular dynamics simulations with an enhanced sampling technique to investigate the adsorption and mobility of double-stranded DNA along the basal plane of graphene, in an electrolytic aqueous medium. The study focuses on physiologically relevant conditions, using a buffer of [NaCl] = 134 mM. DNA physisorption is shown to be fast and irreversible, leading to deformation and partial melting of the double helix as a result of π–π stacking between the terminal nucleobases and graphene. Denaturation occurs primarily at the termini, with ensemble averaged H-bond ratios of 47.8–62%; these can, however, reach a minimum of 15%. Transition between free-energy minima occurs via a thermodynamical pathway driving the nucleic acid from a radius of gyration of 1.5 nm to 1.35 nm. Mobility along the basal plane of graphene is dominant, accounting for ~90% of all centre-of-mass translation and revealing that the DNA’s apparent diffusivity is similar to diffusion along the endohedral volume of carbon nanotubes, but one order of magnitude faster than in other 2D materials, such as BC3 and C3N.
{"title":"Partial Denaturation of Double-Stranded DNA on Pristine Graphene under Physiological-like Conditions","authors":"Fernando J. A. L. Cruz, J. Mota","doi":"10.3390/liquids3020013","DOIUrl":"https://doi.org/10.3390/liquids3020013","url":null,"abstract":"Interactions between DNA and graphene are paramount for a wide range of applications, such as biosensing and nanoelectronics; nonetheless, the molecular details of such interactions remain largely unexplored. We employ atomically detailed molecular dynamics simulations with an enhanced sampling technique to investigate the adsorption and mobility of double-stranded DNA along the basal plane of graphene, in an electrolytic aqueous medium. The study focuses on physiologically relevant conditions, using a buffer of [NaCl] = 134 mM. DNA physisorption is shown to be fast and irreversible, leading to deformation and partial melting of the double helix as a result of π–π stacking between the terminal nucleobases and graphene. Denaturation occurs primarily at the termini, with ensemble averaged H-bond ratios of 47.8–62%; these can, however, reach a minimum of 15%. Transition between free-energy minima occurs via a thermodynamical pathway driving the nucleic acid from a radius of gyration of 1.5 nm to 1.35 nm. Mobility along the basal plane of graphene is dominant, accounting for ~90% of all centre-of-mass translation and revealing that the DNA’s apparent diffusivity is similar to diffusion along the endohedral volume of carbon nanotubes, but one order of magnitude faster than in other 2D materials, such as BC3 and C3N.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"38 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89459253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-13DOI: 10.1080/00319104.2023.2185618
Vijaya Lakshmi Chaduvula, M. Gowrisankar, R. Balaji, D. Ramachandran
ABSTRACT Excess molar volumes (V E), excess acoustic impedance (Z E), excess isentropic compressibility (κ s E), deviation in viscosity (Δη), excess Gibbs energy of activation of viscous flow (G *E), excess free length (L f E), excess enthalpy (H E) and excess speed of sound (U E) for binary mixtures of 2-methyl-1-propanol with meta-substituted aniline (3-chloroaniline, 3-methoxyaniline and 3-methylaniline) at selected compositions were determined from the measured values of densities (ρ), viscosities (η) and speeds of sound (u) of pure components and their mixtures in range of 303.15–313.15 K. The results are analysed in terms of interactions arising due to the formation of complex hydrogen bond electron in the binary mixtures. Different theoretical models were applied to check the applicability to the present values of speed of sound and viscosity. Finally, the Prigogine–Flory–Patterson theory is applied to identify the most predominant molecular interaction.
{"title":"Study of molecular interactions between 2-methyl 1-propanol and m-substituted aniline at various temperatures (thermodynamic and acoustic properties)","authors":"Vijaya Lakshmi Chaduvula, M. Gowrisankar, R. Balaji, D. Ramachandran","doi":"10.1080/00319104.2023.2185618","DOIUrl":"https://doi.org/10.1080/00319104.2023.2185618","url":null,"abstract":"ABSTRACT Excess molar volumes (V E), excess acoustic impedance (Z E), excess isentropic compressibility (κ s E), deviation in viscosity (Δη), excess Gibbs energy of activation of viscous flow (G *E), excess free length (L f E), excess enthalpy (H E) and excess speed of sound (U E) for binary mixtures of 2-methyl-1-propanol with meta-substituted aniline (3-chloroaniline, 3-methoxyaniline and 3-methylaniline) at selected compositions were determined from the measured values of densities (ρ), viscosities (η) and speeds of sound (u) of pure components and their mixtures in range of 303.15–313.15 K. The results are analysed in terms of interactions arising due to the formation of complex hydrogen bond electron in the binary mixtures. Different theoretical models were applied to check the applicability to the present values of speed of sound and viscosity. Finally, the Prigogine–Flory–Patterson theory is applied to identify the most predominant molecular interaction.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"65 1","pages":"217 - 225"},"PeriodicalIF":1.2,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84369590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-12DOI: 10.1080/00319104.2023.2188213
F. Aliaj, Arber Zeqiraj
ABSTRACT This work reports experimental densities and sound speeds at (293.15, 298.15, 303.15, 308.15, and 313.15) K and viscosities at 298.15 K for the binary liquid mixtures methanol + pyridine, methanol + benzene, and pyridine + benzene over the entire range of compositions and atmospheric pressure. The excess properties, namely the excess molar volume , excess isentropic compressibility , and excess Gibbs energy for activation of viscous flow G* E were calculated from experimental data and are fitted to Redlich-Kister polynomials. The results obtained were discussed in terms of molecular interactions between the mixing components and structural effects.
{"title":"Thermodynamic excess properties of binary mixtures of methanol + pyridine, methanol + benzene, and pyridine + benzene at several temperatures and atmospheric pressure","authors":"F. Aliaj, Arber Zeqiraj","doi":"10.1080/00319104.2023.2188213","DOIUrl":"https://doi.org/10.1080/00319104.2023.2188213","url":null,"abstract":"ABSTRACT This work reports experimental densities and sound speeds at (293.15, 298.15, 303.15, 308.15, and 313.15) K and viscosities at 298.15 K for the binary liquid mixtures methanol + pyridine, methanol + benzene, and pyridine + benzene over the entire range of compositions and atmospheric pressure. The excess properties, namely the excess molar volume , excess isentropic compressibility , and excess Gibbs energy for activation of viscous flow G* E were calculated from experimental data and are fitted to Redlich-Kister polynomials. The results obtained were discussed in terms of molecular interactions between the mixing components and structural effects.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"82 1","pages":"240 - 252"},"PeriodicalIF":1.2,"publicationDate":"2023-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77020424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-10DOI: 10.1080/00319104.2023.2188212
S. H. Saknure, Nitin. P. Garad, A. G. Gubre, Y. S. Joshi, A. Kumbharkhane
ABSTRACT Time Domain Reflectometry (TDR) and frequency domain techniques have been used for the dielectric measurement of methyl cellulose (MC) with water for different concentrations and frequency ranges from 20 Hz to 2 MHz and 10 MHz to 30 GHz at 25°C. The dielectric relaxation in these mixtures can be represented by the Debye relaxation behaviour. The dielectric parameters such as complex permittivity ε*(ω), complex electrical modulus M*(ω), complex electrical conductivity σ*(ω), loss tangent (tan δ), static dielectric constant (ε0) and relaxation time (τ) have been determined. The variation of dielectric parameters of methyl cellulose (MC) in water suggested that methyl cellulose (MC) bonds with water alter its structure and electric dipole moment.
{"title":"Molecular interactions studies of methyl cellulose-water solutions using dielectric spectroscopy","authors":"S. H. Saknure, Nitin. P. Garad, A. G. Gubre, Y. S. Joshi, A. Kumbharkhane","doi":"10.1080/00319104.2023.2188212","DOIUrl":"https://doi.org/10.1080/00319104.2023.2188212","url":null,"abstract":"ABSTRACT Time Domain Reflectometry (TDR) and frequency domain techniques have been used for the dielectric measurement of methyl cellulose (MC) with water for different concentrations and frequency ranges from 20 Hz to 2 MHz and 10 MHz to 30 GHz at 25°C. The dielectric relaxation in these mixtures can be represented by the Debye relaxation behaviour. The dielectric parameters such as complex permittivity ε*(ω), complex electrical modulus M*(ω), complex electrical conductivity σ*(ω), loss tangent (tan δ), static dielectric constant (ε0) and relaxation time (τ) have been determined. The variation of dielectric parameters of methyl cellulose (MC) in water suggested that methyl cellulose (MC) bonds with water alter its structure and electric dipole moment.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":" 26","pages":"229 - 239"},"PeriodicalIF":1.2,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72382888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Idney Brandão, T. L. Fonseca, H. C. Georg, M. A. Castro, R. B. Pontes
Using the ASEC-FEG approach in combination with atomistic simulations, we performed geometry optimizations of a Cs conformer of the lithium decahydroborate (Li@B10H14) complex in chloroform and in water, which has been shown to be the most stable in the gas phase and calculated its first hyperpolarizability. At room temperature, ASEC-FEG calculations show that this conformer is stable only in chloroform. However, it is found that the nonlinear response of the Cs conformer in chloroform is mild, and the result for the hyperpolarizability is markedly decreased in comparison with the result of the C2v conformer.
{"title":"Conformational Dependence of the First Hyperpolarizability of the Li@B10H14 in Solution","authors":"Idney Brandão, T. L. Fonseca, H. C. Georg, M. A. Castro, R. B. Pontes","doi":"10.3390/liquids3010012","DOIUrl":"https://doi.org/10.3390/liquids3010012","url":null,"abstract":"Using the ASEC-FEG approach in combination with atomistic simulations, we performed geometry optimizations of a Cs conformer of the lithium decahydroborate (Li@B10H14) complex in chloroform and in water, which has been shown to be the most stable in the gas phase and calculated its first hyperpolarizability. At room temperature, ASEC-FEG calculations show that this conformer is stable only in chloroform. However, it is found that the nonlinear response of the Cs conformer in chloroform is mild, and the result for the hyperpolarizability is markedly decreased in comparison with the result of the C2v conformer.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"101 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77345219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Cavers, Julien Steffen, N. Gogoi, R. Adelung, B. Hartke, S. Hansen
The initial formation cycles are critical to the performance of a lithium-ion battery (LIB), particularly in the case of silicon anodes, where the high surface area and extreme volume expansion during cycling make silicon susceptible to detrimental side reactions with the electrolyte. The solid electrolyte interface (SEI) that is formed during these initial cycles serves to protect the surface of the anode from a continued reaction with the electrolyte, and its composition reflects the composition of the electrolyte. In this work, ReaxFF reactive force field simulations were used to investigate the interactions between ether-based electrolytes with high LiTFSI salt concentrations (up to 4 mol/L) and a silicon oxide surface. The simulation investigations were verified with galvanostatic testing and post-mortem X-ray photoelectron spectroscopy, revealing that highly concentrated electrolytes resulted in the faster formation and SEIs containing more inorganic and silicon species. This study emphasizes the importance of understanding the link between electrolyte composition and SEI formation. This ReaxFF approach demonstrates an accessible way to tune electrolyte compositions for optimized performance without costly, time-consuming experimentation.
{"title":"Investigation of the Impact of High Concentration LiTFSI Electrolytes on Silicon Anodes with Reactive Force Field Simulations","authors":"H. Cavers, Julien Steffen, N. Gogoi, R. Adelung, B. Hartke, S. Hansen","doi":"10.3390/liquids3010011","DOIUrl":"https://doi.org/10.3390/liquids3010011","url":null,"abstract":"The initial formation cycles are critical to the performance of a lithium-ion battery (LIB), particularly in the case of silicon anodes, where the high surface area and extreme volume expansion during cycling make silicon susceptible to detrimental side reactions with the electrolyte. The solid electrolyte interface (SEI) that is formed during these initial cycles serves to protect the surface of the anode from a continued reaction with the electrolyte, and its composition reflects the composition of the electrolyte. In this work, ReaxFF reactive force field simulations were used to investigate the interactions between ether-based electrolytes with high LiTFSI salt concentrations (up to 4 mol/L) and a silicon oxide surface. The simulation investigations were verified with galvanostatic testing and post-mortem X-ray photoelectron spectroscopy, revealing that highly concentrated electrolytes resulted in the faster formation and SEIs containing more inorganic and silicon species. This study emphasizes the importance of understanding the link between electrolyte composition and SEI formation. This ReaxFF approach demonstrates an accessible way to tune electrolyte compositions for optimized performance without costly, time-consuming experimentation.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"5 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87382331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abraham model solute descriptors are reported for the first time for 62 additional C10 through C13 methyl- and ethyl-branched alkanes. The numerical values were determined using published gas chromatographic retention Kováts retention indices for 157 alkane solutes eluted from a squalane stationary phase column. The 95 alkane solutes that have known descriptor values were used to construct the Abraham model KRI versus L-solute descriptor correlation needed in our calculations. The calculated solute descriptors can be used in conjunction with previously published Abraham model correlations to predict a wide range of important physico-chemical and biological properties. The predictive computations are illustrated by estimating the air-to-polydimethylsiloxane partition coefficient for each of the 157 alkane solutes.
{"title":"Determination of Abraham Model Solute Descriptors for 62 Additional C10 through C13 Methyl- and Ethyl-Branched Alkanes","authors":"Ramya Motati, W. Acree","doi":"10.3390/liquids3010010","DOIUrl":"https://doi.org/10.3390/liquids3010010","url":null,"abstract":"Abraham model solute descriptors are reported for the first time for 62 additional C10 through C13 methyl- and ethyl-branched alkanes. The numerical values were determined using published gas chromatographic retention Kováts retention indices for 157 alkane solutes eluted from a squalane stationary phase column. The 95 alkane solutes that have known descriptor values were used to construct the Abraham model KRI versus L-solute descriptor correlation needed in our calculations. The calculated solute descriptors can be used in conjunction with previously published Abraham model correlations to predict a wide range of important physico-chemical and biological properties. The predictive computations are illustrated by estimating the air-to-polydimethylsiloxane partition coefficient for each of the 157 alkane solutes.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"41 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90249502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we proceed to illustrate the consequences and implications of the Dual Model of Liquids (DML) by applying it to the heat propagation. Within the frame of the DML, propagation of thermal (elastic) energy in liquids is due to wave-packet propagation and to the wave-packets’ interaction with the material particles of the liquid, meant in the DML as aggregates of molecules swimming in an ocean of amorphous liquid. The liquid particles interact with the lattice particles, a population of elastic wave-packets, by means of an inertial force, exchanging energy and momentum with them. The hit particle relaxes at the end of the interaction, releasing the energy and momentum back to the system a step forward and a time lapse later, like in a tunnel effect. The tunnel effect and the duality of liquids are the new elements that suggest on a physical basis for the first time, using a hyperbolic equation to describe the propagation of energy associated to the dynamics of wave-packet interaction with liquid particles. Although quantitatively relevant only in the transient phase, the additional term characterizing the hyperbolic equation, usually named the “memory term”, is physically present also once the stationary state is attained; it is responsible for dissipation in liquids and provides a finite propagation velocity for wave-packet avalanches responsible in the DML for the heat conduction. The consequences of this physical interpretation of the “memory” term added to the Fourier law for the phononic contribution are discussed and compiled with numerical prediction for the value of the memory term and with the conclusions of other works on the same topic.
{"title":"How Does Heat Propagate in Liquids?","authors":"F. Peluso","doi":"10.3390/liquids3010009","DOIUrl":"https://doi.org/10.3390/liquids3010009","url":null,"abstract":"In this paper, we proceed to illustrate the consequences and implications of the Dual Model of Liquids (DML) by applying it to the heat propagation. Within the frame of the DML, propagation of thermal (elastic) energy in liquids is due to wave-packet propagation and to the wave-packets’ interaction with the material particles of the liquid, meant in the DML as aggregates of molecules swimming in an ocean of amorphous liquid. The liquid particles interact with the lattice particles, a population of elastic wave-packets, by means of an inertial force, exchanging energy and momentum with them. The hit particle relaxes at the end of the interaction, releasing the energy and momentum back to the system a step forward and a time lapse later, like in a tunnel effect. The tunnel effect and the duality of liquids are the new elements that suggest on a physical basis for the first time, using a hyperbolic equation to describe the propagation of energy associated to the dynamics of wave-packet interaction with liquid particles. Although quantitatively relevant only in the transient phase, the additional term characterizing the hyperbolic equation, usually named the “memory term”, is physically present also once the stationary state is attained; it is responsible for dissipation in liquids and provides a finite propagation velocity for wave-packet avalanches responsible in the DML for the heat conduction. The consequences of this physical interpretation of the “memory” term added to the Fourier law for the phononic contribution are discussed and compiled with numerical prediction for the value of the memory term and with the conclusions of other works on the same topic.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"19 4 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89657600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-30DOI: 10.1080/00319104.2023.2168664
Afef Ben Yahya, E. Cherif
ABSTRACT Biopolymers are common ingredients in medical, technological, and industrial products. This paper presents the experimental analysis of conductometric properties of polysaccharides of chitosan (CH) in solutions in water W. The electrical conductivity was measured under the influence of increasing concentration of (0.5 to 10) g/l and increasing temperature of (288.15 to 318.15) K. The reduced electrical conductivity and the activation energy of reduced electrical conductivity Eσ are calculated. Biopolymer solutions exhibit a critical recovery of intrinsic electrical conductivity and a critical concentration c*, separating solutions into dilute solutions and semi-dilute solutions. The dependencies of the activation energy with solution concentration and intrinsic electrical conductivity are discussed. The polysaccharide CH behaviour can be extrapolated from the Flory-Huggins theory by decomposing such as . Where the is the entropy-originated term that reflects the tendency of molecules to adopt as many configurations as possible on the network and the is associated with the energy variation that occurs when two molecules of different species are brought into contact. This enthalpy contribution represents well the non-Arrhenius behaviour. Principles that aid one to understand and interpret such results are discussed.
{"title":"Elaboration, synthesis and characterisation by conductometric study of chitosan materials in water","authors":"Afef Ben Yahya, E. Cherif","doi":"10.1080/00319104.2023.2168664","DOIUrl":"https://doi.org/10.1080/00319104.2023.2168664","url":null,"abstract":"ABSTRACT Biopolymers are common ingredients in medical, technological, and industrial products. This paper presents the experimental analysis of conductometric properties of polysaccharides of chitosan (CH) in solutions in water W. The electrical conductivity was measured under the influence of increasing concentration of (0.5 to 10) g/l and increasing temperature of (288.15 to 318.15) K. The reduced electrical conductivity and the activation energy of reduced electrical conductivity Eσ are calculated. Biopolymer solutions exhibit a critical recovery of intrinsic electrical conductivity and a critical concentration c*, separating solutions into dilute solutions and semi-dilute solutions. The dependencies of the activation energy with solution concentration and intrinsic electrical conductivity are discussed. The polysaccharide CH behaviour can be extrapolated from the Flory-Huggins theory by decomposing such as . Where the is the entropy-originated term that reflects the tendency of molecules to adopt as many configurations as possible on the network and the is associated with the energy variation that occurs when two molecules of different species are brought into contact. This enthalpy contribution represents well the non-Arrhenius behaviour. Principles that aid one to understand and interpret such results are discussed.","PeriodicalId":20094,"journal":{"name":"Physics and Chemistry of Liquids","volume":"2 1","pages":"202 - 216"},"PeriodicalIF":1.2,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89608941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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