# Presentation: 728172

## Accomplishments in the first year:

**Figure 2.**** ****Directional crystal growth of polyethylene oxide (PEO) upon exposure to truncated intensity profile created the Iris diaphragm showing the spherulitic growth near the core and seaweed growth from the outer peripheral edge. Photopolymerization of 30/70 PEO/DA blend was undertaken in the melt at 52****o****C. The photo-initiator utilized was Rose Bengal at 1wt% of DA under green-filtered light illuminated at an intensity of 0.017 mW/cm****2****. **

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**Accomplishments in the first year:**
**Established a new concept of photopolymerization induced crystallization in a blend of crystalline polymer and photo-curable monomer.**
**Introduced and proved a novel approach of directional crystal growth in reactive polymer mixtures driven by photo-intensity gradient. **
**Developed a new theory of solid-liquid phase transition of polymers involving mesophase ordering and crystallization that is capable of accounting for eutectic, peritectic and azeotropic phase diagrams involving various coexistence regions bound by the solidus and liquidus lines.**

**Figure 1.**** ****Theoretical snap shots of enhancement of UCST as a function of conversion in comparison with melting points of PEO/DA before and after curing.**

**Objectives:**
**Develop gradient structures in conductive organic crystals and liquid crystals for photonic applications**
**Elucidate mechanisms of photopolymerization induced crystallization**

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

## Broader Impact: The directional crystal growth in reactive polymer mixtures driven by photo-intensity gradient is conceptually similar to the directional solidification in metal alloys. The pattern forming aspects of mesophase structures in soft matters share a common ground with phase transitions and solidifications of small molecule systems such as organic crystals, metal alloys, and biological substances.

**Education Outreach: ****The PI and his former post-doctoral fellow, Dr. Scott Meng, have developed a time-resolved light scattering device capable of performing remote controlled experiment. The Web based remote controlled experimentation is particular useful for the present photopolymerization project as the students do not have to stay in the dark room during the experiments.**

**Students Involved:** **Mr.** **P. Dayal (Ph. D. Candidate, phase diagrams of crystal-liquid crystal blends and modeling of electro-jet spinning), Mr. R. Matkar (Ph. D. Candidate, phase diagram of binary crystalline polymer blends and dynamics of solid-liquid phase transitions), Mr. P. Rathi (Ph. D. Candidate, theory and simulation polymerization induced phase transitions), Ms. S. Park, (Ph. D. Candidate, experimental phase diagrams and photopolymerization induced phase transitions). Mr. Dayal and Matkar are expected to graduate in Summer, 2006. Two new students Mr. N. Kim, (phase diagrams of liquid crystals and mesogenic reactive LC monomers and photopolymerization induced mesophase transition) and Mr. C. Neelakandan, (development of asymmetric membranes for biomedical applications) have been already hired with the Departmental support****. Dr. S. De a post-doctoral fellow is working on the coarse grain modeling based on the vector order parameter to decipher the intricate mesomorphic polymer crystals.**** **

**Collaboration: ****PI has been collaborating with Professor Dmitry Golovaty of the Department of Applied Mathematics, UA**. **He is currently collaborating with Chuck Parsons of the Akron Global Polymer Academy for the development of remote experimentation.**