Summary: The adoption of plastic materials in many application areas relies on
their useful combinations of physical properties including ease of
processing, light weight, strength, flexibility, and insulating/dielectric
characteristics. These properties, in turn, depend on the structure or
"morphology" of the material on length scales varying from nanometers
(nm) to microns and larger.
A very useful morphology in polymer science, which underpins the
design of advanced plastic materials, is the so-called "bi-continuous"
morphology. In such a morphology, as shown at right, two polymer
phases (colored red and blue) are three-dimensionally continuous
(connected) throughout the material. This structure allows for passage
of electrons, ions or small molecules through one or both phases, while
still providing mechanical integrity. It is thus of great interest in high-
tech applications such as fuel cell and battery membranes, scaffolds for
tissue engineering, and organic photovoltaic devices.
B. J. Kim, G. H. Fredrickson, C. J. Hawker, and E. J. Kramer
working in UCSB's Materials Research Lab have shown that simple
diblock copolymers (the red-blue polymer at upper left) can be induced
to form stable 10 nm scale bi-continuous morphologies when mixed
with interfacially-active nanoparticles (yellow). This unexpected finding