Ionic self-assembled redox-active polyelectrolyte-ferrocenyl surfactant complexes: Mesomorphous structure and electrochemical Behavior
Ionic self-assembled redox-active polyelectrolyte-ferrocenyl surfactant complexes: Mesomorphous structure and electrochemical Behavior
复制标题
离子自组装氧化还原活性聚电解质-二茂铁基表面活性剂复合物：介晶结构和电化学行为
DOI：
10.1021/ma071072e
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发表时间：
2007-10-16
期刊：
影响因子：
5.5
通讯作者：
Tong, Zhen
中科院分区：
文献类型：
--
作者：
Cheng, Zhiyu;Ren, Biye;Tong, Zhen
通过聚苯乙烯磺酸钠(PSS)和二茂铁基表面活性剂N-烷基(二茂铁甲基)溴化铵(FCN，n=8，12，16，其中n为烷基链的碳数)在溶液中的离子自组装，制备了氧化还原活性的聚电解质-表面活性剂络合物(PSC)。PSS-FCN具有有序的层状介晶结构，其长周期分别为2.49、2.94和3.74 nm。随着表面活性剂烷基链长的增加，体系的堆积有序性得到改善。有趣的是，在固体络合物中，二茂铁基部分形成了H-聚集，从紫外光谱的蓝移可知，环戊二烯在二茂铁部分中的pi-pi*能量转移增加。由于离子相互作用，这些络合物表现出比其组分更高的热稳定性。循环伏安(CV)测试表明，在0.02~4V/S范围内，氧化还原活性复合膜的电极过程是扩散控制的，且几乎可逆或准可逆，尽管PSS-FCl2和PSS-Fc16膜的可逆性比PSS-Fc8膜差。根据表面电荷转移系数αn(α)标准速率常数K_i和反映电极动力学的表观扩散系数D-app的值判断，氧化还原峰电流垂直棒I(P)垂直棒随着络合物中表面活性剂尾长的增加而增加，这是因为由较长的表面活性剂尾形成的络合膜中的有序堆积更有利于电解液的扩散和电荷转移。结果表明，氧化还原活性的聚苯乙烯磺酸盐-二茂铁基表面活性剂络合物的电化学活性可以通过改变表面活性剂的尾长来调节。我们的工作为通过离子自组装制备具有有序介晶结构的氧化还原活性聚合物提供了一种简便易行的方法。
Redox-active polyelectrolyte-surfactant complexes (PSC) were prepared via the ionic self-assembly of sodium poly(styrenesulfonate) (PSS) and ferrocenyl surfactant, n-alkyl (ferrocenylmethyl)ammonium bromide (Fcn, n = 8, 12, 16, where n is the carbon number of the alkyl chain), in solution. The PSS-Fcn complex exhibited an ordered lamellar mesomorphous structure with the long period of d = 2.49, 2.94, and 3.74 nm for PSS-Fc8, PSS-Fcl2, and PSS-Fc16, respectively. With increasing the length of surfactant alkyl chain, the stacking order was improved. Interestingly, in the solid complex, the ferrocenyl moieties formed H-aggregation showing an increase in the pi-pi* energy transfer of cyclopentadienes in the ferrocene moieties as known from the blue shift in the UV spectrum. These complexes showed higher thermal stability compared with their components due to the ionic interaction. Cyclic voltammogram (CV) measurements indicated that the electrode process of these redox-active complex films was diffusion-controlled and almost reversible or quasi-reversible at scan rates ranging from 0.02 to 4 V/s. Though the reversibility of the electrode process became worse for the PSS-Fcl2 and PSS-Fc16 films than that for the PSS-Fc8, the redox peak current vertical bar i(p)vertical bar increased with increasing surfactant tail length in the complex because the more ordered packing in the complex film formed by longer surfactant tails was more favorable for the electrolyte diffusion and charge transfer as judged on values of the surface charge-transfer coefficient alpha n(alpha) standard rate constant K,, and apparent diffusion coefficient D-app reflecting the electrode kinetics. The present results demonstrate that the electrochemical activity of the redox-active poly(styrenesulfonate)-ferrocenyl surfactant complex can be easily tuned by changing the surfactant tail length. Our work provides a simple and facile approach to the preparation of redox-active polymers with ordered mesomorphous structure by the ionic self-assembly.