New Synthetic Methods of Novel Nanoporous Polycondensates and Excellent Oxygen Permselectivity of Their Composite Membranes

• Main Authors: Yu Zang, Toshiki Aoki, Masahiro Teraguchi, Takashi Kaneko, Hongge Jia, Liqun Ma, Fengjuan Miao
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Nanomaterials
• Subjects: synthesis; high oxygen permselectivity; nanopore; nanospace; polyphenylacetylene; polycondensates; highly selective photocyclicaromataization (SCAT)
• Online Access: https://www.mdpi.com/2079-4991/9/6/859

Two kinds of novel nanoporous polycondensates (sc(<b>Rf</b>)) have been synthesized by two new preparation methods consisting of polycondensation and highly selective photocyclicaromataization of 1/3 helical cis-cis polyphenylacetylenes with polymerizable groups. By the original methods, new well-defined sheet polymers having nanopores or nanospaces have been synthesized for the first time. Their composite membranes, containing small amounts (1.0 wt%) of sc(<b>Rf</b>), had ultrahigh oxygen permeability (<i>P</i>o₂ &gt; 1000 barrer), and their plots were beyond the Robeson’s upper bound line in the graph of oxygen permselectivity (<i>α</i> = <i>P</i>o₂/<i>P</i>_N2) versus <i>P</i>o₂. Both <i>α</i> and <i>P</i>o₂ values were enhanced by adding only small amounts (1.0 wt%) of sc(<b>Rf</b>). One of the sc(<b>Rf</b>)s synthesized on the base membrane surface showed the best performance, i.e., <i>P</i>o₂ = 5300 barrer and <i>α</i> = 2.5. The membrane surface was effectively covered by sc(<b>Rf</b>), judging from the contact angle values. It is thought that nanopores and nanospaces created in and between sc(<b>Rf</b>) molecules played an important role for the enhancement of both <i>α</i> and <i>P</i>o₂/<i>P</i>_N2.