scholarly journals Micro- and Nanostructured Polyaniline for Instant Identification of Metal Ions in Solution

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 231 ◽  
Author(s):  
Agnieszka Michalska ◽  
Sebastian Golczak ◽  
Krzysztof Langer ◽  
Jerzy Langer
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Current Flow ◽  
Integral Intensity ◽  
Ion Current ◽  
Organic Polymer ◽  
Self Assembled Monolayer ◽  
New Device ◽  
Concentration Of Ions ◽  
Easy Operation

The unique properties of nanomaterials enable the creation new analytical devices. Polyaniline (PANI) micro- and nanofiber network, freestanding in the gap between two gold microelectrodes, has been used in a new nanodetector for metal ions in solutions. The gold electrodes were modified with the aid of alkanethiols, forming a self-assembled monolayer (SAM), which is able to block the ion current flow, but also to interact with metal ions when specific functional molecules are incorporated into the layer. The electric field of the trapped metal ions induces change of the electrical conductivity of polyaniline nanofibers in vicinity. A small injected sample (75 μL) of a solution of salt (about 0.5 μg of salt) was enough to induce a reproducible change in the electrical conductivity of polyaniline nano-network, which was registered as a function of time within 10–20 s. The response was proportional to the concentration of ions. It also depends on properties of ions, e.g., the ionic radius, which allows for identification of metal ions by analyzing the parameters of the signal: the retention time (RT), half width (HW), amplitude (A) and integral intensity (INT). The advantage of the new device is the instant responsiveness and easy operation, but also the simple construction based on organic (polymer) technology. The system is “open”—when learned and calibrated adequately, other metal ions can be analyzed. The nanodetector can be used in cases where monitoring of the presence and concentration of metal ions is important.

Revisiting the passivation of stainless steels and other passive CRAs

2018 ◽  
Vol 106 (1) ◽  
pp. 107 ◽  
Author(s):  
Jean- Louis Crolet
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Base Metal ◽  
Stainless Steels ◽  
Electronic Conductivity ◽  
Transport Processes ◽  
General Knowledge ◽  
Inorganic Polymers ◽  
Faraday Cage

All that was said so far about passivity and passivation was indeed based on electrochemical prejudgments, and all based on unverified postulates. However, due the authors’ fame and for lack of anything better, the great many contradictions were carefully ignored. However, when resuming from raw experimental facts and the present general knowledge, it now appears that passivation always begins by the precipitation of a metallic hydroxide gel. Therefore, all the protectiveness mechanisms already known for porous corrosion layers apply, so that this outstanding protectiveness is indeed governed by the chemistry of transport processes throughout the entrapped water. For Al type passivation, the base metal ions only have deep and complete electronic shells, which precludes any electronic conductivity. Then protectiveness can only arise from gel thickening and densification. For Fe type passivation, an incomplete shell of superficial 3d electrons allows an early metallic or semimetallic conductivity in the gel skeleton, at the onset of the very first perfectly ordered inorganic polymers (- MII-O-MIII-O-)n. Then all depends on the acquisition, maintenance or loss of a sufficient electrical conductivity in this Faraday cage. But for both types of passive layers, all the known features can be explained by the chemistry of transport processes, with neither exception nor contradiction.

A Highly Crystalline Anthracene-Based MOF-74 Series Featuring Electrical Conductivity and Luminescence

2019 ◽  
Author(s):  
Patricia Scheurle ◽  
Andre Mähringer ◽  
Andreas Jakowetz ◽  
Pouya Hosseini ◽  
Alexander Richter ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Light Emission ◽  
Block Design ◽  
High Surface ◽  
Visible Spectrum ◽  
Building Blocks ◽  
Divalent Metal Ions ◽  
Conductivity Enhancement ◽  
Surface Areas

Recently, a small group of metal-organic frameworks (MOFs) has been discovered featuring substantial charge transport properties and electrical conductivity, hence promising to broaden the scope of potential MOF applications in fields such as batteries, fuel cells and supercapacitors. In combination with light emission, electroactive MOFs are intriguing candidates for chemical sensing and optoelectronic applications. Here, we incorporated anthracene-based building blocks into the MOF-74 topology with five different divalent metal ions, that is, Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, resulting in a series of highly crystalline MOFs, coined ANMOF-74(M). This series of MOFs features substantial photoluminescence, with ANMOF-74(Zn) emitting across the whole visible spectrum. The materials moreover combine this photoluminescence with high surface areas and electrical conductivity. Compared to the original MOF-74 materials constructed from 2,5-dihydroxy terephthalic acid and the same metal ions Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, we observed a conductivity enhancement of up to six orders of magnitude. Our results point towards the importance of building block design and the careful choice of the embedded MOF topology for obtaining materials with desired properties such as photoluminescence and electrical conductivity.

scholarly journals Metallic surface doping of metal halide perovskites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuze Lin ◽  
Yuchuan Shao ◽  
Jun Dai ◽  
Tao Li ◽  
Ye Liu ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metallic Surface ◽  
Grand Challenge ◽  
New Device ◽  
Surface Doping ◽  
N Doping ◽  
Halide Perovskites ◽  
Heavily Doped ◽  
Low Solubility ◽  
Striking Contrast

AbstractIntentional doping is the core of semiconductor technologies to tune electrical and optical properties of semiconductors for electronic devices, however, it has shown to be a grand challenge for halide perovskites. Here, we show that some metal ions, such as silver, strontium, cerium ions, which exist in the precursors of halide perovskites as impurities, can n-dope the surface of perovskites from being intrinsic to metallic. The low solubility of these ions in halide perovskite crystals excludes the metal impurities to perovskite surfaces, leaving the interior of perovskite crystals intrinsic. Computation shows these metal ions introduce many electronic states close to the conduction band minimum of perovskites and induce n-doping, which is in striking contrast to passivating ions such as potassium and rubidium ion. The discovery of metallic surface doping of perovskites enables new device and material designs that combine the intrinsic interior and heavily doped surface of perovskites.

Structural and Electrical Properties of Titania Thin Films

2014 ◽  
Vol 925 ◽  
pp. 300-303 ◽  
Author(s):  
Sharipah Nadzirah ◽  
Uda Hashim ◽  
N. Malihah
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Titanium Dioxide ◽  
Current Flow ◽  
Sol Gel ◽  
Particle Sizes ◽  
Structural And Electrical Properties ◽  
Crystallite Sizes ◽  
Average Current ◽  
Flow Through

This research studies the properties of titanium dioxide (TiO2) nanoparticles synthesized by two different stabilizers via sol-gel method. Acetic and hydrochloric acids have been used as stabilizers to form two different TiO2 thin films. 100 μm gap of Al IDEs have been fabricated on each annealed TiO2 films. Finally the samples were physically and electrically characterized. Average crystallite sizes of the nanoparticles are 20 and 25 nm for acetic and hydrochloric acid respectively. The average current flow through the devices was extremely small which are around micro-to-nanoampere. It was found that the electrical conductivity increased significantly when particle sizes decreases.

scholarly journals Specialties of the structure and conductivity of the non-aqueous electrolytes based on alkali metal bis (salicyl) borates and bis (oxalate) borates

2019 ◽  
Vol 85 (3) ◽  
pp. 49-55
Author(s):  
Viktor Diamant ◽  
Volodymyr Trachevskii ◽  
Katherine Pershina ◽  
Volodymyr Ogenko ◽  
Chen Donchu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Alkali Metals ◽  
Electrochemical Impedance ◽  
Integral Intensity ◽  
Low Frequency ◽  
Aqueous Electrolytes ◽  
Thermal Dependence ◽  
Spectra Analysis ◽  
Reactive Medium ◽  
Coordination Environment

The structure and coordination environment of non-aqueous electrolytes based on bis(salicyl)borates of lithium, sodium, potassium, tetramethylammonium (MeBSB) and bis(oxalato)borates from lithium to cesium (MeBOB) using NMR spectroscopy have been investigated. Bis(salicyl)borates (BSB) and bis(oxalate)borates (BOB) of alkali metals and organic cations are considered as promising electroconductive components of electrolytes of modern chemical sources of current (lithium, sodium ion batteries and super-capacitors). The salts were synthesized by the microwave radiation method. The 13C and 11B NMR spectra analysis determined the presence of symmetric structure in BOB anion and the presence of two optical conformations of the BSB anion with labile coordination environment of boron. The conformations of the BSB are the result of the ion contact pairs formation. In the case of tetramethylammonium cation the presence of conformations are depended on the reactive medium. The conformational lability of the coordination sphere of NaBSB dissolved in DMAA is connected with increasing of the integral intensity of carboxyl group singles relatively signals of carbon atoms in fragments of another functional affiliation when the time delay between radio frequencies varies within 2-15 seconds. The difference in the structure of these anions leads to a change in the thermal dependence of the electrical conductivity of BSB and the transport of ions in non-aqueous solvents. Maximum electrical conductivity of salt solutions in DMFA is achieved at close concentrations of 0.75 m for KBSB and 0.77-1 m for NaBSB. The solubility of BSB is better than the BOB. Based on the measurements of the conductivity and the data of electrochemical impedance spectroscopy (the angle of inclination of spectra in the Nyquist coordinates in the low frequency range, the phase angle shift at a frequency) it was proposed the existence of two ways of ions and charge transfer in the electrolytes: diffusion and relay transport. The possibility of formation of a labile salt complex with a solvent due to hydrogen bonds is established.  

A highly crystalline anthracene-based MOF-74 series featuring electrical conductivity and luminescence

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20949-20955 ◽  
Author(s):  
Patricia I. Scheurle ◽  
Andre Mähringer ◽  
Andreas C. Jakowetz ◽  
Pouya Hosseini ◽  
Alexander F. Richter ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Building Block ◽  
High Surface ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Surface Areas

A novel highly crystalline MOF-74 series consisting of an anthracene-based building block and five different divalent metal ions is presented. The MOFs combine photoluminescence with high surface areas and electrical conductivity.

Two isostructural linear coordination polymers: the size of the metal ion impacts the electrical conductivity

2018 ◽  
Vol 42 (12) ◽  
pp. 10309-10316 ◽  
Author(s):  
Basudeb Dutta ◽  
Arka Dey ◽  
Kaushik Naskar ◽  
Suvendu Maity ◽  
Faruk Ahmed ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Linear Coordination

Electrical conductivity was tuned by altering the metal ions in acetylenedicarboxylate (adc) and 4-styrylpyridine (4-spy)-based 1D coordination polymers, {[M(adc)(4-spy)2(H2O)2]}n (M = Zn and Cd).

The effect of nitric acid (HNO3) treatment on the electrical conductivity and stability of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) thin films

2017 ◽  
Vol 37 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Suhana Mohd Said ◽  
Shahriar Mufid Rahman ◽  
Bui Duc Long ◽  
Subramanian Balamurugan ◽  
Norhayati Soin ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Nitric Acid ◽  
Acid Treatment ◽  
Base Material ◽  
Operating Conditions ◽  
Organic Polymer ◽  
Visible Range ◽  
Infrared Analysis ◽  
Conductivity Enhancement ◽  
Improved Stability

Abstract In this work, the posttreatment of an organic polymer is performed using an inorganic acid, nitric acid (HNO3). We picked poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the base material and improved its electrical conductivity by acid treatment with different concentrations of HNO3. The acid treatment was able to achieve the optimum electrical conductivity of 197 S/cm, which is 115.5 times higher than the base material when treated with an aqueous solution containing 65% of HNO3. Moreover, the films showed higher transparency in the visible range while conducting Fourier transform infrared analysis. In addition, the treated films showed improved stability against outdoor operating conditions in terms of sheet resistance compared with untreated PEDOT:PSS films. We tried to develop a hypothesis to describe the reason behind the electrical conductivity enhancement by studying the thicknesses of all the samples at different acid concentration levels. The results from atomic force microscopy, the Hall effect, and the trend of film thickness suggest that the conformational change, the removal of excess PSS from the polymer, and the increase in carrier concentration are the reasons behind the improvement in electrical conductivity.

scholarly journals Absorbed Pb2+ and Cd2+ Ions in Water by Cross-Linked Starch Xanthate

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Kai Feng ◽  
Guohua Wen
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Adsorption Mechanism ◽  
Potato Starch ◽  
Sodium Acrylate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Concentration Of Ions ◽  
Cross Linker

A cross-linked starch xanthate was prepared by graft copolymerization of acrylamide and sodium acrylate onto starch xanthate using potassium persulfate and sodium hydrogen sulfite initiating system and N,N′-methylenebisacrylamide as a cross-linker. As this kind of cross-linked potato starch xanthate can effectively absorb heavy metal ions, it was dispersed in aqueous solutions of divalent heavy metal ions (Pb2+ and Cd2+) to investigate their absorbency by the polymer. Factors that can influence absorbency were investigated, such as the ratio of matrix to monomers, the amount of initiator and cross-linker, pH, and the concentration of metal ions. Results were reached and conclusion was drawn that the best synthetic conditions for the polymer adsorbing Pb2+ and Cd2+ were as follows: the quality ratio of matrix to monomers was 1 : 12 and 1 : 11, the amount of initiator was 2.4% and 3.2% of matrix, and the amount of cross-linker was 12 mg and 13 mg. When the initial concentration of ions was 10 mg/L, the highest quantities of adsorption of Pb2+ and Cd2+ were 47.11 mg/g and 36.55 mg/g. Adsorption mechanism was discussed by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) test, and adsorption kinetic simulation.

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