Organic semiconductors that can be fabricated by simple processing techniques and possess excellent electrical performance, are key requirements in the progress of organic electronics. Both high semiconductor charge-carrier mobility, optimized through understanding and control of the semiconductor microstructure, and stability of the semiconductor to ambient electrochemical oxidative processes are required. We report on new semiconducting liquid-crystalline thieno[3,2-b ]thiophene polymers, the enhancement in charge-carrier mobility achieved through highly organized morphology from processing in the mesophase, and the effects of exposure to both ambient and low-humidity air on the performance of transistor devices. Relatively large crystalline domain sizes on the length scale of lithographically accessible channel lengths (∼200 nm) were exhibited in thin films, thus offering the potential for fabrication of single-crystal polymer transistors. Good transistor stability under static storage and operation in a low-humidity air environment was demonstrated, with charge-carrier field-effect mobilities of 0.2–0.6 cm2 V−1 s−1 achieved under nitrogen.

Liquid-crystalline semiconducting polymers with high charge-carrier mobility.

The cost-effective production of flexible electronic components will profit considerably from the development of solution-processable, organic semiconductor materials. Particular attention is focused on soluble semiconductors for organic field-effect transistors (OFETs). The hitherto differentiation between "small molecules" and polymeric materials no longer plays a role, rather more the ability to process materials from solution to homogeneous semiconducting films with optimal electronic properties (high charge-carrier mobility, low threshold voltage, high on/off ratio) is pivotal. Key classes of materials for this purpose are soluble oligoacenes, soluble oligo- and polythiophenes and their respective copolymers, and oligo- and polytriarylamines. In this context, micro- or nanocrystalline materials have the general advantage of somewhat higher charge-carrier mobilities, which, however, could be offset in the case of amorphous, glassy materials by simpler and more reproducible processing.

Organic semiconductors for solution-processable field-effect transistors (OFETs).

The present invention is directed to compositions (“Nanomaterial Polymer Compositions”) comprising a silicone polymer and a nanomaterial, including but not limited to, a single or multi-walled nanotube, a nanowire, a nanodot, a quantum dot, a nanorod, a nanocrystal, a nanotetrapod, a nanotripod, a nanobipod, a nanoparticle, a nanosaw, a nanospring, a nanoribbon, a branched nanomaterial, or any combination thereof. The Nanomaterial Polymer Compositions are useful for optical and sensing devices including but not limited to noise suppression, passive Q-switching, mode-locking, waveform shaping, optical switching, optical signal regeneration, phase conjugation or filter devices, dispersion compensation, wavelength conversion, a soliton stabilization, microcavity applications, interferometers; optical, magneto-optical or electro-optical modulation; and biochemical sensors and photodetectors. The Nanomaterial Polymer Compositions are also useful in soft lithography processes.

Nanomaterial polymer compositions and uses thereof

Durability of nanosized oxygen-barrier coatings on polymers

Nanoscale composites have been a technological dream for many years. Recently, increased interest has arisen in using carbon nanotubes as a filler for polymer composites, owing to their very small diameters on the order of 1 nm, very high aspect ratios of 1000 or more, and exceptional strength with Young’s modulus of approximately 1 TPa. A key issue for realizing these composites is obtaining good interfacial adhesion between the phases. In this work, we used force-field based molecular mechanics calculations to determine binding energies and sliding frictional stresses between pristine carbon nanotubes and a range of polymer substrates, in an effort to understand the factors governing interfacial adhesion. The particular polymers studied were chosen to correspond to reported composites in the literature. We also examined polymer morphologies by performing energy-minimizations in a vacuum. Hydrogen bond interactions with the ∏-bond network of pristine carbon nanotubes were found to bond most strongly to the surface, in the absence of chemically altered nanotubes. Surprisingly, we found that binding energies and frictional forces play only a minor role in determining the strength of the interface, but that helical polymer conformations are essential.

Molecular mechanics of binding in carbon-nanotube–polymer composites

Polyethers having improved barrier to oxygen are normally solid, thermoplastic polyethers having aromatic ether repeating units in their backbones and pendent hydroxyl moieties and pendent amido, N-substituted amido and/or hydroxyalkyl moieties. Such polyethers are prepared by reacting diglycidyl ethers of dihydric aromatic compounds such as the diglycidyl ether of bisphenol A with dihydric phenols having pendent amido, N-substituted amido and/or hydroxyalkyl moieties such as 2,2-bis(4-hydroxyphenyl)acetamide and 3,5-dihydroxybenzamide.

Amide and hydroxymethyl functionalized polyethers as thermoplastic barrier resins

Poly(hydroxy amide ethers) which exhibit high barrier properties are prepared by contacting one or more amide-containing bisphenols and an epihalohydrin. These polymers are suitable for use in the manufacture of articles such as rigid containers and flexible films exhibiting high barrier to oxygen transmission in moist environments.

Hydroxy-functional poly(amide ethers) as thermoplastic barrier resins

A thermoplastic composite is prepared by applying a hydroxy-phenoxyether polymer onto the surface of reinforcing fibers or by the in-situ polymerization of mixtures of diepoxides and difunctional species in the presence of reinforcing fibers. The composites can be molded into shaped articles useful for structural materials and parts by conventional thermoforming or other fabrication techniques.

Hydroxy-phenoxyether polymer thermoplastic composites

Novel phosphorus element-containing crosslinking agents for epoxy resin compositions based on an isomeric mixture of tris(2-hydroxyphenyl)-phosphine oxide compounds. Epoxy resins cured or crosslinked with the crosslinking agents of this invention yield non-halogenated, ignition resistant epoxy resin formulations. The ignition resistant epoxy resin formulations are advantageously used for making laminates for printed wiring boards and composite materials.

Phosphorus element-containing crosslinking agents and flame retardant phosphorus element-containing epoxy resin compositions prepared therewith

The synthesis of a series of new high-barrier poly(hydroxy amide ethers) is described The polymers are formed by the reactions of aromatic diglycidyl ethers, with N,N‘-bis(3-hydroxyphenyl)adipamide, HOC6H4NHCO(CH2)4CONHC6H4OH, at 140−160 °C in propylene glycol monophenyl ether solvent using ethyltriphenylphosphonium acetate as initiator Poly(hydroxy amide ethers) of general structure [−CH2CH(OH)CH2OArOCH2CH(OH)CH2OC6H4NHCO(CH2)4CONHC6H4O−]n are readily prepared in high molecular weight The mainly amorphous thermoplastics have glass transition temperatures (Tg) of 78−146 °C and oxygen transmission rates (O2TR) that range from 02 to 18 cc·mil/(100 in2·atm·day) (barrier units or BU) at 23 °C and 45−90% relative humidity It was determined that barrier properties improve (ie, O2TR decreases) as the aromatic core unit, Ar, becomes less bulky or more polar For example, the poly(hydroxy amide ether) in which Ar is the aromatic unit based on 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane has an O

David J. Brennan

Papers

Amide and hydroxymethyl functionalized polyethers as thermoplastic barrier resins

Hydroxy-functional poly(amide ethers) as thermoplastic barrier resins

Hydroxy-phenoxyether polymer thermoplastic composites

Phosphorus element-containing crosslinking agents and flame retardant phosphorus element-containing epoxy resin compositions prepared therewith

High-Barrier Poly(hydroxy amide ethers): Effect of Polymer Structure on Oxygen Transmission Rates. 31