Flexible, high mobility short-channel organic thin film transistors and logic circuits based on 4H-21DNTT.

The low mobility and large contact resistance in organic thin-film transistors (OTFTs) are the two major limiting factors in the development of high-performance organic logic circuits. Here, solution-processed high-performance OTFTs and circuits are reported with a polymeric gate dielectric and 6,6 bis (trans-4-butylcyclohexyl)-dinaphtho[2,1-b:2,1-f]thieno[3,2-b]thiophene (4H-21DNTT) for the organic semiconducting layer. By optimizing and controlling the fabrication conditions, a high saturation mobility of 8.

Fast electrochemistry of conductive polymer nanotubes: synthesis, mechanism, and application.

Conductive polymers exhibit several interesting and important properties, such as metallic conductivity and reversible convertibility between redox states. When the redox states have very different electrochemical and electronic properties, their interconversion gives rise to changes in the polymers' conformations, doping levels, conductivities, and colors, useful attributes if they are to be applied in displays, energy storage devices, actuators, and sensors. Unfortunately, the rate of interconversion is usually slow, at best on the order a few hundred milliseconds, because of the slow transport of counterions into the polymer layer to balance charge.

Poly(3,4-ethylenedioxythiophene) nanotubes as electrode materials for a high-powered supercapacitor.

We report the fast charging/discharging capability of poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes during the redox process and their potential application to a high-powered supercapacitor. PEDOT nanotubes were electrochemically synthesized in a porous alumina membrane, and their structures were characterized using electron microscopes. Cyclic voltammetry was used to characterize the specific capacitance of the PEDOT nanotubes at various scan rates.

Controlled electrochemical synthesis of conductive polymer nanotube structures.

We have investigated the electrochemical synthetic mechanism of conductive polymer nanotubes in a porous alumina template using poly(3,4-ethylenedioxythiophene) (PEDOT) as a model compound. As a function of monomer concentration and potential, electropolymerization leads either to solid nanowires or to hollow nanotubes, and it is the purpose of these investigations to uncover the detailed mechanism underlying this morphological transition between nanowire and nanotube. Transmission electron microscopy was used to characterize electrochemically synthesized PEDOT nanostructures and measure the extent of their nanotubular portion quantitatively.

Bias-free pneumatic sample injection in microchip electrophoresis.

We have developed a new microfluidic chip capable of accurate metering, pneumatic sample injection, and subsequent electrophoretic separation. The pneumatic injection scheme, enabling us to introduce a solution without sampling bias unlike electrokinetic injection, is based upon the hydrophobicity and wettability of channel surfaces. An accurately metered solution of 10 nL could be injected by pneumatic pressure into a hydrophilic separation channel through Y-shaped hydrophobic valves, which consist of polydimethylsiloxane (PDMS) and fluorocarbon (FC) film layers.

On-line sample cleanup and chiral separation of gemifloxacin in a urinary solution using chiral crown ether as a chiral selector in microchip electrophoresis.

In chiral capillary electrophoresis of primary amine enantiomers using (+)-18-crown-6-tetracarboxylic acid (18C6H4) as a chiral selector, the presence of alkaline metal ions in the sample solution as well as in the run buffer is undesirable due to their strong competitive binding with 18C6H4. A channel-coupled microchip electrophoresis device was designed to clean up alkaline metal ions from a sample matrix for the chiral analysis of amine. In the first channel, the metal ions in the sample were monitored by indirect detection using quinine as a chromophore and drained to the waste.

Integration of on-column immobilized enzyme reactor in microchip electrophoresis.

A simple method integrating an immobilized enzyme reactor into a microchip electrophoresis device was developed. The enzyme immobilization into a microchip was performed by spotting and drying a drop of dissolved nitrocellulose (NC) on a glass substrate, and adsorbing enzyme on the reconstituted NC membrane. This enzyme-immobilized glass plate was assembled with a polydimethylsiloxane substrate on which the separation channel was fabricated.

Chiral separation of gemifloxacin in sodium-containing media using chiral crown ether as a chiral selector by capillary and microchip electrophoresis.

Chiral crown ether, (+)-(18-crown-6)-tetracarboxylic acid (18C6H(4)), is an effective chiral selector for resolving enantiomeric primary amines owing to the difference in affinities between 18C6H(4) and each of the amine enantiomers. In addition to the destacking effect of sodium ion in the sample solution, the strong affinity of sodium ion to the polyether ring of crown ether is unfavorable to chiral capillary electrophoresis using 18C6H(4) as a chiral selector. In this report, the chiral separation of gemifloxacin dissolved in a saline sample matrix using 18C6H(4) was investigated.