The name is absent

segment j (in a linear ideal chain of m segments) is given by

Pj(*j) = θxp(⅜w) I-I dr_l..dr_j^dr_j+l..dr_mexp[-β'^Vβ^xt(r_i)]exp[-β'^^^∖r_i+l-r_i∖)].
JJ                       _{i=1             i=1}

(4.38)
Comparing this with eqn. 4.37 shows that modified iSAFT gives the exact density
profile for a linear ideal chain in an external field.

4.3.2 Lipids

Lipids play an important role in biological systems. They are categorized by a
polar head group which is hydrophilic and long hydrocarbon tail groups which are hy-
drophobic in nature. Due to the difference in these interactions, these spontaneously
form bilayers when placed in an aqueous medium. In an aqueous milieu, the polar
head groups tend to orient themselves towards the solvent while hydrocarbon tail
groups hide themselves from the solvent. This lead to formation of lipid bilayers or
micelles, see fig. 4.2a. Biological membranes are a form of lipid bilayer.

Recently, Frischknecht and Frink [118] applied molecular dynamics simulation and
the Chandler McCoy Singer (CMS) density functional theory [98, 99] to study lipid
bilayers. The lipid model used consisted of a freely jointed chain of tangent spheres
with a head group and two tail groups. The head is composed of two segments while
each tail has eight smaller segments, as shown in fig. 4.2b. The ratio of head to tail
segment diameters is chosen to be σh∕σ_t = 1.44 on the basis of previous theoretical
work on lipid models [119] which result in lamellar and bilayer forming lipids. The

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