Polyanilines with Pendant Amino Groups as Electrochemically Active Copolymers at Neutral pH

Burr

et al. 2018

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During the last decade, nanofluidic devices based on solid-state nanopores and nanochannels have come into scene in materials science and will not leave anytime soon. One of the main reasons for this is the excellent control over ionic transport exerted by such devices that promises further important advances when integrated into more complex molecular devices. As a result, pH, temperature, and voltage-regulated devices have been obtained. However, nowadays, there is still a necessity for molecule-driven nanofluidic devices. Here, a sugar-regulated pH-responsive nanofluidic diode is presented obtained by surface modification of conical polycarbonate nanochannels with electropolymerized 3-aminophenylboronic acid. Control over the ionic transport has been achieved by a successful decoration of asymmetric nanochannels with integrated molecular systems. The as-synthesized boronate-appended zwitterionic polymer exhibits an acid-base equilibrium that depends on the concentration of sugar, which ultimately acts as a chemical effector setting different pH-dependent rectification regimes. As a result, the same nanodevice can perform completely different proton-regulated nanofluidic operations, i.e., anion-driven rectification, cation-driven rectification, and no rectification, by simply varying the concentration of fructose in the electrolyte solution.

Section: Resultsmentioning

confidence: 75%

Proton‐Gated Rectification Regimes in Nanofluidic Diodes Switched by Chemical Effectors

Pérez-Mitta

Burr

et al. 2018

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“…The electropolymerization of substituted aniline (ANI) monomers with extra pendant amino group, such as 3‐aminobenzylamine (ABA), constitutes a promising strategy toward synthesis of electrode materials which combines the electrical properties of PANI with the chemical richness of the amino moieties. We have recently shown that stable films of copolymers of ANI and ABA (PABA) can be obtained by cyclic voltammetry in acidic solution and then employed in neutral electrolytes . Compared to PANI, the copolymers present increased electroactivity in neutral solution which made them suitable candidates for electrochemical devices operating under biocompatible conditions, such as biofuel cells .…”

Section: Mass Increments Determined By Qcm For Different Composite Elmentioning

confidence: 99%

“…Details of PABA electrosynthesis on gold electrodes have been presented and discussed in a previous work . Experimental and additional data about electropolymerization, characterization of electroactivity and chemical composition of PABA by X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) images of modified substrates are presented in the Supporting Information.…”

Section: Mass Increments Determined By Qcm For Different Composite Elmentioning

confidence: 99%

Metal‐Organic Frameworks Help Conducting Polymers Optimize the Efficiency of the Oxygen Reduction Reaction in Neutral Solutions

Rafti

Azzaroni

2016

Adv Materials Inter

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respect, the theoretical work of Barzukov and co-workers [ 7 ] suggests that the catalysis of the ORR on CPs can be ascribed to the weakening of molecular O O bonds during the chemisorption of oxygen on the polymer surface. For example, in the case of carbon black/PPy composites, the onset potential for ORR (−0.34 V) is more anodic than that observed in carbon blackcoated electrodes (−0.60 V). However, the ORR current densities are highly dependent on the loading of the PPy catalyst because of the low oxygen diffusion in the electrode surface. [ 13 ] In this regard, one of the major challenges for the optimization of electrochemical energy-conversion devices (e.g., metal-air batteries), is to increase the O 2 reduction and evolution effi ciencies, thus requiring the development of new effective electrocatalytic interfacial architectures compatible with the operation in aqueous electrolytes using air as the oxygen source.This point is where MOFs come into the picture as a valuable tool to engineer the oxygen uptake properties of the electrochemical interface in order to increase its concentration on the electrode surface. MOFs represent an emergent and versatile class of microporous materials constituted by an infi nite arrangement of metal (or metal cluster) centers coordinated via noncovalent interactions with organic linkers. [ 14,15 ] A great deal of effort has been devoted also to test strategies directed to control MOFs' growth and to synthesize mixed composites and supported fi lms, [ 16 ] whose distinctive properties have given rise to an increasing number of interesting applications (e.g., mixed matrix membranes for pervaporation, [ 17 ] or thin fi lms for sensor and separation technologies [ 18 ] ).Very recently, Díaz et al. [ 19 ] reported a comprehensive work describing the selective gas adsorption of fi lms constituted by ZIF-8 MOF (a member of a subclass of MOFs known as Zeolitic Imidazole Frameworks, constituted of Co 2+ or Zn 2+ metal ions tetrahedrally coordinated by imidazole-based linkers). It was shown that selectivity of O 2 adsorption over N 2 is close to 6, thus confi rming that ZIF-8 would undergo preferential uptake of O 2 even in the case of atmospheric O 2 :N 2 composition.Taking into account these concepts and being aware of the outstanding features of gas storage exhibited by metal-organic frameworks, we took this new paradigm one step further by integrating MOFs onto CPs and using them as oxygen reservoirs sitting atop the electrocatalytic active material. However, it is important to consider that such interfacial architectures require the tailored production and organization of complex matter displaying spatially addressed chemistry using different wet chemical processes. Therefore, to achieve this goal it is important to test strategies for the controlled preparation of multicomponent nanostructures on surfaces. Research efforts The oxygen reduction reaction (ORR), where molecular oxygen is electrocatalytically reduced on the electrode surface, plays a decisive role in energy conver...

“…The N1s core spectrum level of PABA can be deconvoluted into 5 peaks as previously reported. 23,24 The backbone N atoms are considered to contribute with 4 bands corresponding to the uncharged N species and positive N species from oxidized secondary amines and protonated imine (Fig. 1).…”

Section: Xpsmentioning

confidence: 99%

“…Additionally, PABA also displays enhanced electroactivity in neutral solutions compared with PANI. 23,24 Owing to its improved processability in aqueous solution, PABA seems to be a better candidate than PANI for the preparation of electrostatically-driven complexes with surfactants. On the other hand, the particular interaction between protonated amines and phosphate anions has been extensively recognized.…”

mentioning

confidence: 99%

Electrochemical nanoarchitectonics through polyaminobenzylamine–dodecyl phosphate complexes: redox activity and mesoscopic organization in self-assembled nanofilms

Lorenzo

Phys. Chem. Chem. Phys.

Maza

et al. 2018

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