Controlling Ionomer Morphologies Karen I. Winey, University of Pennsylvania, DMR- 0235106

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Controlling Ionomer MorphologiesKaren I. Winey,
University of Pennsylvania, DMR- 0235106
To date, the sizes of the nano-scale ionic
aggregates present in ionomers as determined by
scanning transmission electron microscopy (STEM)
experiments are inconsistent with small angle
x-ray scattering (SAXS) data interpreted by the
Yarusso-Cooper model. To address this
discrepancy we have investigated a pair of model
gold nanoparticles with both STEM and SAXS. For
STEM these nanoparticles were supported by
amorphous PS films and the optimal specimen
thickness was determined to be less than 50 nm.
SAXS was performed on dilute solutions of the
nanoparticles and fit using a model of
monodisperse, non-interacting hard-spheres.
Analysis of this model nanoparticles has allowed
us to optimize several experimental conditions as
we move toward reconciling STEM and SAXS data
from ionomers.
DSAXS DSTEM
Au 11 1.4 nm 1.3 nm 0.14
Au 55 1.7 nm 1.7 nm 0.25
Dilute Monodisperse Hard-sphere model 3000k magnification 20 nm PS Gaussian FWHM
STEM and SAXS data have been reconciled for a
model system of high Z nanoparticles
For a combined system of Au 11 and Au 55, STEM
data suggests a bi-modal distribution of particle
sizes while SAXS data indicates hard-spheres with
diameter of 1.6 nm.
Benetatos, et al. Macromolecules, in press.
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Controlling Ionomer MorphologiesKaren I. Winey,
University of Pennsylvania, DMR-0235106
Public Lecture Prof. Winey gave a public
lecture at York College in York, PA as part of a
year long series. The audience included high
school groups, engineers working in the area, and
York College students, faculty and
administrators. In addition, a collection of
young girls (10-13 years old) attended motivated
by the opportunity to see a woman
scientist. Outreach to Industry Prof. Winey has
arranged to spend her scholarly leave at Dupont
Experimental Station in Wilmington, DE during the
Fall 2005 semester. This will enable the
extension of our morphological studies to
industrial applications including fluorinated
ion-containing polymers.