Conducting polymer interaction with gaseous substances I. Water

Timofeeva, O.N.; Lubentsov, B.Z.; Sudakova, Ye.Z.; Chernyshov, D.N.; Khidekel, M. L.

doi:10.1016/0379-6779(91)91493-t

Cited by 53 publications

(10 citation statements)

References 8 publications

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“…In the presence of water, the polyaniline conductivity increases by ten times (see, e.g., Ref. 22 and references cited therein). The influ ence of water on the conductivity is explained in different manners.…”

Section: Resultsmentioning

confidence: 97%

“…The influ ence of water on the conductivity is explained in different manners. According to available data, 22 water forms bridges between the polyaniline chains; it is also assumed 23 that segmental motions of the polyaniline chains are intensi fied in the presence of water due to the hydrogen bond cleavage. 24 The χT-T plot for the PAN 1 powder is presented in Fig.…”

Section: Resultsmentioning

confidence: 99%

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On the triplet nature of paramagnetic centers in conducting polymers

et al. 2008

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Temperature dependences of the magnetic susceptibility of solutions and powders of polyaniline synthesized by oxidative polymerization using two methods were measured by ESR in the temperature range from 123 to 423 K. The dependences observed can be described by the integral of susceptibility of the polymer fragments in the triplet state over the singlet-triplet splitting from E 1 to E 2 with constant weight. The susceptibility of the fragments was accepted to obey the Bleaney-Bowers equation. The most part of the experimental dependences can be presented as the sum of the temperature independent susceptibility and the susceptibility obeying the Curie law. The both susceptibilities are described in a single manner at E 1 < 0. In some cases, the comparison of the calculated and experimental dependences makes it possible to determine the length of the fragments L. The conditions of polymer synthesis, heating, and water vapors affect the E 1 and E 2 values. A similar analysis can be applied to other conducting polymers. , and many other, are interesting due to their unusual physical prop erties and a possibility of their diverse practical use. From this point of view, the most attention was given to studies of luminescence and conductivity. Magnetic properties are of a special interest, being tightly related to the nature of charge carriers and to fine features of the polymer structure.The frequently observed experimental linear temperature dependence of the product of the magnetic susceptibility by the temperaturemakes it possible to divide the susceptibility into two com ponents: the temperature independent part χ P and the part obeying the Curie law χ = C/T (see, e.g., data for polyaniline, 1-3 polythiophene, 3 and polypyrrole 4 ). The origin of these two components is usually explained in terms of the "metallic" model, according to which pow ders and films of doped conducting polymers are highly ordered metallic regions immersed into amorphous re gions (see, e.g., Refs 1-3 and references cited therein). Paramagnetism and conductivity of conducting polymers are considered to appear after doping, i.e., when charges and unpaired electrons are formed in the polymers. Due to the spatial periodicity of the metallic regions, the energy spectrum of electrons has a zone character. The upper zone is partially filled, resulting in the appearance of such properties as high electron conductivity and the temperature independent Pauli susceptibility. Distortions in the lattice periodicity induce a minor number of local ized electrons, viz., polarons with the spin 1/2, whose susceptibility obeys the Curie law. However, some experimental facts does not obey this scheme. It is natural to expect that the ESR lines of the localized spins and metallic regions have different widths but, in the most cases, the ESR lines of the conducting polymers exhibit no superposition of the lines with differ ent widths. As a rule, the shape of the ESR lines in the line center is close to the Lorentzian one, and the descent on the wings is faster. ...

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

On the triplet nature of paramagnetic centers in conducting polymers

et al. 2008

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“…It is known that water increases the electrical conductivity of polyaniline through an increase in the interchain electron transfer [15][16][17][18] and/or by increasing the mobility of dopant ions [19]. Conductivity increases of several orders of magnitude in the presence of water have been recorded with linear and reversible responses [18][19][20].…”

Section: Introductionmentioning

confidence: 97%

Micro-humidity sensors based on a processable polyaniline blend

McGovern

Spinks

Wallace

2005

Sensors and Actuators B: Chemical

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“…It is known that water increases the electrical conductivity of polyaniline through an increase in the interchain electron transfer [20][21][22][23] and / or by increasing the mobility of dopant ions [24] . Conductivity increases of several orders of magnitude in the presence of water have been recorded with linear and reversible responses [23][24][25] .…”

Section: Introductionmentioning

confidence: 99%

Highly processable method for the construction of miniature conducting polymer moisture sensors

McGovern

Spinks

Wallace

2005

Smart Structures, Devices, and Systems II

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A polymer blend incorporating polyaniline (PAn) was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised to PAn emeraldine salt (ES) in the presence of poly (butyl acrylate-co-vinyl acetate) and the processable blend was developed by redissolving 1-2 w/w% of the resulting sensing polymer residue in dichloromethane (DCM). Some of this residue was washed in ammonia solution to de-dope the PAn to emeraldine base (EB) to act as a protective layer on the surface of the sensing polymer. This residue was then washed with distilled water until a neutral pH was realised with the waste water, dried and redissolved in DCM at 1-2 w/w% to create a processable blend barrier polymer solution. The final sensor design utilised 125µm polyester insulated platinum wire as conducting electrodes that were dip coated in the PAn ES blend solution and dried in a desiccator. A protective coating was then applied by dip coating in the EB blend solution. The sensors had an overall final thickness of less than 200µm and showed high sensitivity to humidity, low resistance, and good reversibility without hysteresis. The EB protective layer was shown to give more stable and predictable responses to the sensors when placed inside curing epoxies. Polymer based thin film humidity sensors have the advantage that the high processability of the material allows for simple fabrication of a range of geometries including smaller sensor designs. Such sensors may find uses in detecting water content in a number of areas including composite materials, electronic textiles, food/ electronics packaging and corrosion detection.

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Conducting polymer interaction with gaseous substances I. Water

Cited by 53 publications

References 8 publications

On the triplet nature of paramagnetic centers in conducting polymers

On the triplet nature of paramagnetic centers in conducting polymers

Micro-humidity sensors based on a processable polyaniline blend

Highly processable method for the construction of miniature conducting polymer moisture sensors

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