Controlled Postassembly Functionalization of Mesoporous Copolymer Membranes Informed by Fourier Transform Infrared Spectroscopy AITranslate

Basic Information:

DOI：https://doi.org/10.1021/acsapm.9b00419

Chinese Library Classification Number:

Citation Information:

The need for nanofiltration membranes with tailored selectivity and reduced fouling propensity has led to the development of a multitude of processes that incorporate targeted functionality on membrane surfaces. These processes are often time-consuming, and additional development is needed to realize functionalization protocols that are compatible with roll-to-roll membrane fabrication processes. This work investigated the use of copper-catalyzed azide–alkyne cycloaddition (CuAAC) click reactions whereby a reactive solution containing an alkynyl-terminated molecule is deposited on a copolymer membrane with azide-functionalized surfaces. The progress of the reaction was quantified by using Fourier transform infrared spectroscopy to monitor the decreasing intensity of the peak associated with the azide groups as a function of time. The rate of membrane functionalization was controlled through the concentrations of the copper catalyst and alkynyl-terminated molecule in the reactive solution. Reactive solutions containing 0.1 mol of CuSO4 per mole of alkynyl-terminated reactant (0.1 Cu:Alkyne) resulted in slow reaction rates whereby diffusion created a uniform concentration profile of the alkynyl-terminated molecule across the membrane thickness. These conditions resulted in full conversion of the azide groups in 10–15 μm thick membranes within 5–25 min. For reactive solutions with a value of 0.3 Cu:Alkyne, the nearly instantaneous reaction rate resulted in a reactive front that penetrated into the membrane to achieve full conversion in 60–180 s. Energy dispersive X-ray spectroscopy was used to visualize the progression of the reactive front. Moreover, a model that predicts the penetration of the reactive front, and hence the percent conversion of the azide moieties, as a function of the reactive solution formulation and processing time was developed and validated. These findings offer a controlled functionalization protocol with reactive front velocities that are compatible with roll-to-roll processing rates.