Atmospheric pressure plasma - ARGET ATRP modification of poly(ether sulfone) membranes: A combination attack

Keating, John J.; Sorci, Mirco; Kocsis, István; Setaro, Angelo; Barboiu, Mihail; Underhill, Patrick T.; Belfort, Georges

doi:10.1016/j.memsci.2017.10.014

Cited by 22 publications

(6 citation statements)

References 34 publications

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“…The reducing agent could also act as an indirect oxygen scavenger as well as continually reduce irreversibly produced higher oxidation state complexes formed through termination reactions. This allowed for the ARGET ATRP polymerization to be carried out in small flasks or vials, without the need for special handling of the transition metal complexes and running the reaction under an inert atmosphere. − It also required much less transition metal catalyst, since the reducing agent could continuously regenerate the lower oxidation state form of the catalyst. The advent of ARGET ATRP, therefore, made available the RDRP technique to many laboratories and industrial scale production.…”

Section: Introductionmentioning

confidence: 99%

Predictive Tool for Design and Analysis of ARGET ATRP Grafting Reactions

2017

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Solving a comprehensive, yet simple, reaction model for describing the activators regenerated by electron transfer (ARGET)–atom transfer radical polymerization (ATRP) reaction cascade, we show that the molar ratios of transition metal catalyst to initiator and reducing agent to catalyst are critical parameters in the ARGET ATRP mechanism, with optimal values on the order of 0.1:1 and 10:1, respectively. The model also predicts an optimal molar ratio of reducing agent to initiator of 1:1. The ARGET ATRP reaction cascade is extremely complex with many adjustable species concentrations and reaction parameters. The effect of varying any of these parameters on the resulting temporal conversion trajectory of the polymerization is not straightforward. This analysis greatly simplifies the process allowing one to select the proper conditions to optimize the reaction and could save much effort, time and money. These results have severe implications when grafting polymer chains from surfaces, since the amount of surface-bound initiator is very low relative to the amount of catalyst. This suggests adding a sacrificial initiator to the reaction solution when grafting from surfaces is necessary to prevent loss of control on the polymerization. The most viable parameter for both increasing the polymerization rate and maintaining maximum attainable conversion for the ARGET ATRP system is to increase the reaction temperature. For broad use, the model was developed in MATLAB to predict conversion versus time behavior in the ARGET ATRP reaction cascade using an inexpensive ligand. Utilizing known rate constants and pre-exponential factors to the Arrhenius equations from the literature, the model was able to predict published experimental data for the methyl methacrylate (MMA), styrene (St), and glycidyl methacrylate (GMA) monomers at various temperatures. The main assumptions of the model are that termination reactions occur through radical coupling only and the propagation and termination reaction rates are chain length independent. The resulting model is shown to be very accurate, especially at conversions of 0.4 and lower. Sensitivity analyses were performed on the ARGET ATRP mechanism using MMA as a model monomer to identify key reaction parameters to ensure successful controlled polymerization.

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Section: Introductionmentioning

confidence: 99%

Predictive Tool for Design and Analysis of ARGET ATRP Grafting Reactions

2017

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“…By activating the membrane polymer before fabrication or by using membrane polymers containing hydroxyl groups ( e.g. , cellulose), porous polymeric membranes have been modified ( via SI-ATRP) with covalently grafted defined polymer brushes by attaching the ATRP initiator to a previously activated surface. ,, For example, Xu et al activated a nylon solvent-stable membrane in formaldehyde and then attached the ATRP initiator . Zhao et al demonstrated free-radical grafting of an anchoring polymer onto polypropylene MF membranes followed by postgraft modification with an ATRP initiator in tetrahydrofuran to facilitate the grafting of PSBMA brushes .…”

Section: Introductionmentioning

confidence: 99%

Zwitterion Polymer Brushes on Porous Membranes: Characterization, Tribology, Performance, and the Effect of Electrolyte Anions

Ziemann

Coves

Levin

et al. 2020

ACS Appl. Polym. Mater.

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Herein, we present a two-step activation process to achieve surface-initiated atom transfer radical polymerization (ATRP) and covalently grafted poly(sulfobetaine methacrylate) polyzwitterion brushes with controlled density and thickness on polyacrylonitrile (PAN) ultrafiltration membrane surfaces. The activation is based on the known amidoxime synthesis on PAN membrane surfaces, with subsequent mixed oxadiazole formation to incorporate the ATRP initiator. Successful grafting and the differences in brush density and thickness were verified by X-ray photoelectron spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, and atomic force microscopy (AFM). Specifically, we qualitatively show the differences in the brush interface layers by using lateral force microscopy (LFM) with a colloidal AFM probe and through nanowear experiments using a sharp AFM tip. All brush interfaces showed reduced friction in LFM and unique stick-slip behavior and ripple formation as a nanowear mode. We also show that the molecular weight cutoff and permeability vary with the brush properties and that both highand low-density brushes offer superior antifouling properties against alginate compared to a pristine PAN membrane. Finally, we analyze how Hofmeister series anions affect filtration with 0.01, 0.1, and 0.5 mol L −1 KCl, KBr, KSCN, K 2 SO 4 , and K 2 HPO 4 solutions. The results reveal a positive flux effect for KCl, KBr, and KSCN and a negative one for K 2 SO 4 and K 2 HPO 4 solutions, suggesting that the brushes are grafted mostly to the surface, crowding the pore mouth in the media with strongly hydrated counterions. Overall, this work provides a method for preparing well-controlled polymer brushes on porous membranes to produce membranes with excellent antifouling properties.

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“…3 The ARGET-ATRP reaction system is complex with many adjustable parameters that affect the resulting temporal conversion trajectory in a non-linear fashion. When grafting polymer chains from surfaces, which is of interest to catalysis and separation processes like chromatography and membrane filtration, 4 the most viable parameters for both increasing the polymerization rate and reaching maximum conversion for the ARGET-ATRP system is to increase the reaction temperature and maintain a large amount of sacrificial initiator in the reaction solution.…”

Section: Introductionmentioning

confidence: 99%

A Simplified Predictive Tool for Design and Analysis of SET-LRP Reactions with Mechanistic Insight

Gunter

Sorci

Belfort

2020

ACS Appl. Polym. Mater.

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Single-electron transfer (SET)-living radical polymerization (LRP) is a robust, fast, “green,” grafting method, similar but different from atom transfer radical polymerization, that operates at ambient temperature in the presence of oxygen and is industrially attractive. Solving a simplified reaction model with only five rather than 12 reactions in solution, for describing the SET-LRP scheme and verifying it with experimental data, we provide (i) a useful tool to predict conversion given initial conditions and rate constants, and (ii) key mechanistic insights with a parametric sensitivity analysis, illustrating the effects of initial conditions, kinetic rate constants, temperature, and copper particle size. Findings include: (i) Increasing the formation rate of radicals (i.e., k act) exhibited a maximum in monomer conversion. (ii) The optimal ratio of initial conditions was found to be [MA]0/[PnX]0/[CuIIX2/L]0 = 222/1/1.5, where [MA]0 = 7.4 M. (iii) Increasing the temperature strongly improved monomer conversion with an inflection point. (iv) Using an order-of-magnitude and Damköhler number analysis, we provide a rationale for selecting small diameter particles and specify how they are likely to perform with SET-LRP reactions. Assumptions of the model include: Solid copper concentration was an infinite source of dissolved CuI and CuII and was available instantaneously (with Damköhler number ≪ 1, for reaction rather than diffusion limitation). Also, the reverse reaction of the disproportionation of CuI was negligible, polymer chain length did not affect reaction kinetics, and all intermediate reactions were neglected.

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Atmospheric pressure plasma - ARGET ATRP modification of poly(ether sulfone) membranes: A combination attack

Cited by 22 publications

References 34 publications

Predictive Tool for Design and Analysis of ARGET ATRP Grafting Reactions

Predictive Tool for Design and Analysis of ARGET ATRP Grafting Reactions

Zwitterion Polymer Brushes on Porous Membranes: Characterization, Tribology, Performance, and the Effect of Electrolyte Anions

A Simplified Predictive Tool for Design and Analysis of SET-LRP Reactions with Mechanistic Insight

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