Polymer Brushes for Molecular Transport - Paul Braun Research ...

controlling surface properties.[1-8] In our study, surface-initiated polymerization, i.e. both
homopolymerization and copolymerization, of a wide variety of monomers can be applied to
fulfill an extensive spectrum of surface and bulk properties of the polymer brushes, and therefore
achieve a full library of diffusion behaviors using these polymer brushes for molecular transport.
As schematically demonstrated in Figure 1.1, patterned polymer brushes of different chemical
structures can be used to direct the diffusion of different molecules and ions and thus accomplish
the goal of surface-directed molecular separation.
Figure 1.1. Schematic representation of patterned polymer brushes for directing molecular and
ionic diffusion.
As a starting point, it is interesting to study the 2-dimensional (2-D), solid-state diffusion
of small organic fluorophores in surface-bound polymer brushes of homopolymers. Molecular
diffusion in solid-state polymer thin films is closely relevant to the potential applications of end-
grafted polymers as photoresists for micro- and nano-electronics, antifriction coatings, protection
layers against oxidation or other chemical reactions, adhesion layers, and biocompatible surfaces
for medical devices.[3, 9, 10] Since the polymer brushes are covalently attached to the substrate
and they are in solid state, the probe diffusion is occurring in an immobile 2-D matrix, and this is
2
end-grafted polymers