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(b). (a). EO molecules. Lamella. Cylinder. Sphere. 300 nm. 300 nm. (c). (d). 100 nm. 100 nm. Nanostructural Control of Optical Properties in Polymers with Electroactive Subunits Padma Gopalan, University of Wisconsin-Madison, DMR 0449688.

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  1. (b) (a) EO molecules Lamella Cylinder Sphere 300 nm 300 nm (c) (d) 100 nm 100 nm Nanostructural Control of Optical Properties in Polymers with Electroactive SubunitsPadma Gopalan, University of Wisconsin-Madison, DMR 0449688 Electro-optic (EO) materials are commonly designed as a guest-host composite. In this research we focus onmaximizing the EO activity for a given chromophore by controlling the nanomorphology. Block copolymer templates are used to systematically control the size and shape of chromophore domains and study its correlation to EO coefficient. We have utilized a block copolymer template to successfully encapsulate a thiophene based EO chromophore (ChrT) in spherical, cylindrical and lamellar domains. The domain size was controlled between 20 to 50 nm. Optical characterization of the composites indicate that in addition to the domain size the spacing between the chromophores within the domains is critical to maximizing the EO activity. Figure 1. TEM images of block copolymer encapsulated with EO chromophores with weight fraction of 0.38 (a), 0.28 (b), 0.20 (c), and 0.12 (d), which results in lamellar, a transition between lamellar and cylindrical, cylindrical and cylindrical morphology respectively.

  2. Nanostructural Control of Optical Properties in Polymers with Electroactive SubunitsPadma Gopalan, University of Wisconsin-Madison, DMR 0449688 Education Under this grant, two graduate student Melvina Leolukman and Peerasak Paoprasert are pursuing their Ph.D. degree. This project has provided an ideal platform for the students to gain expertise in SEM, TEM, X-ray diffraction (Argonne National Lab), electro-optic measurement methods. A chemistry undergraduate Ian Mandal has been working on synthetic aspect of the project. • Outreach • We have continued to work closely with Prof. McGee to involve undergraduate students both at Drew University and at UW-Madison, to successfully set up the electrical poling and bench top EO coefficient measurement apparatus at UW-Madison. • Hosted REU student Kimy Yueng for research on chromophore synthesis. Figure 2: Graduate student Peerasak with Drew undergraduate Elizabeth working on the optics set up in the PI’s lab. Figure 3: REU student Kimy Yueng (left) with graduate student Melvina at the poster presentation for UW-Madison, REU Program in summer 2007.

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