Two soluble fluorescent polymers, poly(2-decyloxy-5-(4 0tert-butylphenyl)-1,4-phenylenevinylene) (DtBP-PPV) and poly(2-decyloxy-1,4-phenylenevinylene) (DO-PPV), were prepared by a method similar to the Gilch procedure. The DtBP-PPV and DO-PPV have a same chemical structure except for the conjugated tert-bytulphenyl substituents in the former. The polymers are characterized by using 1 H NMR, FTIR, UV-vis, photoluminescence (PL), and electroluminescence (EL) spectroscopies and thermogravimetric analysis (TGA). The 1 H NMR spectra show no tolane-bis-benzyl (TBB) structure defects in DtBP-PPV but some in DO-PPV. Both UV-vis absorption and PL emission peaks of the DtBP-PPV exhibit a red-shift phenomenon as compared with those of the DO-PPV. Moreover, with the DtBP-PPV and DO-PPV acting as light-emitting polymers separately, EL devices were fabricated with a sequential lamination of ITO/PEDOT/DtBP-PPV (or DO-PPV)/ Ca/Ag. The DtBP-PPV-based device shows a lower turnon voltage, a longer EL emission wavelength, and a higher brightness than the DO-PPV-based device. The maximum brightness of DtBP-PPV-based device is 57 cd/ m 2 at an applied voltage of 12 V.

No abstract

Styrene miniemulsion polymerizations stabilized by sodium lauryl sulfate in combination with a reactive costabilizer, lauryl methacrylate (LMA) or stearyl methacrylate (SMA), were studied. A small amount of extremely hydrophobic dye was incorporated into monomer droplets (102 nm in diameter) to investigate particle nucleation and growth mechanisms. In addition to monomer droplet nucleation, particle nuclei generated in the aqueous phase (homogeneous nucleation) also play an important role in both LMA‐ and SMA‐containing polymerization systems. The way that these two nucleation mechanisms compete with each other is closely related to the water solubility of the costabilizer (LMA > SMA). The fraction of latex particles originating from homogeneous nucleation increases with decreasing hydrophobicity of the costabilizer. Zeta potential data of latex particles and the molecular weight and molecular weight distribution of emulsion polymers provide supporting evidence for the proposed competitive particle nucleation and growth mechanisms. © 2002 Society of Chemical Industry

A new soluble luminescent poly[2-decyloxy-5-(2 0 ,5 0 -bis(decyloxy)phenyl)-1,4-phenylenevinylene] (DBDP-PPV) is prepared by the dehydrohalogenation of 1,4-bis (bromomethyl)-2-decyloxy-5-(2 0 ,5 0 -bis(decyloxy)phenyl) benzene (as monomer) in this study. The above monomer bearing decyloxy and 2 0 ,5 0 -bis(decyloxy)phenyl substituents was prepared via such chemical reactions as alkylation, bromination, and Suzuki coupling reactions. The two asymmetric substituents on the phenylene ring make the DBDP-PPV soluble in organic solvents and eliminate the tolan-bisbenzyl (TBB) structure defects. The structure and properties of the DBDP-PPV are examined by 1 H-NMR, FT-IR, UV=Vis, TGA, photoluminescence (PL), and electroluminescence (EL) analyses. The DBDP-PPV film exhibits a PL peak at 519 nm. With the DBDP-PPV acting as a light-emitting polymer, a device is fabricated with a sequential lamination of ITO=PEDOT=DBDP-PPV=Ca=Ag. The EL spectrum of the device shows a maximum emission at 507 nm. The turn on voltage of the device is about 15.6 V. Its maximum brightness is 4.67 cd=m 2 at a voltage of 16.8 V.

ABSTRACT:The synthesis of potential fluorescent active 4-(5-aryl-1,3,4-oxadiazol-2-yl)