Block copolymers containing intrinsically proton-conducting blocks tethered with benzimidazole units
Block copolymers containing intrinsically proton-conducting blocks tethered with benzimidazole units
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DOI：
10.1021/cm0602848
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发表时间：
2006-06-27
影响因子：
8.6
通讯作者：
Jannasch, Patric
中科院分区：
文献类型：
--
作者：
Persson, J. Christian;Jannasch, Patric
阿坝三嵌段共聚物具有苯并咪唑栓系的末端嵌段已经制备和表征其固有的质子传导性能。以线性聚环氧乙烷（PEO）为双官能度大分子引发剂，通过烯丙基缩水甘油醚的阴离子开环聚合反应合成了共聚物。末端嵌段的侧链烯丙基随后通过自由基硫醇-烯偶联反应与2-（2-苯并咪唑基）乙烷乙炔连接。热重分析表明，最终材料在氮气气氛下在高达210 ℃下是稳定的。发现共聚物的苯并咪唑单元从溶液中结晶而不是从熔体中结晶。在将材料加热到苯并咪唑单元的熔点以上之后，共聚物显示出单一的玻璃化转变温度（T-g’s）。此外，PEO嵌段的结晶被抑制，这可能表明不同嵌段之间的高度相互作用。质子传导性被发现是促进由高苯并咪唑浓度和高的链段流动性，即，低Tg的共聚物。苯并咪唑浓度的增加提高了T-g，由此产生的电导率取决于载流子密度和迁移率之间的平衡。这些材料在完全无水的条件下，在160 ℃下达到接近80 μ S/cm的电导率。
ABA triblock copolymers having benzimidazole-tethered end blocks have been prepared and characterized with respect to their intrinsically proton conducting properties. The copolymers were synthesized by using a linear poly( ethylene oxide) (PEO) as a difunctional macroinitiator for the anionic ring-opening polymerization of allyl glycidyl ether. The pendent allyl groups of the end blocks were subsequently linked with 2-(2-benzimidazolyl) ethanethiol via a free radical thiol-ene coupling reaction. Thermogravimetry showed that the final materials were stable up to 210 degrees C under a nitrogen atmosphere. The benzimidazole units of the copolymers were found to crystallize from solution but not from the melt. After heating the materials above the melting point of benzimidazole units, the copolymers displayed single glass transitions temperatures (T-g's). Moreover, the crystallization of the PEO blocks was depressed which may indicate a high degree of interaction between the dissimilar blocks. The proton conductivity was found to be promoted by a high benzimidazole concentration and a high segmental mobility, that is, low Tg's of the copolymers. Increased concentrations of benzimidazole raised the T-g, and the resulting conductivity thus depended on a balance between the charge carrier density and the mobility. Conductivities close to 80 mu S/cm were reached at 160 degrees C by these materials under completely anhydrous conditions.