Advanced

Density Functional Study of Surface Forces in Athermal Polymer Solutions with Addititve Hard Sphere Interactions. Solvent Effects, Capillary Condensation and Capillary-Induced Surface Transitions.

Forsman, Jan LU ; Woodward, Clifford E. and Freasier, Ben C. (2002) In Journal of Chemical Physics 117(4). p.1915-1926
Abstract
A density functional theory for polymer solutions is generalized to cases where the monomers have

a different diameter to the solvent. An appropriate free energy functional is obtained by integration

of the generalized Flory equation of state for such systems. This functional predicts that entropic

demixing may occur in polymer solutions in which the solvent particles are smaller than the

monomers. Demixing is promoted not only by a large size disparity, but also by a high pressure as

well as by polymer length. The existence of two separate phases in the bulk solution suggests the

possibility of capillary-induced phase transitions, even when the confining surfaces are hard, ... (More)
A density functional theory for polymer solutions is generalized to cases where the monomers have

a different diameter to the solvent. An appropriate free energy functional is obtained by integration

of the generalized Flory equation of state for such systems. This functional predicts that entropic

demixing may occur in polymer solutions in which the solvent particles are smaller than the

monomers. Demixing is promoted not only by a large size disparity, but also by a high pressure as

well as by polymer length. The existence of two separate phases in the bulk solution suggests the

possibility of capillary-induced phase transitions, even when the confining surfaces are hard, but

otherwise inert. We examine such phase transitions and their relation to surface forces and colloidal

stability. The density functional theory also predicts that under certain conditions, layering

transitions will occur at hard and flat surfaces. A transition from a thin to a thick polymer-rich

surface layer may take place as the separation between two surfaces is decreased, and we study the

concomitant change on the surface force. Stable thick phases are predicted even at very large

undersaturations, and they give rise to a profound increase of the range and strength of the surface

force.We furthermore include comparisons with predictions from a model in which the solvent only

enters the description implicitly. Responses of the surface forces to changes in monomer diameter,

solvent diameter, polymer density, and chain length are investigated. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Physics
volume
117
issue
4
pages
1915 - 1926
publisher
American Institute of Physics
external identifiers
  • scopus:0037158088
ISSN
0021-9606
DOI
10.1063/1.1486445
language
English
LU publication?
yes
id
8da445dc-9dfb-4882-9e13-93778745445b (old id 995485)
date added to LUP
2008-01-29 17:16:59
date last changed
2017-08-27 03:58:49
@article{8da445dc-9dfb-4882-9e13-93778745445b,
  abstract     = {A density functional theory for polymer solutions is generalized to cases where the monomers have<br/><br>
a different diameter to the solvent. An appropriate free energy functional is obtained by integration<br/><br>
of the generalized Flory equation of state for such systems. This functional predicts that entropic<br/><br>
demixing may occur in polymer solutions in which the solvent particles are smaller than the<br/><br>
monomers. Demixing is promoted not only by a large size disparity, but also by a high pressure as<br/><br>
well as by polymer length. The existence of two separate phases in the bulk solution suggests the<br/><br>
possibility of capillary-induced phase transitions, even when the confining surfaces are hard, but<br/><br>
otherwise inert. We examine such phase transitions and their relation to surface forces and colloidal<br/><br>
stability. The density functional theory also predicts that under certain conditions, layering<br/><br>
transitions will occur at hard and flat surfaces. A transition from a thin to a thick polymer-rich<br/><br>
surface layer may take place as the separation between two surfaces is decreased, and we study the<br/><br>
concomitant change on the surface force. Stable thick phases are predicted even at very large<br/><br>
undersaturations, and they give rise to a profound increase of the range and strength of the surface<br/><br>
force.We furthermore include comparisons with predictions from a model in which the solvent only<br/><br>
enters the description implicitly. Responses of the surface forces to changes in monomer diameter,<br/><br>
solvent diameter, polymer density, and chain length are investigated.},
  author       = {Forsman, Jan and Woodward, Clifford E. and Freasier, Ben C.},
  issn         = {0021-9606},
  language     = {eng},
  number       = {4},
  pages        = {1915--1926},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Density Functional Study of Surface Forces in Athermal Polymer Solutions with Addititve Hard Sphere Interactions. Solvent Effects, Capillary Condensation and Capillary-Induced Surface Transitions.},
  url          = {http://dx.doi.org/10.1063/1.1486445},
  volume       = {117},
  year         = {2002},
}