Researchers at Peking University and Tianjin University in China have developed a method to prepare homogeneous and hierarchical-porosity conjugated microporous polymers (CMPs) with tunable pore structure and enhanced sorption performance.
The method, based on the Glaser coupling reaction (Hay’s condition), involves a fluorosurfactant-assisted gelation to alter the reaction path of the Glaser coupling and the chemical composition of the final materials. This contributes to efficient modulation of the pore-size distribution and gas-sorption properties, as well as to gaining a higher hydrophobicity for selective oil sorption.
The role of the fluorosurfactant in the process is threefold:
i) It can adsorb on the gas–liquid surface and block the penetration of oxygen from air into solution during the reaction process, thus realizing a uniform distribution of dissolved oxygen (DO) and resulting in homogeneous gels;
ii) It has nitrogen and oxygen atoms with lone electron pairs, which are capable of reducing the polymerization degree and altering the final pore structures by coordinating the CuCl catalyst;
iii) The high hydrophobicity of the fluorinated alkyl chain can increase the hydrophobicity of materials, triggering a more-efficient oil-uptake process.
The new CMP aerogels synthesized in this work are studied by IR spectroscopy, freeze drying, and nitrogen sorption/desorption isotherms, as well as oil-sorption experiments. They display not only high gas sorption for carbon dioxide and methane, but also exceptional performance in the clean up of oil and other organic solvents, outperforming must current microporous organic polymers (MOPs).
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