monolayers in the presence of free polymer strongly depends upon the conformational
changes of the monolayers as they approach each other. Hence, modified iSAFT is
also applied to study how their structures and the force of interaction changes as they
approach and interpenetrate each other in the absence of free polymer. Next, the free
polymer is added around the monolayers and the effect of free polymer concentration,
grafting density, and ratio of the segment sizes of the grafted and free polymers on
the force of interaction, is investigated.
6.2 Extension of modified iSAFT to grafted poly-
mer chains
The general formulation of modified iSAFT for a fluid of free polymer chains of
‘m’ segments was presented in detail in chapter 4. The equilibrium density profile
({pα(rtt)}) of the segments of the chain in the presence of an external field ({½^t(ra)})
is given by
pα(r) = exp(∕3μ⅛f) exp[L>a(r) - ∕5lζelt(r)]∕ι,α(r)∕2,α(r), (6.1)
where μ⅛f(= ɪɪi AtJ ɪɛ the bulk chemical potential of the polymer chain.
<⅛2^c⅜[{∕⅛(rι)}]
δpsae9(r)
δβAεx^[{pa}] δβAεx'att[{ρa}]
δpsae9(r) δpsae9(r)
(6.2)
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