Morphology control in mesoporous carbon films using solvent vapor annealing.
Morphology control in mesoporous carbon films using solvent vapor annealing.
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DOI：
10.1021/la304915j
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
Zhe Qiang;Jiachen Xue;Kevin A. Cavicchi;B. Vogt
中科院分区：
文献类型：
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作者：
Zhe Qiang;Jiachen Xue;Kevin A. Cavicchi;B. Vogt
通过可逆加成-断裂链转移（RAFT）聚合法合成了一种新型的嵌段共聚物模板（聚苯乙烯-嵌段-N，N-二甲基-正十八胺对苯乙烯磺酸盐（PS-b-PSS-DMODA）），并利用酚醛树脂低聚物与模板的协同自组装制备了有序介孔碳膜（2-50 nm）。由于PS链段的高Tg和酚醛树脂与PSS-DMODA之间的强相互作用，链段重排相对于酚醛树脂的交联速率受到动力学阻碍，这抑制了长程有序化并产生具有宽孔径分布的有序性差的中孔碳。然而，相对较短的曝光（2小时），以控制蒸汽压的甲基乙基酮（MEK）产生显着改善的长程有序和缩小的孔径分布。平均孔径随着退火过程中溶剂蒸气压的增加而增加，但存在p/p0 = 0.85的上限，高于该上限，薄膜在溶剂蒸气退火过程中迅速去湿。这种方法可以使用异亚丙基丙酮来扩展，异亚丙基丙酮具有与MEK类似的溶剂性质，但在溶剂退火后不易通过环境空气干燥除去。该残留溶剂可影响在膜的交联期间形成的形态。这些结果说明了通过简单改变工艺而在初始流延膜中没有任何组成变化来微调有序中孔碳膜的介观结构的能力。
Ordered mesoporous (2-50 nm) carbon films were fabricated using cooperative self-assembly of a phenolic resin oligomer with a novel block copolymer template (poly(styrene-block-N,N-dimethyl-n-octadecylamine p-styrenesulfonate), (PS-b-PSS-DMODA)) synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Due to the high Tg of the PS segment and the strong interactions between the phenolic resin and the PSS-DMODA, the segmental rearrangement is kinetically hindered relative to the cross-linking rate of the phenolic resin, which inhibits long-range ordering and yields a poorly ordered mesoporous carbon with a broad pore size distribution. However, relatively short exposure (2 h) to controlled vapor pressures of methyl ethyl ketone (MEK) yields significant improvements in the long-range ordering and narrows the pore size distribution. The average pore size increases as the solvent vapor pressure during annealing increases, but an upper limit of p/p0 = 0.85 exists above which the films dewet rapidly during solvent vapor annealing. This approach can be extended using mesityl oxide, which has similar solvent qualities to MEK, but is not easily removed by ambient air drying after solvent annealing. This residual solvent can impact the morphology that develops during cross-linking of the films. These results illustrate the ability to fine-tune the mesostructure of ordered mesoporous carbon films through simple changes in the processing without any compositional changes in the initial cast film.