Polymer Nanoscience: Glass Transition in Copolymers and Confined Colloidal Processing

Rodney D. Priestley

Chemical and Biological Engineering

Princeton Institute for the Science and Technology of Materials

Princeton University, Princeton, NJ, 08544 USA


In this talk, I discuss two important themes in contemporary polymer science: nanoscale
confinement effects on polymer properties and new routes of processing nanomaterials, i.e.,
nanoparticles. Concerning the former, significant effort has been devoted to pursing an
understanding of the glass transition temperature of polymers confined to the nanoscale. Much
of our understanding has been obtained via studies on thin polymer films. Here, we show that in
di-block copolymers there can exist a substantial gradient in glassy dynamics by directly
measuring of the glass transition temperature at discrete locations away from the block
copolymer interface. The results can be well described by the Lodge-McLeish representation of
self-concentration. With regards to the later theme, we will demonstrate a strategy for the self-
assembly of multi-faced nanoparticles through the precipitation-induced, rapid spinodal-
decomposition of polymer phases within a confined solution volume. Using a two-faced Janus
particle assembled from two simple homopolymers as a model system, we demonstrate the
ability of the method to provide simultaneous control over particle size, surface functionality,
and compositional anisotropy as the assembly process is scaled. Our results demonstrate that
incompatible polymers with different properties can be self-assembled into nanoparticles with
controllable surface topology by simultaneously reducing the timescale and solution volume over
which they undergo self-assembly.

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