Bicontinuous nanoporous polymers by carbon dioxide foaming
Bicontinuous nanoporous polymers by carbon dioxide foaming
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DOI：
10.1021/ma010854j
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发表时间：
2001-12-04
期刊：
影响因子：
5.5
通讯作者：
Wessling, M
中科院分区：
文献类型：
--
作者：
Krause, B;Sijbesma, HJP;Wessling, M
我们调查的物理发泡过程的玻璃态聚（醚酰亚胺）和聚（醚砜），使用二氧化碳和报告的温度-浓度图（“泡沫图”）标记出的发泡信封中，致密的CO2饱和膜膨胀和微孔的介绍。观察到两种类型的孔隙。在低于50 cm（3）（STP）/cm（3）（聚合物）的二氧化碳饱和水平下发生闭合微孔结构;在高于该CO2浓度阈值时发生孔径小至40 nm的纳米多孔双连续（开放）结构，这对于两种聚合物是相同的。基于气体渗透测量，详细描述了蜂窝状到双连续过渡的特征，并表示为发泡图内的单独窗口。本文首次报道了向双连续结构的转变，并对它的一般物理基础作了批判性的评述。
We investigate the physical foaming process of glassy poly(ether imide) and poly(ether sulfone) using carbon dioxide and report temperature-concentration diagrams ("foam diagrams") marking out the foaming envelope in which dense CO2-saturated films expand and microvoids are introduced. Two types of porosities are observed. Closed microcellular structures occur at carbon dioxide saturation levels below 50 cm(3) (STP)/cm(3) (polymer); nanoporous bicontinuous (open) structures with pore sizes as small as 40 nm occur above this CO2 concentration threshold, which is identical for both polymers. The cellular-to-bicontinuous transition is characterized in detail on the basis of gas permeation measurements and is represented as a separate window inside the foaming diagram. In this paper, the transition to bicontinuous structures is reported for the first time, and its generic physical basis is critically reviewed.