Ultrapermeable, reverse-selective nanocomposite membranes
Ultrapermeable, reverse-selective nanocomposite membranes
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DOI：
10.1126/science.1069580
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发表时间：
2002-04-19
期刊：
影响因子：
56.9
通讯作者：
Hill, AJ
中科院分区：
文献类型：
--
作者：
Merkel, TC;Freeman, BD;Hill, AJ
聚合物纳米复合材料在微电子、有机电池、光学和催化等领域的应用继续受到极大关注。我们已经发现，无孔、纳米级、气相二氧化硅颗粒在玻璃状无定形聚(4-甲基-2-戊炔)中的物理分散同时且令人惊讶地增强了膜渗透性和对大有机分子相对于小永久气体的选择性。与传统填充聚合物系统中获得的结果相比，这些非常不寻常的性能增强反映了气相二氧化硅引起的聚合物链堆积的破坏，以及伴随发生分子传输的自由体积元素尺寸的微妙增加，如正电子湮灭寿命光谱所识别的那样。这种纳米级杂交代表了一种通过系统地操纵分子堆积来调节玻璃状聚合物介质的分离特性的创新方法。
Polymer nanocomposites continue to receive tremendous attention for application in areas such as microelectronics, organic batteries, optics, and catalysis. We have discovered that physical dispersion of nonporous, nanoscale, fumed silica particles in glassy amorphous poly(4-methyl-2-pentyne) simultaneously and surprisingly enhances both membrane permeability and selectivity for large organic molecules over small permanent gases. These highly unusual property enhancements, in contrast to results obtained in conventional filled polymer systems, reflect fumed silica-induced disruption of polymer chain packing and an accompanying subtle increase in the size of free volume elements through which molecular transport occurs, as discerned by positron annihilation lifetime spectroscopy. Such nanoscale hybridization represents an innovative means to tune the separation properties of glassy polymeric media through systematic manipulation of molecular packing.