甲基纤维素(MC)疏水作用的电化学研究

应用电化学循环伏安法, 以电活性小分子亚甲基蓝(MB)为探针, 研究了不同温度下修饰在玻碳电极表面的甲基纤维素(MC)凝胶的疏水性. 研究发现, 在45～70 ℃温度范围内, MB在MC凝胶修饰电极上的式电位E⁰⁽较相应的裸电极均正移, 氧化峰电流i_pa和还原峰电流i_pc分别较相应裸电极增大, 且随温度升高而增大. 这些结果表明MC分子之间发生了疏水相互作用, 且随温度的升高, 疏水作用增强. 此外, 在上述温度下, MC凝胶修饰电极上峰电流的比值i_pc/i_pa均小于1, 为0.70, 且没有观察到MB单独的吸附峰, 因此MB分子在凝胶修饰电极上发生了弱吸附. 本文研究显示电化学方法是研究该类多糖凝胶机理的一个补充手段.

An Electrochemical Study of the Hydrophobic Interaction of Methylcellulose

n the present work, by using methylene blue (MB) as an electroactive probe, the hydrophobic properties of methylcellulose (MC) coated on a glassy carbon electrode were studied at different temperatures by electrochemical voltammetric method. It was found that, compared with the corresponding bare electrodes, the formal potential E⁰⁽ of MB on the MC modified electrodes shifted positively, and both the cathodic peak current i_pc and anodic peak current i_pa increased with temperature in the range of 45～70 ℃, indicating that hydrophobic bonding occurred between MC macromolecules, and that such an interaction tended to intensify with increasing the temperature. In addition, the ratio of the anodic to the cathodic peak currents i_pc/i_pa of modified electrodes were less than 1, being 0.70, and no single absorption peak of MB was observed on the cyclic voltammograms, which implied MB weakly absorbing on the MC film. The obtained experimental results also showed that the application of electrochemical methods to investigate the gelation mechanism of MC at a molecular level provided a useful complement.