scholarly journals The immobilisation and reactivity of Fe(CN)63−/4− in an intrinsically microporous polyamine (PIM-EA-TB)

2020 ◽  
Vol 24 (11-12) ◽  
pp. 2797-2806 ◽  
Author(s):  
Lina Wang ◽  
Richard Malpass-Evans ◽  
Mariolino Carta ◽  
Neil B. McKeown ◽  
Frank Marken
Keyword(s):  
Carbon Electrodes ◽  
Microporous Structure ◽  
Polymer Backbone ◽  
Glassy Carbon Electrodes ◽  
Rigid Polymer ◽  
Redox Active ◽  
Microporous Polymer ◽  
Polymer Of Intrinsic Microporosity ◽  
Ph Dependent ◽  
Intrinsic Microporosity

Abstract Protonation of the molecularly rigid polymer of intrinsic microporosity PIM-EA-TB can be coupled to immobilisation of Fe(CN)63−/4− (as well as immobilisation of Prussian blue) into 1–2 nm diameter channels. The resulting films provide redox-active coatings on glassy carbon electrodes. Uptake, transport, and retention of Fe(CN)63−/4− in the microporous polymer are strongly pH dependent requiring protonation of the PIM-EA-TB (pKA ≈ 4). Both Fe(CN)64− and Fe(CN)63− can be immobilised, but Fe(CN)64− appears to bind tighter to the polymer backbone presumably via bridging protons. Loss of Fe(CN)63−/4− by leaching into the aqueous solution phase becomes significant only at pH > 9 and is likely to be associated with hydroxide anions directly entering the microporous structure to combine with protons. This and the interaction of Fe(CN)63−/4− and protons within the molecularly rigid PIM-EA-TB host are suggested to be responsible for retention and relatively slow leaching processes. Electrocatalysis with immobilised Fe(CN)63−/4− is demonstrated for the oxidation of ascorbic acid.

scholarly journals High-Utilisation Nanoplatinum Catalyst (Pt@cPIM) Obtained via Vacuum Carbonisation in a Molecularly Rigid Polymer of Intrinsic Microporosity

2016 ◽  
Vol 8 (2) ◽  
pp. 132-143 ◽  
Author(s):  
Yuanyang Rong ◽  
Daping He ◽  
Richard Malpass-Evans ◽  
Mariolino Carta ◽  
Neil B. McKeown ◽  
...  
Keyword(s):  
Rigid Polymer ◽  
Polymer Of Intrinsic Microporosity ◽  
Intrinsic Microporosity ◽  
High Utilisation

Insight into the reversible conversion-(de)incorporation of redox-active dopants inside polymer-based electrode

2021 ◽  
Author(s):  
Mufan Cao ◽  
Chengyang Xu ◽  
Dewei Xiao ◽  
Zihan Li ◽  
Min Xue ◽  
...  
Keyword(s):  
Electrode System ◽  
Polymer Backbone ◽  
Redox Active ◽  
Microporous Polymer ◽  
Insight Into

We combined a microporous polymer backbone with an organic redox-active dopant to construct a reversible electrode system based on the conversion-(de)incorporation behavior of the dopant. The correspondence between the reversible...

Selective dopamine detection using aptamer-functionalized glassy carbon electrodes

2015 ◽  
Vol 93 (5) ◽  
pp. 572-577 ◽  
Author(s):  
Ryan Walsh ◽  
Uyen Ho ◽  
Xiao Li Wang ◽  
Maria C. DeRosa
Keyword(s):  
Ascorbic Acid ◽  
Electrochemical Detection ◽  
Glassy Carbon ◽  
Dna Aptamer ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Organic Monolayer ◽  
Dopamine Detection ◽  
Redox Active ◽  
Viable Approach

The electrochemical detection of dopamine using glassy carbon electrodes suffers from a lack of selectivity toward the neurotransmitter, as interferences such as other catechol-containing neurochemicals and ascorbic acid can be oxidized at overlapping potentials. Several approaches have been employed to improve the selectivity of these electrodes towards dopamine including electrochemical pretreatment and organic monolayer depositions. Here, we characterize glassy carbon electrodes that were initially passivated through a trifluoromethylphenyl and nitrophenyl monolayer deposition and then functionalized with a specific DNA dopamine aptamer. Passivation with the mixed monolayer cuts off all signals from the redox-active neurochemicals. After functionalization with the DNA aptamer, the dopamine signal is restored and the electrodes are more responsive to dopamine than to any other related catechol-containing compounds or other common neurochemicals such as ascorbic acid. Our findings indicate that aptamer functionalization of glassy carbon electrodes may provide a viable approach for tuning the selectivity of electrochemical detection.

scholarly journals Microporous Polymer Adsorptive Membranes with Unprecedented Processing Capacity for Molecular Separation

2021 ◽  
Author(s):  
Zhenggong Wang ◽  
Xiaofan Luo ◽  
Kuan Lu ◽  
Shouwen Zhu ◽  
Yanshao Yang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Organic Molecules ◽  
Water Flux ◽  
Processing Capacity ◽  
Microporous Polymers ◽  
Modified Polymer ◽  
Molecular Separation ◽  
Microporous Polymer ◽  
Polymer Of Intrinsic Microporosity ◽  
Intrinsic Microporosity

Abstract Trade-off between permeability and nanometer-level selectivity is an inherent shortcoming of membrane-based separation of molecules, while most highly porous materials with high adsorption capacity lack solution processability and stability for achieving adsorption-based molecule separation. We hereby report a hydrophilic amidoxime modified polymer of intrinsic microporosity (AOPIM-1) as a membrane adsorption material to selectively adsorb and separate small organic molecules from water with ultrahigh processing capacity. The membrane adsorption capacity for Rhodamine B reaches 26.114 g m−2, 10~1000 times higher than previously reported adsorptive membranes. Meanwhile, the membrane achieves >99.9% removal of various nano-sized organic molecules with water flux 2 orders of magnitude higher than typical pressure-driven membranes of similar rejections. This work confirms the feasibility of microporous polymers for membrane adsorption with unprecedented capacity, and provides the possibility of adsorptive membranes for molecular separation.

scholarly journals Impedance aspect of charge storage at graphite and glassy carbon electrodes in potassium hexacyanoferrate (II) redox active electrolyte

2016 ◽  
Vol 6 (1) ◽  
pp. 37 ◽  
Author(s):  
Katja Magdić ◽  
Višnja Horvat-Radošević ◽  
Krešimir Kvastek
Keyword(s):  
Glassy Carbon ◽  
Redox Reaction ◽  
Supporting Electrolyte ◽  
Carbon Electrodes ◽  
Charge Storage ◽  
Potassium Hexacyanoferrate ◽  
Impedance Spectra ◽  
Glassy Carbon Electrodes ◽  
Redox Active ◽  
Diffusion Impedance

<p class="PaperAbstract"><span lang="EN-GB">Different types of charge storage mechanisms at unmodified graphite vs. glassy carbon electrodes in acid sulphate supporting solution containing potassium hexacyanoferrate (II) redox active electrolyte, have been revealed by electrochemical impedance spectroscopy and supported by cyclic voltammetry experiments. Reversible charge transfer of Fe(CN)6<sup>3-/4-</sup> redox reaction detected by assessment of CVs of glassy carbon electrode, is in impedance spectra indicated by presence of bulk diffusion impedance and constant double-layer/pseudocapacitive electrode impedance compared to that measured in the pure supporting electrolyte. Some surface retention of redox species detected by assessment of CVs of graphite electrode is in impedance spectra indicated by diffusion impedance coupled in this case by diminishing of double-layer/pseudo­capacitive impedance compared to that measured in the pure supporting electrolyte. This phenomenon is ascribed to contribution of additional pseudocapacitive impedance generated by redox reaction of species confined at the electrode surface.</span></p>

scholarly journals Zeolite-like performance for xylene isomer purification using polymer-derived carbon membranes

2021 ◽  
Vol 118 (37) ◽  
pp. e2022202118
Author(s):  
Yao Ma ◽  
Nicholas C. Bruno ◽  
Fengyi Zhang ◽  
M. G. Finn ◽  
Ryan P. Lively
Keyword(s):  
Ring Structure ◽  
Polymer Backbone ◽  
Carbon Membranes ◽  
Repeat Units ◽  
Current State ◽  
Polymer Of Intrinsic Microporosity ◽  
Two Factors ◽  
Polymers Of Intrinsic Microporosity ◽  
Intrinsic Microporosity ◽  
Xylene Isomer

Polymers of intrinsic microporosity (PIMs) have been used as precursors for the fabrication of porous carbon molecular sieve (CMS) membranes. PIM-1, a prototypical PIM material, uses a fused-ring structure to increase chain rigidity between spirobisindane repeat units. These two factors inhibit effective chain packing, thus resulting in high free volume within the membrane. However, a decrease of pore size and porosity was observed after pyrolytic conversion of PIM-1 to CMS membranes, attributed to the destruction of the spirocenter, which results in the “flattening” of the polymer backbone and graphite-like stacking of carbonaceous strands. Here, a spirobifluorene-based polymer of intrinsic microporosity (PIM-SBF) was synthesized and used to fabricate CMS membranes that showed significant increases in p-xylene permeability (approximately four times), with little loss in p-xylene/o-xylene selectivity (13.4 versus 14.7) for equimolar xylene vapor separations when compared to PIM-1–derived CMS membranes. This work suggests that it is feasible to fabricate such highly microporous CMS membranes with performances that exceed current state-of-the-art zeolites at high xylene loadings.

scholarly journals Catechin or quercetin guests in an intrinsically microporous polyamine (PIM-EA-TB) host: accumulation, reactivity, and release

RSC Advances ◽  
2021 ◽  
Vol 11 (44) ◽  
pp. 27432-27442
Author(s):  
Lina Wang ◽  
Richard Malpass-Evans ◽  
Mariolino Carta ◽  
Neil B. McKeown ◽  
Shaun B. Reeksting ◽  
...  
Keyword(s):  
Polymer Materials ◽  
Guest Species ◽  
Microporous Polymer ◽  
Intrinsic Microporosity

Microporous polymer materials based on molecularly “stiff” structures provide intrinsic microporosity, typical micropore sizes of 0.5 nm to 1.5 nm, and the ability to bind guest species.

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