Thermogravitational Thermal Diffusion in Liquid Polymer Solutions

Ecenarro, O.; Madariaga, J. A.; Navarro, J. L.; Santamaría, Carlos; Carrión, Juan Andrés Cárcel; Savirón, J. M.

doi:10.1021/ma00096a018

Cited by 30 publications

(29 citation statements)

References 5 publications

(5 reference statements)

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“…Among liquids, investigations have been made for hydrocarbons [20,89e92], associating mixtures [93], polymers [94] as well as ferrofluids [95e98]. …”

Section: Thermogravitational Column (Tgc)mentioning

confidence: 99%

Experimental approaches to study thermodiffusion – A review

Srinivasan

Saghir

2011

International Journal of Thermal Sciences

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“…Among liquids, investigations have been made for hydrocarbons [20,89e92], associating mixtures [93], polymers [94] as well as ferrofluids [95e98]. …”

Section: Thermogravitational Column (Tgc)mentioning

confidence: 99%

Experimental approaches to study thermodiffusion – A review

Srinivasan

Saghir

2011

International Journal of Thermal Sciences

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“…The most recent investigations show that the behavior of Sr versus concentration is essentially controlled by that of the ordinary diffusion D which increases significantly with increasing concentrations. The concentration dependence of the thermodiffusion coefficient Dr is much lower than that of D. Dr is found to either weakly increase [30] or weakly decrease [28,31,32] with increasing concentrations.…”

Section: Influence Of Sample Amount On Soret Coefficientmentioning

confidence: 99%

Experimental study of the concentration dependence of the soret coefficient by thermal field-flow fractionation: the case of polystyrene in decalin

et al. 2002

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SummaryThermal field-flow fractionation separates poJymers with high selectivity according to their Soret coefficient, ST, hence, according to their molar mass, and therefore consitutes an efficient physicochemical tool for the determination of the Sorer coefficient of a given polymer in the carrier liquid from its retention time. However, the polymer concentration in the sample influences the retention time and, hence, the value of ST derived from it. An experimental study of the influence of sample concentration on retention, ST, and peak shape was performed for the polystyrene-decahn system over a relatively large temperature domain and for various molar masses.It is found that the retention time and the value of ST increase with increasing sample concentration, the more so as the cold wall temperature is lower. This appears to be in contradiction with the general non-equilibrium thermodynamic expression derived for polymer-solvent systems with positive second virial coefficients, such as the present system over the temperature range investigated. There seems to be a temperature for which the dependence of S T on sample concentration vanishes. This temperature is about 375 K for the polysb, rene-decalin system.As the sample concentration increases, the peak barycentre and the standard deviation increases. As the peaks are fronting, the skewness is negative and becomes more negative as the sample concentration increases. The peak skewness appears to be a good indicator of the onset of sample concentration effects. The threshold concentration, forwhich these effects begin to become significant, decreases with increasing molar mass.

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“…In general for organic polymer solutions, the polymers due to their heavier mass and larger size compared to the solvent molecules move to the cold side. [16][17][18][19] Some aqueous solutions of polymers show negative Soret coefficients, which correspond to a migration of the polymers to the warm side. [20][21][22][23][24][25] It has been revealed that a sign of S T of the polymer in solution can occur as function of the solution temperature as well as of the solvent composition.…”

Section: Introductionmentioning

confidence: 99%