Get turned on: Fluorescent photochromic organic nanoparticles (FPONs) of 1 (see picture) show a strongly enhanced fluorescence emission with increasing concentration and bistable photochromism. High‐contrast on/off fluorescence switching has been successfully implemented in size‐tuned FPONs of 1 and also in a photo‐rewritable polymer film highly loaded with 1.

We report on the investigations of electroluminescence (EL) for the polymer blend composed of two organic soluble polymers. The blends consist of main chain conjugated poly [(2-methoxy-5-((2ethylhexyl)oxy)-1,4-phenylene)vinylene] (MEH-PPV) and a side chain luminescent polymer, an alkoxy-(trifluoromethyl)stilbene-substituted PMA derivative (CF3-PMA). Emitting colors of the polymer blends varied with the blending ratios of two polymers. The electroluminescent peak of the MEH-PPV-rich polymer blend ranged over 580-800 nm (orange-red light), and of the CF3-PMA-rich polymer blend ranged from 380 to 800 nm, resulting in a white-light emission. Additional new EL peaks of polymer blends at around 380 and 800 nm would originate from the CF3-PMA and the exciplex formed by photoinduced electron transfer between two polymers.

Mehr hilft mehr: Fluoreszierende photochrome organische Nanopartikel (FPONs) aus 1 (siehe Bild) zeigen eine mit zunehmender Konzentration stark ansteigende Fluoreszenzemission sowie eine bistabile Photochromie. Ein kontrastreiches Ein/Aus‐Schalten der Fluoreszenz wurde in größenabgestimmten FPONs aus 1 und in einem wiederbeschreibbaren Polymerfilm mit hoher Beladung an 1 verwirklicht.

We describe photopatterning technique that employs the photodegradation of cell-adhesive-modified poly(ethyleneimine) (m-PEI) to fabricate precise micropatterns on the indium tin oxide (ITO) substrate for guided neuronal growth. The photodegradation of m-PEI coated on hydroxyl group-terminated ITO substrate created micropatterns over a large area through deep UV irradiation. The photopatterned m-PEI layer can effectively guide neurite outgrowth and control neurite extensions from individual neurons.

Aiming at the realization of high-performance polymeric electroluminescence (EL) devices, various kinds of poly(pphenylenevinylene) derivatives (PPVs) have been synthesized and investigated with emphasis on their processability, color tunability, and stability. [1][2][3][4] To improve a poor processability of the original PPV, incorporation of solubilizing functional groups or the use of precursor routes has been extensively employed for EL application. 2,3 As an alternative approach, dendritically structured PPVs are gaining significant attention, very recently, due to their excellent solubility, film quality, and improved luminescence efficiency. [5][6][7][8] It is well-known that the dendritic molecules, i.e., dendrimers and hyperbranched polymers, are provided with the favorably reduced intramolecular and intermolecular interactions due to their characteristic branch structures, which in turn render them more soluble and highly fluorescent in the solid state. [9][10][11][12] It must be critically noted, however, that all the dendritic PPVs reported so far 5-8 comprise 1,3,5-connectivity (two meta-linkages) in the branch units which strictly restricts the extension of π-conjugation length within the branch points (see the π-conjugation resonance structure of 1,3,5-dendritic PPV in Figure 1). Because of this limited π-conjugation, the optical properties of the 1,3,5-dendritic PPV must be independent of their molecular weights (vide infra for the data). However, increased π-conjugation length with growing molecular weight is a fundamental property of the conjugated PPVs. In this communication, we demonstrate a modified strategy for obtaining a proper dendritic PPV which shows increasing π-conjugation length with growing molecular weight. To this end, we employed a simple but novel strategy of adopting 1,2,4-linking (ortho-and para-connecting) AB 2 monomer for the dendritically conjugated PPV synthesis because 1,4connectivity as well as 1,2-connectivity (lesser extent) contributes to the extension of π-conjugation lengths (see the structure in Figure 1).Two different types of AB 2 monomers, 4-bromo-1,3-divinylbenzene and 5-bromo-1,3-divinylbenzene, for obtaining 1,2,4-dendritic PPV and 1,3,5-dendritic PPV (as the control sample), respectively, were synthesized according to the reaction routes shown in Scheme 1, and their structures were fully characterized by 1 H NMR, 13 C NMR, FT-IR, and mass spectroscopy analysis (see Supporting Information for the synthesis and structural identification data).