Noncovalent modification of self‐assembled functionalized COF by PNIPAM and its properties of Pickering emulsion

Based on a facile and universal method using noncovalent bonding, here, polymer‐modified covalent organic framework materials (COFs) were rapidly prepared. PNIPAM‐modified COF (COF‐PNIPAM) was synthesized by electrostatic self‐assembly between COF prepared by low‐cost melamine and terephthalaldehyde...

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Published in:Journal of the Chinese Chemical Society (Taipei) 2020-11, Vol.67 (11), p.2004-2011
Main Authors: Zhang, Na, Wang, Fei, Cai, Chang‐chen, Sun, Qian, Zhang, Kai, Li, Ai‐xiang, Weng, Jun‐ying, Li, Qiu‐hong
Format: Article
Language:English
Subjects:
Addition polymerization
Chain transfer
COFs
Electron microscopes
Fourier transforms
Liquid chromatography
Melamine
noncovalent bonding
Pickering emulsion
PNIPAM
Polyisopropyl acrylamide
Spectrometers
temperature responsiveness
Toluene
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Summary:Based on a facile and universal method using noncovalent bonding, here, polymer‐modified covalent organic framework materials (COFs) were rapidly prepared. PNIPAM‐modified COF (COF‐PNIPAM) was synthesized by electrostatic self‐assembly between COF prepared by low‐cost melamine and terephthalaldehyde and carboxyl‐terminated poly(N‐isopropylacrylamide) (PNIPAM) prepared via reversible addition‐fragmentation chain transfer polymerization. The carboxyl‐terminated PNIPAM was characterized by Gel Permeation Chromatography and Ultraviolet and Visible Spectroscopy (UV–vis). COF and COF‐PNIPAM were characterized by Fourier Transform Infrared Spectroscopes, Scanning Electron Microscope, Transmission Electron Microscope, X‐Ray Diffractomer (XRD), and Brunner‐Emmet‐Teller (BET) measurements. The results showed that the COF‐PNIPAM was successfully prepared. The Pickering emulsion properties of the COF‐PNIPAM in a water‐to‐toluene mixed system were studied, and when the water‐to‐oil ratio is 2:1, a stable emulsion can be obtained. However, the results show that the PNIPAM chains of COF‐PNIPAM nearly lose their temperature responsiveness. A novel method for polymer modification of COF was proposed via noncovalent bonding, which was convenient and easy to implement. The positively charged amino groups of COF and the carboxyl‐terminated groups of HOOC‐PNIPAM‐SH were combined by self‐assembly in water to obtain the COF‐PNIPAM. The emulsifying properties of the obtained copolymer COF‐PNIPAM as Pickering emulsifier were studied.
ISSN:0009-4536
2192-6549
DOI:10.1002/jccs.202000089