Document Detail


Osmotic pressure and virial coefficients of star and comb polymer solutions: dissipative particle dynamics.
MedLine Citation:
PMID:  19334886     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
The effects of macromolecular architecture on the osmotic pressure pi and virial coefficients (B(2) and B(3)) of star and comb polymers in good solvents are studied by dissipative particle dynamics simulations for both dilute and semiconcentrated regimes. The dependence of the osmotic pressure on polymer concentration is directly calculated by considering two reservoirs separated by a semipermeable, fictitious membrane. Our simulation results show that the ratios A(n+1) identical with B(n+1)/R(g)(3n) are essentially constant and A(2) and A(3) are arm number (f) dependent, where R(g) is zero-density radius of gyration. The value of dimensionless virial ratio g = A(3)/A(2)(2) increases with arm number of stars whereas it is essentially arm number independent for comb polymers. In semiconcentrated regime the scaling relation between osmotic pressure and volume fraction, pi proportional to phi(lambda), still holds for both star and comb polymers. For comb polymers, the exponent lambda is close to lambda(*) (approximately = 2.73 for linear chains) and is independent of the arm number. However, for star polymers, the exponent lambda deviates from lambda(*) and actually grows with increasing the arm number. This may be attributed to the significant ternary interactions near the star core in the many-arm systems.
Authors:
Tzu-Yu Wang; Che-Ming Fang; Yu-Jane Sheng; Heng-Kwong Tsao
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of chemical physics     Volume:  130     ISSN:  1089-7690     ISO Abbreviation:  J Chem Phys     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-04-01     Completed Date:  2009-08-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0375360     Medline TA:  J Chem Phys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  124904     Citation Subset:  -    
Affiliation:
Department of Chemical and Materials Engineering, National Central University, Jhongli, Taiwan 320.
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