Adsorption and desorption of complex metal ions in polyviologen or its polyion complexes with poly(sulphonate)s by the control of a given potential

Complex anions and a complex cation were concentrated electrostatically in the domain of polyviologen by the control of a given potential. Pyrolytic graphite electrodes were coated with polyviologen or the polyion complex of polyviologen with poly (sulphonic acid) for the concentration of complex anions or the complex cation, respectively. In an aqueous solution in which Mo(CN)^4?₈ and Fe(CN)^4?₆ coexisted, the polyviologen-coated electrode predominantly concentrated Mo(CN)^4?₈. Furthermore, the Mo(CN)^4?₈ incorporated in the film was desorbed by reducing the charge density of polyviologen. The desorption rate was proportional to the charge density of polyviologen which depended on a given potential. On the other hand. Ru(NH₃)³⁺₆ was adsorbed in the domain of the polyion complex of polyviologen with poly (sulphonic acid) and it was desorbed completely in a few seconds by reducing the overall charge density of the polyion complex. Generally, reversible adsorption-desorption of multivalentions could be performed by changing the given potential if redox-active sites were fixed or chemically bonded in the polymer matrix. Redox-active polymers were stabilized by polyion complex formation with oppositely charged polyelectrolytes.     

聚甲基丙烯酸烷基磺酸盐—聚双吡啶分子复合物研究

高分子烷基磺酸盐与聚双吡啶在溶液中形成的大分子复合物具有很好的电化学稳定性。在三元溶剂中的最大溶解度为1.58g/ml;在—0.0v和—0.6v电压下分别显示无色和蓝紫色,响应时间为100ms。     

Electrochemical preparation and properties of composite films with polypyrrole/poly(styrene sulfonate): polyviologen multilayers

Multilayers consisting of polypyrrole/poly(styrene sulfonate) (PP/PSS) and polyviologen (PV) were electrochemically prepared on Au to enhance long-term and environmental (e.g., pH) stability of PV modified electrodes. PV cationic polyelectrolytes were adsorbed on top of electrochemically synthesized PP/PSS via electrostatic interactions with PSS present at the surface of conducting polymer substrates. By alternating electrochemical synthesis of PP/PSS and PV adsorption in a single medium, multilayers were prepared up to 13 layer-pairs. The electrochemical and electrochromic properties of multilayers produced in this way were quite reproducible, since the film preparation does not require medium changes and the layer thicknesses can be finely controlled using the applied potential and time. Although the redox potential of PP/PSS shifted in the positive direction with increase in the number of layer-pairs, cyclic voltammograms of multilayers indicated that total electroactivity of PP/PSS was retained. PV molecules, sandwiched between reduced PP/PSS layers, were also fully electroactive and quite stable during repeated redox switching processes, indicative of enhanced long-term stability. Multilayers also possessed electrochromic properties which were directly proportional to the number of PV layers.     

侧链型烷基联吡啶聚合物的电化学性能

合成了三种不同侧链封端基团的联吡啶聚合物PRV,其中R分别为乙基、正丁基和正壬基。循环伏安特性和紫外-可见光谱表明,其电化学活性的大小顺序为乙基>正丁基>正壬基;三者的电化学稳定性良好,其还原态均显示红紫色。