D. c. conductivity

In a pulse-radiolysis d.c. conductivity method, is measured and then is determined from the measured kj and a separately known In a pulse-radiolysis charge-clearing method, a residual amount of charge that is left unrecombined is collected and measured. Because the collected charge is expressed as a function of k, the value of where is a correction factor due... 

In a pulse-radiolysis d.c. conductivity method with a long pulse width, the resulting steady state current during the long pulse is considered by the assumption that the rate of excess electron generation becomes equal to the rate of electron loss because of the reaction with positive ions and impurities. 

Due to the fact that there is no accurate technique valid for the entire curing reaction, two techniques should be used to follow cure one applied to before gelation (DSC) and another one applied after gelation (TBA, DMA, TMA, d.c. conductivity [50,128,174,175]). 

Bulk crystalline radical ion salts and electron donor-electron acceptor charge transfer complexes have been shown to have room temperature d.c. conductivities up to 500 Scm-1 [457, 720, 721]. Tetrathiafiilvalene (TTF), tetraselenoful-valene (TST), and bis-ethyldithiotetrathiafulvalene (BEDT-TTF) have been the most commonly used electron donors, while tetracyano p-quinodimethane (TCNQ) and nickel 4,5-dimercapto-l,3-dithiol-2-thione Ni(dmit)2 have been the most commonly utilized electron acceptors (see Table 8). Metallic behavior in charge transfer complexes is believed to originate in the facile electron movements in the partially filled bands and in the interaction of the electrons with the vibrations of the atomic lattice (phonons). Lowering the temperature causes fewer lattice vibrations and increases the intermolecular orbital overlap and, hence, the conductivity. The good correlation obtained between the position of the maximum of the charge transfer absorption band (proportional to... 

Construction of LB films having lateral d.c. conductivities is a burgeoning activity. Results of published work are summarized in Table 9 [726-772]. The first formation of a conducting LB film was reported by French workers in 1985 [726]. Non-conducting LB films were formed from N-docosylpyridinium TCNQ. Subsequent exposure to iodine vapor resulted, however, in the lateral conductivities in the order of 0.1 S cm-1 [726]. The initially formed LB film was shown to consist of (TCNQ. )2 dimers whose molecular planes were almost parallel to the substrate. Iodination resulted in the development of a brown-purple color, the partial oxidization erf the radical anions to TCNQ° and, most importantly, a dramatic rearrangement of the LB film. In iodine-doped films, the TCNQ molecules have been shown to assume a position almost perpendicular to the substrate [721, 773],... 

Langmuir-Blodgett (LB) films prepared from N-docosylpyridinium and TCNQ, transferred to substrates, and exposed to iodine vapor Visible and infrared spectra and low-angle X-ray diffraction Lateral d.c, conductivity was about lO- Scm 1 726, 729... 

Monolayers of octadecylpyridinium+-(TCNQ-l,45)" formed and compressed on a glyceryl subphase, shifted to a water subphase, and transferred to solid substrates to form LB films Visible and infrared spectra Lateral d.c. conductivity was 10"4 Scm"1 730... 

LB films prepared from N-docosylpyridinium (TCNQ)2 and transferred to substrates Absorption and infrared spectra Lateral d.c. conductivity was determined to be 10"2 Scm"1, even without iodine doping 739, 740... 

Monolayers prepared from TMTTF octadecyl TCNQ and TTF-octadecyl TCNQ on glycerin subphase Surface-pressure/surface-area measurements and in situ conductivity Lateral d.c. conductivity was of the order of 1 Scm"1 741... 

Lateral d.c. conductivity of iodine-doped 762 film was about 1 x 10 4 S cm 1... 

LB films prepared from hexadecyl-TCNQ TMTTF and (heptadecyl-dimethyltetrathia-fulvalene)2 TCNQ and from their mixtures Electron microscopy and electron diffraction Molecular packing determined conductivities best lateral d.c. conductivity was 0.5 S cm -1 765... 

LB films prepared from metal complex salts (R+)2[Ni(dmit)2]2, (R +)2-[Ni(mnt)2]2 and R+[Ni(dmit)2]- (where R = (CH3)2 (C12H25)2N+), transferred to substrates, and exposed to bromine vapor Surface-potential and conductivity measurements Lateral d.c. conductivities of bromide exposed films were in the 0.001 to 0.28 S cm 1 range 767... 

LB films prepared from poly(thiophene-3-acetic acid)-stearylamine and from sulfonatedpolyaniline-stearylaminepolyion complexes, transferred to substrates, and doped by acid FTIR, X-ray diffraction, and conductivity measurements Lateral d.c. conductivities of acid-doped films as high as 0.05 S cm"1 were obtained 768, 769... 

Pyrrole polymerized at the interface of non-polymerizable 3-octadecanoyl pyrrole and transferred to substrates to form LB films FTIR and conductivity measurements Lateral d.c. conductivities as high as 0.1 S cm 1 were obtained 769, 770, 771... 

Superconductors have infinite d.c. conductivity (ie. zero resistivity) but display normal resistance above a certain frequency. Superconductors are perfectly diamagnetic and totally exclude the magnetic flux. 

Sharp discontinuity in temperature-dependent lateral d.c. conductivity was observed... 

Lateral d.c. conductivity increased with increasing temperature at room temperature, lateral d.c. conductivity = 25 S Cm-1... 

Polyimide film pyrolyzed (to graphitelike polymer) at 100 °C in vacuum had lateral d.c. conductivity up to 600 Scm-1... 

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