Smectic C and Nematic Phases in Strongly Adsorbed Layers of Semiflexible Polymers

Molecular
dynamics simulations of semiflexible polymers in a good solvent reveal
a dense adsorbed layer when the solution is exposed to an attractive
planar wall. This layer exhibits both a nematic and a smectic phase
(smA for short and smC for longer chains) with bond vectors aligned
strictly parallel to the wall. The tilt angle of the smC phase increases
strongly with the contour length of the polymers. The isotropic–nematic
transition is a Kosterlitz–Thouless transition and also the
nematic–smectic transition is continuous. Our finding demonstrates
thus a two-dimensional realization of different liquid crystalline
phases, ubiquitous in three dimensions, that occurs in a single monomolecular
layer ordered at least over mesoscopic scales.