Wyniki wyszukiwania - Biblioteka Nauki

1

Bronsted versus lewis acid doping of polyaniline

100%

Kulszewicz-Bajer I.

Prace Naukowe Politechniki Warszawskiej. Chemia

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2000

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tom z. 65

3-70

EN

The presented research is devoted to the elucidation of new polyaniline doping systems which improve the processibility of this polymer. Special emphasis was put on spectroscopic investigations of dopant - solvent - polymer interactions and their influence on supramolecular structure and, as a consequence, on the electrical transport properties of the solution processed polymer. Two types of doping were studied: - protonation with Brónsted acids, - complexation with Lewis acids. It should be noted that the latter type of doping was introduced for the first time by the author of this dissertation. In particular, it is demonstrated that the protonation of polyaniline with sulfonic or phosphonic acids in perfluorinated alcohols or dichloroacetic acid led to the formation of highly conducting polymer films. The processing of polyaniline from solvents of acidic character and H-bonding formation capability favors the delocalization of charge carriers along the polymer chains. Systematic spectroscopic studies of mutual interactions between all three components of the processing system allows for the selection of appropriate dopant - solvent couples. The best results were obtained for poyaniline films cast from a camphorsulfonic acid - hexafluoro-2-propanol system, which showed metallic type of conductivity down to 200 K. The study of polyaniline doping with Brónsted acids of polymeric nature, namely poly(alkylene phosphates), was also undertaken. In these cases stable solutions of polyaniline protonated with polyphosphates were obtained in N-methylpyrrolidinone or m-cresol. The detailed spectroscopic studies showed that the protonation level was Iower than corresponding molar ratio of both polymers. The decrease of the length of alkylene spacer of polyphosphates promotes the protonation. Blends of polyaniline protonated with poly(alkylene phosphates) with poly(methyl methacrylate) were also prepared. The addition of a plasticizer such as dibutyl phthalate improves the conductivity of the blend and Iowers the percolation threshold. The percolation threshold decreases with the increase of the length of alkylene spacer, whereas the resistance against deprotonation in basic solutions decreases in the inverse order. The newly discovered Lewis acid doping of polyaniline which is discussed in the last part of the dissertation also improves solution processibility of this polymer. Polyaniline complexed with FeCl3, AlCl3, GaCl3, SnCl4 is soluble in nitromethane or acetonitrile, i. e. solvents which dissolve neither the base nor protonated form of PANI. Free standing films can be cast from these solutions. The complexation proceeds on amine as well as on imine sites of polyaniline. The doping is reversible and is purely acid-base in nature. This last discovery opens up new possibilities of polyaniline modification by the consecutive application of Brónsted and Lewis dopants.

PL

Przedstawiona praca poświęcona jest badaniu nowych układów domieszkujących polianilinę, ułatwiających przetwarzanie polimeru. Szczególną uwagę zwrócono na badania spektroskopowe oddziaływań między domieszką, rozpuszczalnikiem i polimerem oraz ich wpływem na strukturę nadcząsteczkową, a w konsekwencji na własności elektryczne polimeru przetwarzanego z roztworu. Były badane dwa rodzaje domieszkowania: - protonowania kwasami Brónsteda, - kompleksowanie kwasami Lewisa. Należy zaznaczyć, że drugi rodzaj domieszkowania został po raz pierwszy zastosowany przez autora pracy. W szczególności wykazano, że protonowanie polianiliny kwasami sulfonowymi lub fosfo-niowymi w alkoholach perfluorowanych lub kwasie dichlorooctowym prowadzi do powstania warstw wysokoprzewodzącego polimeru. Przetwarzanie polianiliny z rozpuszczalników o charakterze kwasowym, ze zdolnością tworzenia wiązań wodorowych, ułatwia delokalizację nośników ładunku wzdłuż łańcuchów polimeru. Systematyczne badania spektroskopowe wzajemnych oddziaływań pomiędzy wszystkimi trzema składnikami układu pozwalają wybrać odpowiednią parę domieszka-rozpuszczalnik. Najlepsze wyniki uzyskano w przypadku warstw polianiliny domieszkowanej kwasem kamforosulfonowym w heksafluoro-2-propanolu, które wykazywały przewodnictwo elektryczne typu metalicznego do 200 K. Zostały podjęte badania domieszkowania polianiliny polimerowymi kwasami Brónsteda, mianowicie poli(alkilenofosforanami). Otrzymano polianilinę protonowaną polifosforanami rozpuszczalną w N-metylopirolidonie lub m-krezolu. Szczegółowe badania spektroskopowe wykazały, że stopień protonowania był niższy niż odpowiedni stosunek molowy obu polimerów. Zmniejszenie długości łańcucha łącznika alkilenowego polifosforanów ułatwia protonowanie. Otrzymano również blendy polianiliny protonowanej poli(alkilenofosforanami) z poli(metakrylanem metylu). Dodanie plastyfikatora takiego jak ftalan dibutylu zwiększa przewodnictwo blend i obniża próg perkolacji. Próg perkolacji zmniejsza się wraz ze wzrostem długości łącznika alkilenowego, podczas gdy odporność na deprotonowanie w roztworach zasadowych zmniejsza się w odwrotnym porządku. Domieszkowanie polianiliny kwasami Lewisa, omawiane w ostatniej części pracy, również poprawia przetwarzanie tego polimeru z roztworu. Polianilina kompleksowana FeCI3, AlCI3, GaCI3 lub SnCl4 jest rozpuszczalna w nitrometanie lub acetonitrylu, tj. w rozpuszczalnikach, które nie rozpuszczają PANI ani w formie zasadowej, ani protonowanej. Cienkie warstwy polimeru mogą być wylewane z omawianych roztworów. W kompleksowaniu uczestniczą zarówno centra aminowe jak i iminowe polianiliny. Proces domieszkowania jest odwracalny i ma charakter reakcji kwasowo-zasadowej. Ostatnie badania otwierają nowe możliwości modyfikacji własności polianiliny poprzez połączenie reakcji protonowania i kompleksowania.

2

Complexation of polyaniline with Lewis acids - a Mössbauer spectroscopy study

80%

Bieńkowski K. , Oddou J. , Horner O. , Kulszewicz-Bajer I. , Genoud F. , Suwalski J. , Pron A.

Nukleonika

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2003

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tom Vol. 48,suppl.1

3-7

EN

Doping with Lewis acid is a new method for improving solution processibility of conductive polyaniline. We report here detailed Mössbauer spectroscopy studies of polyaniline complexed with Lewis acids containing Mössbauer active nuclei, namely SnCl4 and FeCl3. Films of Lewis acid doped polyaniline cast from nitromethane solutions show stoichiometries of PANI(MeCln)1(CH3NO2)1 (where n = 3 or 4, Me denotes Sn or Fe and PANI denotes one aniline repeat unit), which means that both types of polyaniline nitrogens (imine and amine) participate in the complexation reaction, and one solvent molecule is introduced in the polymer matrix per one Lewis acid molecule. Mössbauer parameters of polyaniline doped with SnCl4 are consistent with hexacoordinated Sn(IV) in an environment of non-equivalent ligands. The spectrum of PANI doped with FeCl3 consists of two doublets with distinctly different Mössbauer parameters, which can be ascribed to two types of complexing sites (amine and imine nitrogens). From the temperature dependence of the isomer shift and the recoil free absorption, we have calculated the Mössbauer lattice temperature, ?m, as probed by both complexing sites, which are 83 K for amine and 126 K for imine sites.

3

Determination of ascorbic acid using differential pulse voltammetry method on aniline-co-para–aminophenol modified electrode

80%

Parsa A. , Tajik M.

Polish Journal of Chemical Technology

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2017

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tom Vol. 19, nr 2

125--129

EN

The electro-synthesis of poly(aniline-co-para–aminophenol) on graphite electrode was examined using cyclic voltammetry (CV) over the potential window of −0.2 V to 1 V in phosphoric acid medium, which was comprised of potassium chloride and para–Toluene sulfonic acid (pTSA) as electrolyte support. Fourier transform infrared (FTIR) spectroscopy was employed to identify the electro-synthesized copolymer while impedance techniques were used to determine charge transfer resistance (Rct) in modified and unmodified electrodes. After this, the electro-catalytic effect of the modified electrode on ascorbic acid was examined using differential pulse voltammetry (DPV) and a very strong response was observed. A negative shift of about 0.33 V was found in the peak anodic potentials for ascorbic acid. Measurement using DPV indicated a proper response by the electrode to a wide range of ascorbic acid concentrations, from 0.0001 to 0.0004 M. The peak anodic currents for increased concentrations showed a proper linear range.

4

Laser induced forward transfer of conducting polymers

80%

Kandyla M. , Chatzandroulis S. , Zergioti I.

Opto-Electronics Review

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2010

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tom Vol. 18, No. 4

345-365

EN

We report on laser printing of conducting polymers directly from the solid phase. Laser induced forward transfer is employed to deposit P3HT:PCBM films on glass/ITO/PEDOT:PSS substrates. P3HT:PCBM is widely used as the active material in organic solar cells. Polyaniline films, which are also printed by laser induced forward transfer, find many applications in the field of biotechnology. Laser printing parameters are optimized and results are presented. To apply solid-phase laser printing, P3HT:PCBM films are spun cast on quartz substrates, while aniline is in-situ polymerized on quartz substrates.

5

Modeling of the crystalline structure of the complex system containing doped polyaniline by use of genetic algorithms

80%

Kozik T. , Luzny W.

Journal of Education and Technical Sciences

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2015

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tom Vol. 2, nr 1

9--14

EN

The structure of polyaniline (PANI) protonated with camphorsulphonic acid (CSA) has been subject to research for a long time. Despite several, various models being proposed throughout the years, there is still no model widely accepted as the only correct and final one of its crystalline phase. In this paper a computer program named MoleculeEditor is described. Created basing on the concepts of an existing but significantly different program named CrystalFinder, it is a software dedicated to finding a model of the crystalline regions of the PANI/CSA system based on an input X-ray diffraction pattern. In its search it takes advantage of the genetic algorithm technique for optimizing the model parameters to fit the computed diffraction pattern to the one loaded as input. A successful example of it being employed to find the parameters of a prepared beforehand, fictional structure of the system, is presented. Conclusions drawn from this application of the prepared software cannot be ignored in the further search for the actual model of this complex system using this program. Obtaining results from MoleculeEditor for actual, experimental data is however still in progress.

6

Double-layer microwave absorber based on nanocrystalline CoFe2O4 and CoFe2O4/PANI multi-core/shell composites

80%

Xu Y. , Shen G. , Wu H. , Liu B. , Fang X. , Zhang D. , Zhu J.

Materials Science Poland

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2017

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tom Vol. 35, No. 1

94--104

EN

Organic-inorganic nano-CoFe2O4/PANI (polyaniline) multi-core/shell composites have been successfully synthesized by chemical oxidative polymerization of aniline. The characterization results showed that the ferrite nanocrystals were efficiently embedded in PANI. The electromagnetic parameters of the composites were measured by a vector network analyser in the frequency range of 2 GHz to 18 GHz. Double-layer absorbers based on the CoFe2O4/PANI composite (matching layer) and calcined CoFe2O4 ferrite (absorbing layer) have been designed. The reflection loss of the microwave absorbers of both single layer and double-layer with a total thickness of 2.0 mm and 2.5 mm was calculated according to transmission-line theory. The results indicated that the minimum reflection loss of the CoFe2O4/PANI composite was −19.0 dB at 16.2 GHz at the thickness of 2.0 mm and −23.6 dB at 13.1 GHz at the thickness of 2.5 mm, respectively. The minimum reflection loss for double-layer absorbers reached −28.8 dB at 16.2 GHz at the total thickness of 2.0 mm, and −31.1 dB at 12.8 GHz at the total thickness of 2.5 mm. The absorption bandwidth under −10 dB was 4.2 GHz (13.8 GHz to 18.0 GHz) and 5.5 GHz (10.3 GHz to 15.8 GHz), respectively. The results show that the reflection loss and absorption bandwidth of the double-layer absorbers are obviously enhanced compared to corresponding single layer absorbers.

7

Preparation of polyaniline nanostructures doped with different dicarboxylic acids through template-free method

80%

Sun C. , Wang Y.

Materials Science Poland

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2014

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tom Vol. 32, No. 3

419—422

EN

Department of Materials Chemistry, Yinuo Institution, Changchun, 130033, China In this article nanoscaled polyanilines (PANI) were prepared based on template-free method in the presence of dicarboxylic acid dopants (e.g. D-tartaric acid, succinic acid, maleic acid and fumaric acid). The trans-cis isomerization of butenedioic acid played an important role in the formation of nanostructures from the plane-like to nanofibers, and the PANI doped with maleic acid (MA) had larger diameter, higher crystallinity and conductivity than PANI doped with fumaric acid (FA).

8

Polyaniline-polypyrrole coating for solid phase microextraction

80%

Vickackaite V. , Ciuvasovaite V.

Open Chemistry

|

2007

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tom 5

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nr 3

727-738

EN

A procedure for direct electrochemical deposition of polyaniline-polypyrrole blend coating on the surface of stainless steel wire was suggested. Incorporation of polyaniline and polypyrrole into the blend coating was confirmed by infrared spectroscopy. Key parameters (pyrrole, aniline, dopant and sulphuric acid concentrations and deposition potential) influencing the coating’s mechanical stability and surface homogeneity were optimised and thermostability of the coating was investigated. A possibility to apply the coating as a new fibre for solid phase microextraction was demonstrated. The coating showed better selectivity toward aromatic, hydrophobic compounds. [...]

9

Zeta potential and doping in polyaniline dispersions

80%

de Medeiros D. W. O. , dos Santos D. S. , Dantas T. N. C. , Pereir M. R. , Giacometti A. , Fonseca J. L. C.

Materials Science

|

2003

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tom Vol. 21, No. 2

251-257

EN

Polyaniline (PAni) has been classified as an intractable polymer, particularly in its conducting form, the emeraldine salt (ES). Therefore one can consider the mixture of water and PAni as a suspension. The conducting form of PAni can be obtained by a doping process known as ,,acid doping'', in which a strong acid turns PAni from its insulating form, the emeraldine base (EB), into the conducting form, the emeraldine salt. With the objective of establishing a correlation between the doping level and the zeta potential of polyaniline dispersions, polyaniline +HCl aqueous suspensions were prepared. Positive zeta potential values for the various suspensions of PAni showed that it acquired positive charges after the doping process. It was also observed an increase in zeta potential values as HCl concentration increased, which could be correlated to UV-Vis spectra of PAni suspensions.

10

ESR spectroelectrochemistry studies of polyaniline's redox reactions

80%

Palka G. , Domagała W. , Duber S. , Łapkowski M.

Zeszyty Naukowe. Chemia / Politechnika Śląska

|

2001

|

tom z. 146

303-306

PL

W pracy przedstawiono wyniki badań spektroelektrochemicznych polianiliny z wykorzystaniem spektroskopii elektronowego rezonansu paramagnetycznego (EPR). Badano zmiany własności paramagnetycznych polianiliny towarzyszących jej elektrochemicznemu utlenianiu i redukcji. Syntezę polimeru przeprowadzono metodą woltamperometrii cyklicznej w środowisku wodnego roztworu HCl. Pod wpływem przyłożonego potencjału film polianilinowy drastycznie zmienia swoje przewodnictwo elektryczne przechodząc od izolatora do przewodnika. Zmiana ta wywoływana jest zachodzącymi procesami redoks, którym towarzyszą zmiany w strukturze chemicznej polimeru. W pracy określono charakter nośników ładunku, jakie pojawiają się w przewodzącym polimerze oraz zbadano ich zachowanie się pod wpływem przyłożonego potencjału. Na podstawie otrzymanych wyników dokonano oceny możliwości pracy spektrometru EPR w sprzężeniu z elektrochemicznym zestawem pomiarowym pod kątem prowadzenia badań spektroelektrochemicznych in situ.

11

Fabrication of MWNTs-PANI composite - a chemiresistive sensor material for the detection of explosive gases

80%

Yuan C. L. , Chang C. P. , Hong Y. S. , Sung Y.

Materials Science Poland

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2009

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tom Vol. 27, No. 2

509--520

EN

A chemiresistive sensor was fabricated by the chemical modification of multi-walled carbon nanotubes (MWNTs) and chemical oxidation of polyaniline (PANI). The resistances of the sensing film samples against 100, 250, 500, 1000 ppm explosives (picric acid (PA), 2,6-dinitrotoluene (2,6-DNT) and 2,4,6-trinitrotoluene(TNT)) agents were investigated. The MWNTs with various wt. % PANI agents were characterized by TGA, SEM, FTIR and Raman spectroscopy, respectively. The experimental results showed that 1wt. % MWNTs and 10, 5, 1wt. % PANI sensor samples provided high sensitivity, excellent selectivity and good reproducibility to PA and 2,6-DNT vapours. In addition, principal component analysis (PCA) was applied to distinguish the performance of PA, 2,6-DNT and TNT agents. Our results indicate that the electric detection of explosive agents is possible with simply fabricated MWNTs-PANI devices.

12

Formation of thin polyaniline films by means of ionic sputtering in crossed electromagnetic field

80%

Hotra Z. , Stakhira P. , Shandra Z. , Cherpak V. , Kremer I. , Volynyuk D. , Skoczylas M.

Elektronika : konstrukcje, technologie, zastosowania

|

2008

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tom Vol. 49, nr 6

184-185

EN

The technological condition for polyaniline thin films deposition by me ans of ionic sputtering in argon atmosphere is considered. As result polyaniline films of conductive emeraldine form was obtained.

PL

W artykule przeanalizowano uwarunkowania technologiczne osadzania cienkich warstw polianiliny metodą rozpylania jonowego. W rezultacie otrzymano warstwy polianiliny w postaci przewodzącej emeraldyny.

13

Chemical Polymerisation of Aniline in the Presence of Sericin

80%

Kaitsuka Y. , Goto H.

International Letters of Chemistry, Physics and Astronomy

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2015

|

tom Vol. 46

48--53

EN

A series of polyaniline/sericin composites were prepared by oxidative polymerisation of aniline in the presence of sericin. The preparation of polyaniline composites containing sericin were confirmed by Fourier-transform infrared spectroscopy. From the result of electron spin resonance spectroscopy, the electron spin concentration of the composites decreases with sericin/aniline ratio in the polymerisation. Circular dichroism absorption spectroscopy measurements revealed that sericin influences aggregation state of polyaniline. Scanning electron microscopy suggested that the polyaniline composites show granular morphology. The composites display macroporous structure after carbonization.

14

Polyaniline-multi-walled carbon nanotube shell-core composite as an electrode material in supercapacitors

80%

Zawadzka E. , Kuliński R. , Szubzda B. , Mazurek B.

Materials Science Poland

|

2009

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tom Vol. 27, No. 4/2

1271--1278

EN

Polyaniline-multi-walled carbon nanotubes (PANI/MWCNTs) composite has been synthesized by in situ oxidizing polymerization of aniline in water dispersion of MWCNTs and has been tested as a supercapacitor electrode material. Supercapacitive behaviour of the shell core composite has been investigated by a cyclic voltammetry and galvanostatic charge-discharge tests. In order to obtain information about the composite composition additional thermoanalytical tests have been carried out including mass decrement and heat stream in function of temperature. The research is aimed at utilization of the specific structure of the shell core composite type for designing new materials with promising properties which could find application as supercapacitor electrode materials.

15

Electrochemical biosensors based on polyaniline

80%

Wei D. , Ivaska A.

Chemia Analityczna

|

2006

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tom Vol. 51, No. 6

839-852

EN

Electrochemical biosensors based on conducting polymers offer many advantages and new possibilities to detect biologically significant compounds. Various biosensors, such as enzyme sensors, DNA sensors and immunosensors based on polyaniline are reviewed in this paper. Besides electrochemical detection methods, some new trends with the combination of other techniques are also shortly discussed.

PL

Biosensory elektrochemiczne z zastosowaniem polimerów przewodzących oferują liczne zalety i wiele nowych możliwości w oznaczaniu związków o dużym znaczeniu biologicznym. W niniejszym artykule przedstawiono przegląd sensorów enzymatycznych, DNA oraz immunosensorów, stworzonych z użyciem polianiliny. Poza elektrochemicznymi metodami analizy, przedyskutowano również nowe kierunki wykorzystania innych technik analitycznych.

16

Preparation of network π-conjugated copolymers with Ullmann type polycondensation

80%

Nakajima K. , Goto H.

International Letters of Chemistry, Physics and Astronomy

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2014

|

tom Vol. 6

33--38

EN

Ullmann type polycondensations in the presence of CuI and a base were carried out to afford network type π-conjugated copolymers. Infrared absorption spectroscopy measurements and surface observation using a scanning electron microscopy are carried out. Electron spin resonance spectroscopy measurements revealed that the cross-linked copolymers thus obtained contain small amount of copper. This polymerization conveniently allows production of network π-conjugated polymers. The polymer can be expected to have thermo-resistance.

17

PANI/NaTaO3 composite photocatalyst for enhanced hydrogen generation under UV light irradiation

80%

Zielińska B. , Schmidt B. , Mijowska E. , Kaleńczuk R.

Polish Journal of Chemical Technology

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2017

|

tom Vol. 19, nr 3

115--119

EN

A PANI/NaTaO3 composite was successfully synthesized by an oxidative polymerization of aniline monomer in hydrochloric acid solution containing sodium tantalate. NaTaO3 at a monoclinic structure was produced via hydrothermal method. The photocatalytic activities of the unmodified NaTaO3 and PANI/NaTaO3 were evaluated for hydrogen generation from an aqueous HCOOH solution and under UV light irradiation. The results showed that the evolution rate of H2 increased significantly when NaTaO3 was modified with PANI. The enhancement of the photocatalytic activity of PANI/NaTaO3 composite was ascribed to the effective charge transfer and separation between NaTaO3 and PANI, which reduced their recombination. This indicates that PANI modification of tantalate photocatalysts may open up a new way to prepare highly efficient catalytic materials for H2 generation.

18

An ammonia sensor based on in situ-synthesized polyaniline nanostructures

80%

Dobroczyńska J. I. , Grabas K.

Materials Science Poland

|

2013

|

tom Vol. 31, No. 1

95--100

EN

Nowadays, a good deal of research is focusing on the development of new analytical procedures for detection of hazardous agents, such as bacteria, harmful pollutants, toxic vapors, and many others. The majority of the research is aimed at developing new sensors and analytical equipment. This paper demonstrates a simple construction of an ammonia sensor based on commercially available electronic connectors with active elements from polyaniline. The main goal of this research is to present the simplicity of sensor manufacturing, without the need for advanced apparatus such as electropolymerization or electrospinning set-up. The active element of the proposed sensor is composed of polyaniline synthesized in situ on the surface of conductive glue. The layer of the conductive glue is a key element in this sensor as it protects the metallic pin against destruction during in situ synthesis of polyaniline (acidic and oxidizing conditions).

19

Electrical Conductivity and Morphology Study of Polyaniline Powder Synthesised with Various Doping Ions

80%

Golba S. , Popczyk M. , Miga S. , Jurek-Suliga J. , Zubko M.

Archives of Metallurgy and Materials

|

2019

|

tom Vol. 64, iss. 3

1023--1028

EN

Powdered polyaniline (PANI) was synthesised chemically with different doping anions namely hydrochloric acid, sulphuric acid and para-toluenesulfonic acid (pTSA). Two-step synthetic procedure was utilised at low temperature. The highest reaction efficiency was found for chlorine-doped PANI. Structural characterization with FTIR revealed the vibration bands characteristicto formation of the emeraldine salt. The surface morphology of doped PANIs was studied by SEM images which showed near globular shape and porous structures with different size of the aggregated particles. They were smaller for Cl-- or pTS--doped PANI while for SO4 2- the size was markedly larger. The XRD patterns revealed that there are ordered regions especially for pTS- doped PANI, while the highest conductivity value was recorded for Cl- doped one followed by organic pTS- doped and SO4 2- doped one.

20

Cultivation of paramecium caudatum in the presence of physiologically active substances, and a redox active polymer

80%

Goto H. , Nakajima K.

International Letters of Chemistry, Physics and Astronomy

|

2015

|

tom Vol. 46

26--29

EN

Cultivation of paramecium in the presence of physiologically active substances was carried out. We have monitored paramecium for 23 days in the solutions in the presence of physiologically active substances, and polyaniline as a redox active polymer.