The Effects of Polydispersity on the Melt Phase and Aqueous Solution Phase Behavior of ABATriblock C

1
The Effects of Polydispersity on the Melt Phase
and Aqueous Solution Phase Behavior of
ABA-Triblock Copolymers
Mahesh K. Mahanthappa, Department of Chemistry,
University of Wisconsin-Madison
ABA-triblock copolymers and related polymer
surfactants combine two chemically dissimilar
homopolymer segments into a single macromolecule.
Molecules of this type having narrow molecular
weight distributions typically self-assemble into
a variety of nanostructured materials that find
applications as thermoplastic elastomers,
pressure-sensitive adhesives, and as non-ionic
surfactants in cosmetics and in enhanced oil
recovery. We are systematically exploring the
effects of molecular weight polydispersity on the
self-assembly behavior of ABA-type triblock
copolymers having polydisperse B blocks. Our
results show that these materials do
self-assemble into ordered structures with
variable degrees of long-range order. The
polydisperse melts prefer to adopt morphologies
in which the block interfaces curve toward the
polydisperse segment, resulting in dramatic
shifts in the morphology diagram.