No abstract

We have synthesized, using the Gilch polymerization method, a new series of high-brightness, soluble copolymers (POSS-PPV-co-MEHPPV) of poly(p-phenylenevinylene) (PPV) containing side-chain-tethered polyhedral oligomeric silsesquioxane (POSS) pendent units and poly(2-methoxy-5-[2-ethylhexyloxy]-1,4-phenylenevinylene) (MEHPPV). This particular molecular architecture of POSS-PPV-co-MEHPPV copolymers possesses not only a larger quantum yield (0.85 vs 0.19) but also higher degradation and glass transition temperatures relative to those of pure MEHPPV. The maximum brightness of a double-layered-configured light-emitting diode (ITO/PEDOT/emissive polymer/Ca/Al) incorporating a copolymer of MEHPPV and 10 mol % PPV-POSS was 5 times as large as that of a similar light-emitting diode incorporating pure MEHPPV (2196 vs 473 cd/m2).

We report a method for fabricating ordered spatial arrangements of pre-synthesized CdS nanoparticles in thin block copolymer templates by first selectively dispersing these nanoparticles in one particular block of a diblock copolymer, in bulk, by means of dipole–dipole interactions and then using solvent selectivity to sequester CdS nanoparticles in the block copolymer thin film. A long-range, ordered morphology of CdS nanoclusters can be obtained by using patterned substrates with 400 nm shallow grooves. The incorporated nanoparticles retain the same luminescence characteristics as in the pure state.

Summary: Polystyrene‐block‐poly(ethylene oxide) (SEO) block copolymer thin films, in which CdS clusters have been sequestered into the PEO domains of the SEO block copolymers, are found to induce the morphological transformation of PEO from cylinders to spheres, as shown by using atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). This transformation is caused by the presence of hydrogen‐bonding interactions between surface‐hydroxylated CdS and PEO, as confirmed by nuclear magnetic resonance (NMR) studies.Morphological transformation of PEO cylinders into CdS/PEO spheres by hydrogen‐bonding interactions between surface‐hydroxylated CdS and PEO.imageMorphological transformation of PEO cylinders into CdS/PEO spheres by hydrogen‐bonding interactions between surface‐hydroxylated CdS and PEO.

Self‐assembled and aligned in a block! Self‐assembled CdSe nanorods within the poly(4‐vinylpyridine) nanodomains of a poly(styrene‐b‐4‐vinylpyridine) diblock copolymer thin film can be aligned under the influence of the polarization forces created by an applied electric field. The electron mobilities of the CdSe/poly(4‐vinylpyridine) nanodomains in the out‐of‐plane cases were about eight times larger than those in the in‐plane cases.