In this paper, we report a novel electrochemical doping method for conducting polymer films based on bipolar electrochemistry. The electrochemical doping of conducting polymers such as poly(3-methylthiophene) (PMT), poly(3,4-ethylenedioxythiophene) (PEDOT), and poly(aniline) (PANI) on a bipolar electrode having a potential gradient on its surface successfully created gradually doped materials. In the case of PEDOT film, the color change at the anodic side was also observed to be gradually transparent. PANI film treated by the bipolar doping gave a multicolored gradation across the film. The results of UV-vis and energy dispersive X-ray analyses for the doped films supported the distribution of dopants in the polymer films reflecting the potential gradient on the bipolar electrode. Furthermore, the reversibility of the bipolar doping of the PMT film was demonstrated by a spectroelectrochemical investigation.

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The electro-click reaction of azide-functionalized poly(3,4-ethylenedioxythiophene) (PEDOT-N 3 ) and a terminal alkyne was investigated using electrogenerated Cu(I) species on a bipolar electrode in a gradient manner. The introduction of a perfluoroalkyl group derived from the alkyne moiety onto the PEDOT surface only at the cathodic part of the bipolar electrode was successfully characterized by X-ray analyses and the surface properties of the modified film were studied. The spectroscopic analysis of the rhodamine-functionalized PEDOT prepared similarly in a gradient manner was also performed with a UV−vis spectrophotometer.

A novel patterning method for conducting polymer films was successfully demonstrated using the concept of bipolar electrochemistry. The local application of an anodic potential to poly(3-methylthiophene) (PMT) and poly(3,4-ethylenedioxythiophene) (PEDOT) on a bipolar electrode (BPE) realized local electrochemical doping and reaction depending on the supporting salt used. The potential applied on the BPE was measured and corresponded well to the patterns. The array-type driving electrode system was able to draw complex patterns in a site-controlled manner.

Alkaliphilic and thermophilic Bacillus sp. strain TAR-1, isolated from soil, produced a xylanase extracellularly. The xylanase was most active over a pH range of 5.0 to 9.5 at 50°C. Optimum temperatures of the crude xylanase preparation were 75°C at pH 7.0 and 70°C at pH 9.0. Zymogram analyses of the culture supernatant showed that the molecular mass of the xylanase was 40 kDa and the isoelectric point was pH 4.1. The predominant products of xylan hydrolysate were xylobiose, xylotriose, and higher oligosaccharides, indicating that the enzyme was an endoxylanase. Production of the thermophilic alkaline xylanase was induced by xylan and xylose, but was repressed in the presence of glucose.