Science at the nanoscale has been one of the most exciting areas of recent investigation, with activities that are of both fundamental and technological significance. New physical phenomena and revolutionary nanoeletronic devices based on novel nanomaterials are anticipated. Organic conjugated systems have been successfully applied to electronics because of their versatile electronic properties and their adaptability to a broad range of processing methods. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] However, the development of polymer electronics at the nanoscale is in its infancy.Here we report the first synthesis of polythiophene nanoneedles that exhibit fast, field-induced conductance switching in a single nanocrystalline element.Most of the bulk conducting-polymer systems studied contain regions that are inhomogeneous. The investigation of processes in a nanodomain of a single crystal is critical in ascertaining the inherent electronic properties of polymer nanoelements. Single nanocrystals of conducting polymers have not been reported, although needle-shaped bulk crystals of the quarterphenyl cation radical salt have previously been studied, [15,16] and highly ordered polymer structures have been prepared by methods including electrochemical epitaxial polymerization, [10] solution spin-coating on functionalized surfaces, [17] and solid-state polymerization of monomer crystals. [18] To date, polythiophenes, together with polyanilines and polypyrroles, represent the most important classes of conducting polymers. [19] Applying an interfacial polymerizationcrystallization process, we have prepared single crystals of poly(3,4-ethylenedioxythiophene) (PEDOT) as nanoneedles.The aqueous/organic interface used consists of 3,4-ethylenedioxythiophene (EDOT) in an organic solvent and an oxidant, ferric chloride, in deionized (DI) water. The use of ferric chloride as an oxidant in the precipitation polymerization of thiophenes has been documented. [20][21][22] In these reactions, polymer chains are generally formed first, followed by the precipitation of crystals. Our system uses, for the first time, ferric chloride in the interfacial polymerization of thiophenes.As the crystal growth is simultaneous with polymerization, more ordered crystal packing can be expected. In a typical synthesis, EDOT dissolved in dichloromethane (DCM, 5 mL, 1 mg mL -1 ) served as the lower organic layer, and FeCl 3 dissolved in DI water (5 mL, 1 mg mL -1 ) formed the upper layer. After 2 days, the aqueous layer was carefully collected for purification. To prevent the hydrolysis of FeCl 3 , 5 drops of concentrated HCl (37 %) were added to the collected suspension. The nanoneedle suspension was then centrifuged, and the precipitate was re-suspended. This process was repeated twice and was followed by a final dialysis step in ultrapure water (resistivity 18.2 MX cm, total organic carbon level 10 ppb) for 10 h. The oxidative coupling polymerization of EDOT at the aqueous/organic interface was facilitated by FeCl 3 [23] and is an example of a s...

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Silylene- and siloxane-functional conjugated polymers and macrocycles could be synthesized via acyclic diene metathesis (ADMET) condensation of silylene- and siloxane-containing bis-styryl monomers. The organic conjugated segment formed was stilbene with all-trans-configured vinylene bonds. The flexible siloxane linkage resulted exclusively in dimeric macrocycles under the reaction conditions investigated, while the silylene linkage led to linear polycondensates with molecular weights M n ∼2000−6000 g/mol as determined by GPC and molecular weight distributions M w/M n ∼ 1.4−1.7. The microstructure was proven by means of 13C NMR, 1H NMR, 29Si NMR, and FTIR. Photophysical characterization of the products showed the participation of Si in the conjugation, in both the siloxanes and silylenes, with photoluminescence quantum efficiencies ∼24−28% and blue light emission.