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P. N. Prasad, N. Deepak Kumar, Manjari Lal, Mukesh P. Joshi Photonics Research Laboratory, Department of Chemistry State University of New York At Buffalo Buffalo, NY 14260-3000

Abstract Nanoscale synthesis and processing provides a novel approach for making a new generation of nanocomposite materials with exceptional optical and electrical properties that are needed for the development of new technologies. This presentation will focus on the preparation of nanocomposites made of Poly (para-phenylene vinylene) (PPV) with other polymers, inorganic glasses and semiconductors. We will present a new approach of nanoscale polymerization for making processable monodispersed oligomeric species of PPV which uses the base catalyzed polymerization of PPV monomer within the cavity of a reverse micelle nanoreactor. Application of this approach of fabricating novel materials for a variety of applications in photonics will also be discussed. In addition, we will discuss fabrication of bulk nanocomposites of PPV and silica by in-

situ polymerization of monomer within a porous glass and their lasing properties.

INTRODUCTION Multifunctional polymers that simultaneously exhibit more than one property are a new generation of materials which hold considerable promise for numerous applications in the field of electronics and photonics. Polymer light emitting diodes, polymer lasers and photorefractive polymers are some significant examples [1-3]. Nanosize manipulation of molecular architecture

and their morphology provides a powerful approach to control electronic and optical properties of a material as well as its processability. This is why the design and processing of nanostructured materials has emerged as a frontier area of materials research. Poly(p-phenylene vinylene) is a promising n-conjugated polymer for applications in photonics due to its large non-resonant optical nonlinearity. The large photoluminescence quantum efficiency of PPV and the discovery of electroluminescence in PPV and its derivatives generated a great deal of interest in this class of materials. Recently, researchers have demonstrated optical amplification in PPV and its analogs in solution and in pure thin film when excited with an appropriate light source.

227 Mat. Res. Soc. Symp. Proc. Vol. 488 0 1998 Materials Research Society

In this paper we present novel approach for synthesis and processing of nanosized oligomeric species of PPV through reverse micelle technique as well as the fabrication of nanocomposites of PPV with other polymeric systems, inorganic glasses and semiconductors. Applications of nanocomposites in polymer lasing and elecroluminescence are also discussed.

NANOSCALE OLIGOMERIC PPV VIA REVERSE MICELLE TECHNIQUE 1. Synthesis Reverse micellar solutions were prepared by dissolving appropriate amounts of sodium bis(2-ethylhexyl)sulfosuccinate(AOT, a surfactant) in isooctane (2,2,4 trimethylpentane) and adding specific volumes of aqueous solution of the base (NaOH) to achieve the desired Wo value. The Wo value, defined as polar fluid-to