Surface forces at restricted equilibrium, in solutions containing finite or infinite semiflexible polymers
(2007) In Macromolecules 40(23). p.83968408 Abstract
 We use density functional theory to investigate how the presence of polymers influence the interactions between adsorbing or nonadsorbing flat surfaces, forming a slit geometry. The study is primarily made under "restricted equilibrium" conditions, i.e., below a threshold separation, the chains are allowed to equilibrate conformationally between the surfaces, but they are unable to diffuse into or out from the slit. This is believed to be a reasonable model for commonly encountered experimental situations, when the surfaces are large and adsorbing and the polymers are long. Using a recently presented density functional theory, we are able to compare predictions for chains of finite and infinite length. A major advantage of the infinite... (More)
 We use density functional theory to investigate how the presence of polymers influence the interactions between adsorbing or nonadsorbing flat surfaces, forming a slit geometry. The study is primarily made under "restricted equilibrium" conditions, i.e., below a threshold separation, the chains are allowed to equilibrate conformationally between the surfaces, but they are unable to diffuse into or out from the slit. This is believed to be a reasonable model for commonly encountered experimental situations, when the surfaces are large and adsorbing and the polymers are long. Using a recently presented density functional theory, we are able to compare predictions for chains of finite and infinite length. A major advantage of the infinite chain formulation is that it is a high resolution theory, and predictions from the finite length version will exactly approach the ones for infinite chains, when the degree of polymerization becomes large enough. Our study spans across a relatively large number of relevant system parameters, such as bulk concentration, surface adsorption strength, polymer length, and chain flexibility. The response in terms of the net surface interaction, to a change of a system parameter, is often nonmonotonic. We also make comparisons with predictions it full equilibrium, where the diffusion constraint has been relaxed. We give a specific example of how a diffusionlimited process can lead to hysteresis effects, similar to those observed in many surface force measurements. Finally, in a separate section of this work, we have included some direct experimental comparisons, demonstrating the relevance and applicability of restricted equilibrium conditions to "real world" scenarios. The computational power of the density functional approach is here highlighted, with calculations including semiflexible 20000mers. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/971855
 author
 Forsman, Jan ^{LU} and Woodward, Clifford E.
 organization
 publishing date
 2007
 type
 Contribution to journal
 publication status
 published
 subject
 in
 Macromolecules
 volume
 40
 issue
 23
 pages
 8396  8408
 publisher
 The American Chemical Society
 external identifiers

 wos:000250801700040
 scopus:36349002935
 ISSN
 00249297
 DOI
 10.1021/ma071181t
 language
 English
 LU publication?
 yes
 id
 f7a7d8dd7464460ebe4fdecb7bb5d4fd (old id 971855)
 date added to LUP
 20080129 15:05:28
 date last changed
 20170101 04:21:26
@article{f7a7d8dd7464460ebe4fdecb7bb5d4fd, abstract = {We use density functional theory to investigate how the presence of polymers influence the interactions between adsorbing or nonadsorbing flat surfaces, forming a slit geometry. The study is primarily made under "restricted equilibrium" conditions, i.e., below a threshold separation, the chains are allowed to equilibrate conformationally between the surfaces, but they are unable to diffuse into or out from the slit. This is believed to be a reasonable model for commonly encountered experimental situations, when the surfaces are large and adsorbing and the polymers are long. Using a recently presented density functional theory, we are able to compare predictions for chains of finite and infinite length. A major advantage of the infinite chain formulation is that it is a high resolution theory, and predictions from the finite length version will exactly approach the ones for infinite chains, when the degree of polymerization becomes large enough. Our study spans across a relatively large number of relevant system parameters, such as bulk concentration, surface adsorption strength, polymer length, and chain flexibility. The response in terms of the net surface interaction, to a change of a system parameter, is often nonmonotonic. We also make comparisons with predictions it full equilibrium, where the diffusion constraint has been relaxed. We give a specific example of how a diffusionlimited process can lead to hysteresis effects, similar to those observed in many surface force measurements. Finally, in a separate section of this work, we have included some direct experimental comparisons, demonstrating the relevance and applicability of restricted equilibrium conditions to "real world" scenarios. The computational power of the density functional approach is here highlighted, with calculations including semiflexible 20000mers.}, author = {Forsman, Jan and Woodward, Clifford E.}, issn = {00249297}, language = {eng}, number = {23}, pages = {83968408}, publisher = {The American Chemical Society}, series = {Macromolecules}, title = {Surface forces at restricted equilibrium, in solutions containing finite or infinite semiflexible polymers}, url = {http://dx.doi.org/10.1021/ma071181t}, volume = {40}, year = {2007}, }