Preparation of chemical vapor sensing materials from composites of esterified poly(vinyl alcohol) and carbon black

Poly(vinyl alcohol) was modified by esterification to prepare poly(vinyl alcohol) copolymers. The degree of esterification on poly(vinyl alcohol) was elucidated by FTIR, ¹H NMR, and elemental analysis. The obtained products were poly(vinyl benzoate)-co-poly(vinyl alcohol) (B-PVA) and poly(vinyl p-toluoate)-co-poly(vinyl alcohol) (P-PVA). The chemical vapor sensors were fabricated by the mixtures of polymer and carbon black in dimethyl sulfoxide and their subsequent preparation as thin films onto the interdigited electrodes by the application of the spin-coating technique. The chemical vapor sensing properties of the sensors were examined with various solvents, such as hexane, toluene, methanol, ethanol, isopropanol, tetrahydrofuran, ethyl acetate, acetonitrile, dimethyl sulfoxide, and water. The experimental results indicated that modifying the chemical structure of PVA results in the decreased polarity of the obtained products. The composites of modified PVA consequently responded well to low polarity solvents, such as THF or ethyl acetate.     

Functionalized poly (vinyl alcohol) polymer as chemodosimeter material for the colorimetric sensing of cyanide in pure water

New poly (vinyl alcohol) (PVA) derivative containing pendant chemoselective functionality is prepared for the cyanide detection in pure water. Particularly, incorporation of the chemodosimeter 4 on PVA is performed by direct coupling of the hydroxyl group of the dye 4 and PVA hydroxyl groups via ethereal linkage using di-bromoalkane as a cross-linking agent. The chemosensory capacity of the polymeric material for the colorimetric sensing of cyanide in water is based on the reactivity of this anion toward the chemodosimeter, and its water solubility is given by PVA moiety. The chemodosimeter is developed on the basis of the trifluoroacetyl group as electrophile receptor of the cyanide anions. The final water soluble functionalized polymer presents a sensible selectivity toward cyanide anions in pure water.     

用Origin软件进行聚乙烯醇胶凝特性研究

提出了一种用线性相关性分析聚乙烯醇溶液在Na_2B_4O_7·10H_2O的水溶液引发下的胶凝特性的方法。建立了聚乙烯醇溶液表观粘度随引发剂加入量变化关系的数学模型,给出了两种线性相关性分析方法。用Origin 6．1分析了胶凝过程的数据特点并给出了参数特征。当引发剂加入量(相对于聚乙烯醇溶液的体积分数)≤0．23%时,表观粘度对引发剂加入量呈较高的线性正相关性；随着引发剂加入量的增加,线性相关性破坏,至引发剂加入量0．929%时,表观粘度随引发剂加入量呈近指数增加。整个过程表观粘度对引发剂加入量可用模型η=-282．994 2857．966V 21939．843exp[(V-2．051)/0．113]进行拟合,相关系数r~2=0．99581。按此模型得胶凝转变点Na_2B_4O_7·10H_2O的水溶液加入量为2．051%,对应的聚乙烯醇溶液表观粘度为27518．6 mPa·s。XRD分析结果表明,该加入量引发后的聚乙烯醇完全转变为非晶态。     

Development of a new fluorescent sensor based on a triazolo-thiadiazin derivative immobilized in polyvinyl chloride membrane for sensitive detection of lead(II) ions

A new sensor membrane based on a novel triazolo-thiadiazin derivative immobilized in polyvinyl chloride has been developed for the determination of Pb(II) ions that displays excellent performance. The parameters involved in the preparation of the optode and determination of Pb(II) were optimized. Under the optimal conditions, the proposed sensor displays a calibration response for Pb(II) over a wide concentration range of 5.0 × 10⁻⁸ to 3.8 × 10⁻⁴ M with the detection limit of 2.2 × 10⁻⁸ M. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity over common metal ions. The optode membrane developed is easily prepared, stable, rapid, and simple for the determination of Pb(II). The accuracy of the proposed sensor was confirmed by analyzing standard reference materials of natural water and surface water. The sensor was successfully used for the determination of Pb(II) ions in water samples with satisfactory results.     

Poly(vinyl alcohol)-based photosensitive water-borne coating for low-temperature color-filter production

A photosensitive water-borne overcoat comprising poly(vinyl alcohol), a glycoluril crosslinker, and a water-soluble photoacid generator was developed. The passivation coating has two features: low-temperature processability and applicability to organic-solvent-susceptible films. Photo-exposure and subsequent baking at 85 °C and development with water produced PGMEA-insoluble and transparent overcoat patterns. Uncured color patterns that were susceptible to the PGMEA-based coating solution remained intact after water-based overcoat application. By exploiting the features of the passivation coating, color patterns of green, red, and white were produced onto a glass substrate at a process temperature of 85 °C.