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Title: Entropy-induced separation of star polymers in porous media

Abstract

We present a quantitative picture of the separation of star polymers in a solution where part of the volume is influenced by a porous medium. To this end, we study the impact of long-range-correlated quenched disorder on the entropy and scaling properties of f-arm star polymers in a good solvent. We assume that the disorder is correlated on the polymer length scale with a power-law decay of the pair correlation function g(r){approx}r{sup -a}. Applying the field-theoretical renormalization group approach we show in a double expansion in {epsilon}=4-d and {delta}=4-a that there is a range of correlation strengths {delta} for which the disorder changes the scaling behavior of star polymers. In a second approach we calculate for fixed space dimension d=3 and different values of the correlation parameter a the corresponding scaling exponents {gamma}{sub f} that govern entropic effects. We find that {gamma}{sub f}-1, the deviation of {gamma}{sub f} from its mean field value is amplified by the disorder once we increase {delta} beyond a threshold. The consequences for a solution of diluted chain and star polymers of equal molecular weight inside a porous medium are that star polymers exert a higher osmotic pressure than chain polymers and in general highermore » branched star polymers are expelled more strongly from the correlated porous medium. Surprisingly, polymer chains will prefer a stronger correlated medium to a less or uncorrelated medium of the same density while the opposite is the case for star polymers.« less

Authors:
 [1];  [2];  [3];  [4];  [1];  [5];  [6]
  1. Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 79011 Lviv (Ukraine)
  2. (Germany)
  3. Theoretische Polymerphysik, Universitaet Freiburg, D-79104 Freiburg (Germany)
  4. (Poland)
  5. (Austria)
  6. (Ukraine)
Publication Date:
OSTI Identifier:
21072297
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics; Journal Volume: 74; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevE.74.031801; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CORRELATION FUNCTIONS; CORRELATIONS; DENSITY; ENTROPY; LENGTH; MEAN-FIELD THEORY; MOLECULAR WEIGHT; POLYMERS; POROUS MATERIALS; RENORMALIZATION; SOLUTIONS; SOLVENTS

Citation Formats

Blavats'ka, V., Institut fuer Theoretische Physik, Universitaet Leipzig, D-04109 Leipzig, Ferber, C. von, Complex Systems Research Center, Jagiellonian University, 31007 Cracow, Holovatch, Yu., Institut fuer Theoretische Physik, Johannes Kepler Universitaet Linz, 4040, Linz, and Ivan Franko National University of Lviv, 79005 Lviv. Entropy-induced separation of star polymers in porous media. United States: N. p., 2006. Web. doi:10.1103/PHYSREVE.74.031801.
Blavats'ka, V., Institut fuer Theoretische Physik, Universitaet Leipzig, D-04109 Leipzig, Ferber, C. von, Complex Systems Research Center, Jagiellonian University, 31007 Cracow, Holovatch, Yu., Institut fuer Theoretische Physik, Johannes Kepler Universitaet Linz, 4040, Linz, & Ivan Franko National University of Lviv, 79005 Lviv. Entropy-induced separation of star polymers in porous media. United States. doi:10.1103/PHYSREVE.74.031801.
Blavats'ka, V., Institut fuer Theoretische Physik, Universitaet Leipzig, D-04109 Leipzig, Ferber, C. von, Complex Systems Research Center, Jagiellonian University, 31007 Cracow, Holovatch, Yu., Institut fuer Theoretische Physik, Johannes Kepler Universitaet Linz, 4040, Linz, and Ivan Franko National University of Lviv, 79005 Lviv. Fri . "Entropy-induced separation of star polymers in porous media". United States. doi:10.1103/PHYSREVE.74.031801.
@article{osti_21072297,
title = {Entropy-induced separation of star polymers in porous media},
author = {Blavats'ka, V. and Institut fuer Theoretische Physik, Universitaet Leipzig, D-04109 Leipzig and Ferber, C. von and Complex Systems Research Center, Jagiellonian University, 31007 Cracow and Holovatch, Yu. and Institut fuer Theoretische Physik, Johannes Kepler Universitaet Linz, 4040, Linz and Ivan Franko National University of Lviv, 79005 Lviv},
abstractNote = {We present a quantitative picture of the separation of star polymers in a solution where part of the volume is influenced by a porous medium. To this end, we study the impact of long-range-correlated quenched disorder on the entropy and scaling properties of f-arm star polymers in a good solvent. We assume that the disorder is correlated on the polymer length scale with a power-law decay of the pair correlation function g(r){approx}r{sup -a}. Applying the field-theoretical renormalization group approach we show in a double expansion in {epsilon}=4-d and {delta}=4-a that there is a range of correlation strengths {delta} for which the disorder changes the scaling behavior of star polymers. In a second approach we calculate for fixed space dimension d=3 and different values of the correlation parameter a the corresponding scaling exponents {gamma}{sub f} that govern entropic effects. We find that {gamma}{sub f}-1, the deviation of {gamma}{sub f} from its mean field value is amplified by the disorder once we increase {delta} beyond a threshold. The consequences for a solution of diluted chain and star polymers of equal molecular weight inside a porous medium are that star polymers exert a higher osmotic pressure than chain polymers and in general higher branched star polymers are expelled more strongly from the correlated porous medium. Surprisingly, polymer chains will prefer a stronger correlated medium to a less or uncorrelated medium of the same density while the opposite is the case for star polymers.},
doi = {10.1103/PHYSREVE.74.031801},
journal = {Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics},
number = 3,
volume = 74,
place = {United States},
year = {Fri Sep 15 00:00:00 EDT 2006},
month = {Fri Sep 15 00:00:00 EDT 2006}
}
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  • Separations of CO{sub 2}/CH{sub 4}, CO{sub 2}/N{sub 2}, and O{sub 2}/N{sub 2} mixtures were studied in three porous coordination polymers made of the same carborane ligand and Co(II) nodes. High selectivities for CO{sub 2} over CH{sub 4} (~47) and CO{sub 2} over N{sub 2} (~95) were obtained, especially in the material with coordinated pyridine. Unusual selectivity for O{sub 2} over N{sub 2} (as high as 6.5) was demonstrated in the materials with open Co(II) sites.