Hybridization of Emitting Polyfluorene with Silicone Shinji Nishikawa, 1 Sayaka Kami, 1 Nurul Ashikin, 2 Badrul Haswan, 2 Takahiro Uno, 1 Takahito Itoh, 1 Masataka Kubo 3 1 Division of Chemistry for Materials, Graduate School of Engineering, Mie University, Tsu 514-8507, Japan 2 Faculty of Chemical Engineering Technology, TATI University College, 24000 Kemaman, Terengganu, Malaysia 3 Division of Advanced Integration Engineering, Graduate School of Regional Innovation Studies, Mie University, Tsu-514-8507, Japan Correspondence to: M. Kubo (E - mail: kubo@chem.mie-u.ac.jp) Received 3 July 2014; accepted 27 November 2014; published online 22 December 2014 DOI: 10.1002/pola.27493 ABSTRACT: Polyfluorenes with pendant allyl groups were pre- pared by terpolymerization of 9,9-dihexylfluorene-2,7-bis(trime- thyleneborate), 2,7-dibromo-9,9-bis(2-allyloxyethyl)fluorene, and 4,7-dibromo-2,1,3-benzothiazole, or 4,7-dibromo-2,1,3- naphthoselenadiazole using Suzuki coupling reaction. The sub- sequent hydrosilylation reaction of these precursor polymers with ethoxydimethylsilane quantitatively converted the allyl groups to ethoxysilyl groups. Hybridization of the emitting pol- yfluorenes with silicone was successfully achieved by the solvent-free sol–gel reaction of tetraethoxysilane and silanol- terminated polydimethylsiloxane in the presence of the ethoxysilyl-functionalized polyfluorenes. Fluorescence spectra of these luminescent silicones revealed that emitting polyfluor- enes were dispersed homogeneously in the matrix of silicone without aggregation. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 622–628 KEYWORDS: composites; conjugated polymers; networks; silicones INTRODUCTION Over the past decades, great efforts have been made to develop new p-conjugated polymers because of their potential applications for electrical conductors, organic light-emitting diodes, solar cells, field effect transis- tors, charge storage devices, biosensors, and actuators. 1–4 Conjugated polymers are a unique class of materials not only for optical applications but also for electrical applica- tions. We are interested in incorporation of p-conjugated polymers into inorganic materials to develop a new compos- ite material for various applications. We have reported organic/inorganic hybrids composed of p-conjugated poly- mers and silica as an organic and inorganic segments, respectively. 5–7 Hydrolysis-condensation of alkoxysilane (sol– gel process) in the presence of p-conjugated polymer with functionalities that can interact with silica gave homogene- ous hybrid retaining the properties of p-conjugated polymer embedded in the silica. As part of our efforts to exploit a new series of hybrid mate- rial based on p-conjugated polymers, the aim of the present work is to incorporate emitting polyfluorene copolymers into silicone. Silicones have been widely used in various fields due to their elastic behavior, good thermal stability, low sur- face energy, and bio-compatibility. 8,9 Recently, silicones have attracted considerable attention from light emitting diode (LED) manufacturers for use as encapsulants and lenses. Especially, yellow phosphor filled silicones are important materials for white light LED. Since inorganic phosphor par- ticles tend to settle out, one of the technical challenges is to ensure uniform mixing and dispersion of the binder and phosphor. Our idea is to hybridize emitting polymer with sili- cone to obtain a transparent luminescent material based on silicone. To the best our knowledge, there are only a few reports of hybrid material composed of emitting polymer and silicone in the literature. Atvars and Coworkers reported hydrosilylation reaction of vinyl-functionalized polyfluorene with poly(dimethylsiloxane-co-methylsiloxane) to observe the polyfluorene morphology embedded in silicone. 10 Since poly- fluorene and silicone don’t mix each other, our strategy for homogeneous mixing is grafting of polydimethylsiloxane (PDMS) chains onto polyfluorenes followed by crosslinking of the introduced PDMS chains. The sol–gel reaction of tet- raethoxysilane (TEOS) and silanol-terminated polydimethylsi- loxane (HO-PDMS-OH) in the presence of ethoxysilyl- functionalized polyfluorene will give a polyfluorene/silicone hybrid in which the emitting polyfluorene is homogeneously immobilized in the silicone matrix (Scheme 1). In this study, we will report the preparation of polyfluorenes with pendant ethoxysilyl groups and its hybridization with silicone utiliz- ing sol–gel technique. V C 2014 Wiley Periodicals, Inc. 622 JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2015, 53, 622–628 ARTICLE WWW.POLYMERCHEMISTRY.ORG JOURNAL OF POLYMER SCIENCE