Probe Into the Influence of Crosslinking on CO2 Permeation of Membranes

Abstract

Crosslinking is an effective way to fabricate high-selective CO2 separation membranes because of its unique crosslinking framework. Thus, it is essentially significant to study the influence of crosslinking degree on the permeation selectivities of CO2. Herein, we report a successful and facile synthesis of a series of polyethylene oxide (PEO)-based diblock copolymers (BCP) incorporated with an unique UV-crosslinkable chalcone unit using Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT) process. The membranes of as-prepared BCPs show superior carbon dioxide (CO2) separation properties as compared to nitrogen (N2) after UV-crosslinking. Importantly, the influence of different proportions of crosslinked chalcone on CO2 selectivities was systematically investigated, which revealed that CO2 selectivities increased obviously with the enhancement of chalcone fractions within a certain limit. Further, the CO2 selectivities of block copolymer with the best block proportion was studied by varying the crosslinking time which confirmed that the high crosslinking degree exhibited a better CO2/N2 (αCO2/N2) selectivities. A possible mechanism model revealing that the crosslinking degree played a key role in the gas separation process was also proposed.

Synergy of CO2 Response and Aggregation-Induced Emission in a Block Copolymer: A Facile Way To “See” Cancer Cells

“…Traditional CO 2 measurement methods, such as electrochemical, infrared, and gas chromatography–mass spectrometry, and field-effect transistors, have been successfully applied to detect CO 2 concentration in the external environments, especially in space capsules, mines, ships (submarines), and tunnels. − However, these traditional CO 2 measurement methods are not suitable as CO 2 -responsive biological probes because they are generally expensive, not biocompatible, or too large (unable to reach the cancerous tissue within the blood). In recent years, organic CO 2 -responsive molecular systems have attracted great attention. − Guanidine, amidine, tertiary amine, and bulky primary amine functional groups were effectively prepared, which proved to be selective toward CO 2 adsorption. − Among these candidates, the amidine group is the most promising CO 2 -responsive functional group because of its large equilibrium constant ( K t ≈ 10 2 to 10 5 ) with CO 2 , providing the highest CO 2 sensitivity and fastest response. − …”