CAREER: Living Ring-Opening Polymerization: A New Route to Emissive Materials

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9500627 Bazan The aim of this proposal is to take advantage of our recently developed paracyclophan-1-ene based PPV-poly(para phenylenevinylene) methodology to resolve issues of technical importance. Emphasis will be placed on new macromolecular approaches that improve the environmental stability of conjugated polymers while maintaining photo optical features of interest. We are also interested in investigating stereoregularity issues on polychromophores, their influence on secondary structure and, ultimately, bulk properties. During the grant period, specific aims are: (1) To expand the scope of our mild and living polymerization route to defect-free PPV so that electronpoor versions of PPV can be prepared in this way. (2) To study, by use of molecular modeling, how the secondary structure in poly(paracyclophan-1-ene)s enforces chromophore aggregation. (3) To investigate whether photogenerated acids are capable of catalyzing a solid state dehydration reaction to form PPV so as to permit patterning using microlithographic processes. (4) To examine the effect of chain length and degree of aggregation on the emission quantum yield and durability of PPV prepared via our new route, in the hope of optimizing these properties. (5) To begin an investigation into the microheterogeneous properties of block copolymers containing PPV fragments. (6) To characterize, using standard solution methods, the ability of PPV chains to form excited state dimers (excimers) with both donor and acceptor molecules. %%% Conducting polymers are reaching maturity as a scientific field. Fundamental advances in synthetic methodology, primarily brought about by chemists, have permitted their use by physicists and engineers as components in electronic and electro-optic devices such as light emitting diodes, electrophotographic photoreceptors, solar energy conversion systems, polymer based capacitors and photodetectors. The interest in applying polymers to these functional de vices stems from their superior processability and low density, relative to inorganic materials, as well as their intrinsic amorphous nature. However, the structural and bonding features that lead to a small band gap not only reduce significantly the solubility and processability of the material but inevitably make chemical oxidation of this class of materials facile. This reactivity places severe limits on their environmental stability and general longterm durability. Successful implementation of these molecular- based electronic and electro-active devices will therefore depend to a large extent on our ability to design and synthesize a new generation of conjugated polymers that are environmentally stable. During this grant period, the junior-level advanced inorganic/organic methods and instrumentation course will continue to be innovated to include for the first time x-ray structure determination. This course will combine rigorous chemical manipulations with an introduction to stae-of-the art instrumentation. Funds for the purchase of computer equipment have already been raised. ***