APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011;
Dallas, Texas
Abstract: H4.00001 : Polymer Physics Prize Talk: Polymer Brushes: Why do we still care?
8:00 AM–8:36 AM
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Polymer molecules have been widely used to modify the properties
of surfaces including its adhesion. Among the most studied have
been polymer brushes, in which polymer chains are grafted at one
end to a surface and immersed in a small molecule solvents.
Experiments and simulations have shown that the conformation of
the chains grafted onto a flat surface depends on the grafting
density and the interaction of the polymer with the solvent. As
the molecular weight of the solvent increases, the structure of
the brush changes. Consequently the brush chains are expelled
from the solvent due to entropic loss that originate from the
fact that the melt chains penetrating the brush cannot overcome
the translational, or mixing, entropy. This crossover from wetted
to non-wetted brushes, has important implications for polymer
adhesion, where the phase separation of melt and brush chains
reduces entanglements at the interface. As polymers are grafted
to nanoparticles, the curvature of the surface offers the polymer
brush chains a significantly larger space to explore compared to
a flat surface, reducing the tendency for autophobic dewetting.
Using large scale molecular dynamics simulations we have studied
the interface between brush coated nanoparticles and a polymer
melt. Effects of chain length of the brush, and that of the
polymer melt, the coverage of the nanoparticle and its curvature
on the brush/melt interface will be discussed. The role of
individual entanglements, between the brush chains and the melt,
as identified by primitive path analysis will be introduced.
These simulations provide insight into the structure of the
brush/polymer interface which is not accessible through other
theoretical or experimental means.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.H4.1