title: The role of the internal molecular free volume in defining organic porous copolymer properties: tunable porosity and highly selective CO₂ adsorption.
abstract: A series of novel azo-functionalized copolymerized networks (simply known as NOP-34 series) with tunable permanent microporosity and highly selective carbon dioxide capture are disclosed. The synthesis was accomplished by Zn-induced reductive cross-coupling copolymerization of two nitrobenzene-like building blocks with different 'internal molecular free volumes' (IMFVs), i.e., 2,7,14-trinitrotriptycene and 2,2',7,7'-tetranitro-9,9'-spirobifluorene, with different molar ratios. Increasing the content of spirobifluorene (SBF) segments with a smaller IMFV relative to that of triptycene leads to an unconventional rise-fall pattern in porosity. Unlike most reported porous copolymers whose surface area lies between the corresponding homopolymers, the copolymer NOP-34@7030 with 30% SBF segments unprecedentedly shows the largest Brunauer-Emmett-Teller specific surface area (up to 823 m(2) g(-1)) as well as promoted CO2 uptake abilities (from 2.31 to 3.22 mmol g(-1), at 273 K/1.0 bar). The 100% triptycene(TPC)-derived homopolymer (NOP-34@1000) with a moderate surface area shows the highest CO2/N2 IAST selectivity of 109 (273 K) among the five samples, surpassing most known nanoporous organic polymers. This may contribute significantly to our understanding of the relationship of IMFVs with the properties of copolymerized materials.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Yindong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: School of Chemistry and Material Science, Guizhou Normal University, Guiyang 550000, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Shuai
authors.initials: S
authors.lastname: Gu
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Fu
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Dongyang
authors.initials: D
authors.lastname: Chen
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Lin
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn and State Key Laboratory of Advanced Technology For Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
authors.forename: Guipeng
authors.initials: G
authors.lastname: Yu
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. gilbertyu@csu.edu.cn panchunyue@csu.edu.cn.
authors.forename: Chunyue
authors.initials: C
authors.lastname: Pan