Three kinds of liquid crystalline compounds (AQBD1, AQBD2 and AQBT) having an anthraquinone and a bithiophene moieties were synthesized. The mesophases have been characterized by polarized optical microscopy (POM) observation, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. AQBD1 and AQBT were determined to form colomnar phases while AQBD2 showed a smectic phase. The disc units of the columnar phases of AQBD1 and AQBT were expected to contain 2 and 3 molecules, respectively. The electrochemical properties of AQBT, which keeps the liquid crystalline phase at room temperaure, were examined by cyclic voltammetry (CV) and optoelectrochemical measurements. The reversible electrochemical response of AQBT was confirmed in solution. The reversible color change of EC device prepared from liquid crystalline AQBT (LC-AQBT) was also observed at room temperaure and the positive potentials, which is due to the bithiophene unit.
We herein report an electrical assay for copper(II) (Cu2+) utilizing an organic thin-film transistor (TFT). To endow the metal ion recognition ability, the extended-gate portion in the organic TFT is functionalized by a nitrilotriacetic acid (NTA)-terminated monolayer. As a result, the device responds selectively to Cu2+ in aqueous media. Importantly, the estimated detection limit for Cu2+ (= 96 ppb) is much lower than environmental standard value of a copper contaminant in drinking water. Its superior processability and portability in the organic device indicate that the proposed assay could be applied for on-site detection of the Cu2+ ion without large-sized equipment.
The oxygen evolution reaction of anode catalyst is an important reaction in polymer electrolyte membrane water electrolysis. Recent research has focused on understanding the factors governing the catalytic properties of nanostructured IrO2 in order to decrease the use of expensive and precious IrO2. We demonstrate here the equivalent diameter (De) effect (lateral size effect) of IrO2 nanosheets for the oxygen evolution reaction. IrO2 nanosheets with four different De from 110 to 260 nm and same thickness (∼1.5 nm) were prepared. The electrical double layer capacitance, which should be proportional to the electrochemically active surface area, of IrO2 nanosheets was independent of De. On the other hand, the pseudo-capacitance, which is related to surface redox processes, and the oxygen evolution reaction activity increased with decreasing De. The enhanced oxygen evolution reaction activity is discussed based on the electrochemically active surface area and edge effect.
Electrochemical noise (EN) was used to study the corrosivity of haze under Tianjin’s urban atmosphere by using two electrochemical corrosion probes made by T91 and Q235B steels. Experimental results indicate that temperature, relative humidity and concentrations of pollutants (PM10, PM2.5, SO2, NO2 and O3) can affect the corrosion of T91 and Q235B atmospheric corrosion monitoring probes. However, the atmospheric humidity has a major effect on corrosion activities. The corrosivity of haze under low temperature and high relative humidity has a high level, which can promote the corrosion of T91 and Q235B probes; the effect of atmospheric pollutant concentration on atmospheric corrosivity is not apparent due to theirs low concentrations. T91 probe is suitable for long term corrosion monitoring, while Q235B probe is suitable for short time monitoring and has high detection precision.