Filled Polymers

With Turab Lookman, Avadh Saxena, and Jack Douglas

Numerous important industrial applications of polymer blends require both understandings and control of their morphology as well as stability. Polymer materials are seldom used in their pure form. Various filler particles, either intrinsically present during the processing of polymer mixtures or added deliberately, change their macroscopic (e.g. mechanical) properties, and also affect the phase separation of polymer blends. Phase separation can in turn affects the morphology and stability.

effect of filler geometry

Wall (surface directed)
Rods (interference)
Particle array (interference)
Other geometry
diamond:
fractal cluster:

confinement

(click on figure to view movie of pattern evolution)

narrow gap with very low surface energy (h=0.001)

Average profile (none)
narrow gap with low surface energy (h=.05)

Average profile
narrow gap with medium surface energy (h=1)

Average profile
narrow gap with strong surface energy (h=5)

Average profile
wide gap with low surface energy (h=0.05)

Average profile
wide gap with medium surface energy (h=1)

Average profile
wide gap with strong surface energy (h=1)

Average profile

The study of the effects of inclusions on the phase separation and mesoscopic structure of polymer thin films may shed some light onto similar problems in lipid membranes. I am also interested in the role of polymers in biophysics, including micelle formation, the controlled release of drugs through porous polymers, and the binding of ligands to biopolymers.