PANI-CSA

FIGURE 1.4 Optical transmission spectra of (a) PEDOT-PSS and (b) PANI-CSA. 

FIGURE 1.5 (a) Temperature dependence of electric conductivity (b) infrared electric conductivity of PANI-CSA. 

For PLEDs with relatively small active area, the anode can be made of a single layer of conducting polymers with relatively high bulk electric conductivity. Gustafsson and coworkers at UNIAX demonstrated a flexible PLED with conducting PANI-CSA anode, and... 

Fig. 6.36 Response of PANI/CSA/IL WF CHEMFET to ammonia (adapted from Saheb, 2008)...

Fig. 3.12. Transmission electron micrograph for PANI-CSA (0.1%)/PMMA blend near the percolation threshold...

Fig. 3.13. Resistivity vs. T for PANI-CSA/PMMA blends at various volume fractions / of PANI...

In unoriented metallic conducting polymers like PANI-CSA, PPy-PFf, PEDOT-PF6, etc. [[Pg.111]

Rannou P, Nechtschein M (1998) PANI-CSA films Ageing and kinetics of conductivity degradation. J Chim Phys Physico-Chimie Biol 95 1410-1413... 

Fig. 30 Strongly enhanced electronic conductivity of PANI(CSA)o.5(Hres)j after self-assembled cylinders are formed above a critical amount / of 4-hexylresorcinol [231]...

Fig, VI-7 shows the electrical conductivity vs, weight fraction of the PANI-CSA complex in polyblends with PMMA [61,282,283], The results are typical in that a similar smooth onset for conductivity is observed with a number of host polymers fabricated with appropriate compatible counterions (e,g, DBSA for polythylene, etc,) [282,283], As shown in Fig, VI-7, these PANI blends are remarkable in that electrical conductivities of order 1 S/cm can be obtained in a polyblend containing only about 2% of the conductive component, with no indication of a sharp percolation threshold [284],... 

The smooth onset of electrical conductivity at such low volume fractions of PANI-CSA in the conducting polyblends indicates an unusual morphology, with connected pathways even at remarkably low volume fractions of the conducting... 

PANI-complex. Thus, the transport data suggest the formation of a self-assembled interpenetrating fibrillar network of PANI-CSA during the course of liquid-liquid phase-separation. 

TEM micrographs of blends made from 0.5% and 0.25% PANI-CSA in PMMA are shown in Fig. VI-8 (a and b) [61,279]. The PANI-CSA network can be seen quite clearly. Fig. VI-8 (a and b) resemble the typical scenario imagined for a percolating medium [277] with links (PANI-CSA fibrils), nodes (crossing points of the links) and blobs (dense, multiply connected regions). In the sample containing 0.5% PANI-CSA numerous weak links are clearly visible while for the 0.25% sample there are rather few links between the nodes and blobs. This indicates that at volume fractions below 0.5% PANI-CSA in PMMA, the network is unstable and tends to break up into disconnected blobs [285]. 

A more detailed relationship between conductivity and volume fraction of PANI-CSA in PMMA is shown at low volume fractions in the inset to Fig. VI-9. In order to identify the percolation threshold more precisely, the data were fitted to the scaling law of percolation theory [277],... 

At room temperature and at 10 K, the values of the electrical conductivity of PANI-CSA/PMMA samples with f—f, are of the order of 10 S/cm and 10 S/cm, respectively values which are remarkably high [285] For comparison, polyaniline blends made by dispersing intractable polyaniline in host polymers [286] show percolation only at much higher levels, 4 8.4%. In such samples, the room temperature conductivity at f. is five orders of magnitude lower, of the order of 10 S/cm [286]. 

Figure VI-8 TEM micrographs showing the network morphology of PANI-CSA in blends with PMMA (a) f=0.5%, and (b) f=0.25%. The organization of the conducting polymer as a network of interconnected pathways varies with the concentration of PANI-...

Films cast from various solutions have been investigated by the same authors [331], They find essentially two different x-ray diffraction patterns. In the case of PANI-CSA, these correspond to films cast from M-cresol and DMSO, respectively, and they are also found for distinct processing procedures of PANI-DBSA. Each of these diffraction patterns corresponds to a characteristic UV-vis absorption spectrum of the solid, which is also very similar to the spectrum of the solution used to prepare the material. The emergence of the different crystal phases is therefore attributed to different chain conformations in the solution from which the films were cast. A helical main chain conformation is proposed for the crystal phase obtained... 

In other PANl systems protonated with HBF [266], HCl [261,278] and H2SO4 [303], temperature-independent susceptibility is observed. In PANI-CSA the electrical conductivity tr behaves as a metal, that is, a oc /T, above 200 K [304] and in PANl-HCI the microscopic conductivity obtained from the spin dynamics showed the semiconductor-to-metal transition around 150K [305,306]. Furthermore, the metallic optical absoiption was found in PANI-HBF, [280]. Then the temperature-independent susceptibility could be assigned to the Pauli susceptibility in these systems. 

Other authors point out that in PANI-CSA/PMMA composites [148], the distance between PANI fibrils (observed by TEM) are assumed to be of the order of (400-800 A) for 0.5% concentration. 

The earlier theimopower data for PAni/PVC blends [80] are similar to that for the blends in Figure 11.56, except for negative values at very low temperatures. In the only other data on PAni blends, the theimopower of PAni-CSA/PMMA blends measured by Yoon el al [102] is very close to that of the PAni/PMMA blends investigated here, in magnitude as well as temperature dependence (except for small negative values seen at very low temperatures). These data further emphasise the similarity of PAni blend thermopowers. The theimopower of the pure PAni does appear to be significantly smaller than that of the blends small thermopowers (of either sign) have been seen for some PAni samples by other authors [93,94,95]. 

CSA was dissolved through ultrasonication in deionized water, networks of PANI-NFs with spherical nodes, nanoparticles, leaf-vein-shaped nanofibers, etc. were obtained, depending on the strength of the ultrasonic treatment. PANI-CSA nanofibers having diameters 1-2 nm were produced by bath sonication of aqueous dispersions of larger nanofibers (30-50 nm diameter) [41]. 

Au/PANI-CSA coaxial nanocables have been successfully synthesized by the oxidation of aniline with chloroauric acid in the presence of CSA [397]. PANI-CSA nanotubes were obtained by dissolving the Au nanowire core of the Au/PANI-CSA nanocables. Purified flagella fibers displaying an anionic aspartate-glutamate loop peptide with 18 carboxylate groups were used to initiate formation of PANI-NTs [398]. 

PANI-CS A nanofibers, synthesized by an interfacial polymerization method, are readily dispersed in water, which could facilitate environmentally friendly processing and biological applications [133]. The nanofibers are stable in water, in contrast to conventional PANI/CSA thin films, which can be dedoped by water. PANI-NFs synthesized by dilute polymerization were also easily dispersed in various solvents, polar as well as nonpolar, and the resulting suspensions were stable for several minutes [171]. 

Composites of PANI-NFs, synthesized using a rapid mixing method, with amines have recently been presented as novel materials for phosgene detection [472]. Chemiresistor sensors with nanofibrous PANI films as a sensitive layer, prepared by chemical oxidative polymerization of aniline on Si substrates, which were surface-modified by amino-silane self-assembled monolayers, showed sensitivity to very low concentration (0.5 ppm) of ammonia gas [297]. Ultrafast sensor responses to ammonia gas of the dispersed PANI-CSA nanorods [303] and patterned PANI nanobowl monolayers containing Au nanoparticles [473] have recently been demonstrated. The gas response of the PANI-NTs to a series of chemical vapors such as ammonia, hydrazine, and triethylamine was studied [319,323]. The results indicated that the PANI-NTs show superior performance as chemical sensors. Electrospun isolated PANI-CSA nanofiber sensors of various aliphatic alcohol vapors have been proven to be comparable to or faster than those prepared from PANI-NF mats [474]. An electrochemical method for the detection of ultratrace amount of 2,4,6-trinitrotoluene with synthetic copolypeptide-doped PANI-NFs has recently been reported [475]. PANI-NFs, prepared through the in situ oxidative polymerization method, were used for the detection of aromatic organic compounds [476]. 

It is also interesting to note that polyaniline doped with camphor sulfonic acid (PANl-CSA) was intercalated into M0O3. This was achieved by adding PANI-CSA dissolved in m-cresol to an aqueous sol of LixMo03- The stoichiometry of the intercalate as determined from elemental analysis was (PANI-CSAo.i24)i 06M0O3. Evidence of intercalation was obtained from powder X-ray diffraction [59]. 

PANI/CSA, PTSA, PFOA nanorods, nanoparticles Cond. 53 = 0.91-0.97 52-120 s Langmuir-Blodgett films [31]... 

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