Accomplishments in the second year:

1
Photopolymerization Induced Phase Transition and
Evolution of Morphology Landscape in Holographic
Polymer Dispersed Liquid Crystals and Photonic
Crystals Thein Kyu, University of Akron, DMR
0514942

• Objectives
• Fabricate photonic crystals based on wave
  interference holographic photolithography
• Elucidate mechanisms of photopolymerization
  induced crystallization or liquid crystal ordering

Unusual Discovery During the holographic
photo-patterning of various conductive crystals
and liquid crystals, we stumbled on a very
interesting phenomenon of induced smectic phase
from a hyperbranched polyester/nematic LC mixture
both of which have no known smectic phase in
their neat forms. The present work is the first
to find an induced smectic phase in an amorphous
hyperbranched system where there is no mesogenic
group in the hyperbranched molecule. It is an
outcome of our international collaboration with
Professor T. Nishikubo of Kanagawa University.

• Accomplishments in the second year
• Developed a phase field theory of
  photopolymerization induced crystallization in a
  blend of crystalline polymer and photo-curable
  monomer.
• Applied this phase field theory to directional
  crystal growth in reactive polymer mixtures
  driven by photo-intensity gradient.
• Fabricated various photonic crystals using wave
  interference holographic lithography.
• Discovered an induced smectic phase in a nematic
  mixture containing a non-mesogenic functional
  hyperbranched polyester.

2
Photopolymerization Induced Phase Transition and
Evolution of Morphology Landscape in Holographic
Polymer Dispersed Liquid Crystals and Photonic
Crystals Thein Kyu, University of Akron, DMR
0514942
Broader Impact
Collaborations Our recent international
collaboration has resulted in a new discovery on
induced smectic phase in mixtures of nematic
liquid crystal and non-mesogenic hyperbranched
(HB) polyester (In collaboration with T.
Nishikubos group of Kanagawa University, Japan).
This induced smectic phase has striking
similarity to that found in a binary nematic
system by the PIs group about a decade ago and
is also similar to the work in progress in
collaboration with Dean Shila Gargs group at
Wooster College. Exchange of student and faculty
visits is expected in coming years.
Education Outreach A REU student, Garret
O'Malley, a sophomore student from Physics
Department, Bucknell University, PA, is receiving
research training in the PIs group. He has
established a phase diagram of azobenzene/triacryl
ate system and subsequently performed wave
interference holographic photolithography to
fabricate photonic crystals. In addition, he is
learning the computer codes for determining the
coexistence lines of liquid-liquid and
solid-liquid phase transitions. The PI gave a
lecture on Rhythms in Solidification of Soft
matter An Interdisciplinary Research to a group
of NSF-REU Summer students.

Students Involved Mr. P. Dayal graduated in May
2007, with a Ph. D. dissertation on Modeling of
electro-jet spinning of crystal-liquid crystal
blends . He is now working as a post-doctoral
research fellow under Professor A. Balazs at
University of Pittsburgh. Mr. R. A. Matkar
graduated in August 2007 with a thesis entitled
Phase diagram and dynamics of solid-liquid phase
transitions of binary crystalline polymer
blends, is now working as a postdoctoral fellow
under Prof. M. Chowdury at Lehigh University.
Mr. P. Rathi (Ph. D. Candidate, theory and
simulation polymerization induced phase
transitions) and Ms. S. Park, (Ph. D. Candidate,
experimental phase diagrams and
photopolymerization induced phase transitions)
are expected to graduate within 6 to 9 months.
Mr. N. Kim, who discovers an induced smectic-A
phase in E7/HBPEAc-COOH mixtures, is a Ph. D.
candidate working on photo-patterning of advanced
materials. Mr. T. Hwang, a Ph. D. candidate is
hired recently under the present grant to develop
holographic glucose sensors for noninvasive
detection in collaboration with Professor Jun Hu,
Department of Chemistry at University of Akron.