Poly-o-anisidine

Polypyrrole was the first conducting polymer used as ion-to-electron transducer in solid-state ISEs [43], and is still one of the most frequently used [45-68]. Other conducting polymers that have been applied as ion-to-electron transducers in solid-state ISEs include poly(l-hexyl-3,4-dimethylpyrrole) [69,70], poly(3-octylthiophene) [44,70-74], poly(3,4-ethylenedioxythiophene) [75-86], poly(3-methylthiophene) [87], polyaniline [44,67,73,88-99], polyindole [100,101], poly(a-naphthylamine) [102], poly(o-anisidine) [67] and poly(o-aminophenol) [103], The monomer structures are shown in Fig. 4.1. 

Gupta and Warhadpande [177] chemically prepared substituted polyaniline by polymerizing m-toluidine, o-toluidine, o-anisidine, acetanilide, diphenylamine and o-naphthylamine. The thermogravimetric studies revealed that the ring-substituted polymers were less stable than the N-substituted polymers as evident from the weight loss at 800°C for poly(m-toluidine) (62.2%), poly(o-toluidine) (61.6%), poly(o-anisidine) (100%), poly(acetanilide) (51.9%), poly(diphenylamine) (29.5%) and poly(o-naphthylamine) (69.72%), which also indicates that the stability of strained-chain polymers is less than that of flat-chain polymers. 

Paddeu S., Ram M. K., Carrara S., and Nicolini C., Langmuir-Schaefer films of poly (o-anisidine) conducting polymer for sensors and displays. Nanotechnology, 9, 228-236, 1998. 

Bavastrello V., Ram M. K., and Nicolini C. Synthesis of multiwalled carbon nanotubes and poly(o-anisidine) nanocomposite material Fabrication and characterization of its Langmuir-Schaefer films, Langmuir, 18, 1535-1541, 2002. 

Polyaniline and its substituted derivatives, such as poly(o-toluidine), poly(o-anisidine), poly(N-methylaniline), poly(N-ethylaniline), poly(2,3-dimethylaniline), poly(2,5-dimethylaniline) and poly (diphenylamine) have been reported [36] to show measurable responses (sensitivity 60%) for short chain alcohols (viz., methanol, ethanol and propanol) at concentrations up to 3000 ppm. The change (decrease) in resistance of the polymers on exposure to alcohol vapors has been explained based on the vapor-induced change in the crystallinity of the polymer. Polypyrrole (PPy) incorporated with dodecyl benzene sulfonic acid and ammonium persulfate has been reported to show a linear change in resistance when exposed to methanol vapor in the range 87-5000 ppm [37]. The response is rapid and reversible at room temperature. 

PNMA, poly(N-methylaniline) PANI, poly(aniline) PEDOT, poly(3,4-ethylenedioxythiphene PSS, poly(styrene-sulfonate), PPy, poly(pyrrole) PEO, poly(ethylene oxide) DBSA, dodecylbenzene sulfonic acid CSA, camphor sulfonic acid PTSA, poly(o-toluene sulfonic acid) PFOA, perfluoro-octanolc acid TSA, toluene sulfonic acid CNF, carbon nanofiber SWCNT, single-walled carbon nanotube NP, nanoparticle MWCNT, multiwalled carbon nanotube PTh, poly(thlphene) CNT, carbon nanotube POA, poly(o-anisidine) SPANI, poly(anilinesulfonlcacld) PB, Prussian Blue DAB, 1,2-diamino benzene POEA, poly(o-ethoxyanlllne) PMMA, poly(methyl methacrylate). 

L. Valentini, V. Bavastrello, E. Stura, I. Armentano, C. Nicolini, and J.M. Kenny, Sensors for inorganic vapor detection based on carbon nanotubes and poly(o-anisidine) nanocomposite material, Chem. Phys. Lett, 383, 617-622 (2004). 

C. Sivakumar, Finely dispersed Pt nanoparticles in conducting poly(o-anisidine) nanofibrillar matrix as electrocatd3hic material, Electrochim. Acta, 52, 4182 190 (2007). 

Notes PNEA=Poly(N-ethylaniline), POEA=Poly(o-ethyl aniline), PM-ABA=Poly(anUine-co-m-amino benzoic acid), POA=Poly(o-anisidine), PoPD= Poly(o-phenylenediamine), and PMA= Poly(o-methoxyaniline). 

Poly(o-anisidine)/CNTs (POA-CNTs) Chemical deposition Deposition on a substrate HCl [22]... 

Poly(o-anisidine)/tin oxide (POA-SnO ) In-situ chemical polymerization Pellet Humidity [50]... 

Introducing derivatives and copolymers of PANI also results in different ER effect because of different molecular structure and electrical properties, e.g., poly(o-anisidine), poly(anihne-co-o-ethoxy aniline), poly(o-tolu-idine) (POT), substituted PANI (with long alkyl pendants, PDOA), poly(N-methyl aniline) (PNMAn), poly(N-ethyl aniline) (PNEAn), and poly(2-ethyl anihne) (P2EAn) with reduced conductivity [36,37]. 

Composite fibers of poly(o-anisidine]-PS was produced by electrospinning for chemical vapor sensing. Sensibility of the composite fibers were tested under water and ethanol vapor, the sensors elements responded better to the high polarity ofthe solvent. The CSA-doped POA/PS composition seems to be stable under the submitted ambient conditions to ethanol. The sensor could be reused several times without any change in sensing behavior and/ or damage to the sensing materials. 

Recently, ultrathin films of poly(o-anisidine) and poly(ethoxyaniline) have been fabricated for application in nanotechnology [64-66]. Matsura and co-workers [67] have fabricated monolayers of 3-carotene using a Langmuir-Blodgett film technique together with the flow-orientation method. They have utilised XRD, UV-visible and FTIR techniques to elucidate the film-structure of P-carotene indicating that P-carotene orients perpendicular to the air-water interface. It was found that the films are, however, well-ordered both in the stacking direction and the in-plane direction. 

Schottky devices have recently been fabricated by thermal evaporation of indium on polyaniline, poly(o-anisidine) and poly(aniline-co-or oanisidine), respectively [103]. The values of the rectification ratio, the ideality factor and the barrier height of an indium/poly(o-anisidine) have been experimentally determined as 300,4.41 and 0.4972, respectively. The observed deviation from the Schottky behaviour for these devices seen at higher voltages has been explained in terms of either the Poole-Frenkel effect or due to the presence of a large number of defects containing the trapped charges existing at the indium/poly (aniline-co-or oanisidine) interface. 

Patil, S., S.R. Sainkar, and P.P. Patil. 2004. Poly(o-anisidine) coatings on copper Synthesis, characterization, and evaluation of corrosion protection performance. Appl Surf Sci 225 (1-4) 204. 

Ozyilmaz, A.T., Ozyilmaz, G., and Yigitoglu, O. (2010) Synthesis and characterization of poly(aniline) and poly (o-anisidine) films in sulphamic acid solution and their anticorrosion properties. Prog. Org. Coat., 67, 28-37. 

PABS poly-(m-aminobenzene sulfonic acid), PEG poly(ethylene glycol), PEI polyethyleneimine, PDPA polydiphe-nylamine, PMMA poly (methyl methacrylate), POAS poly(o-anisidine), PPy polypyrrole... 

Leclerc et al. [35] have compared POT and PMT with poly(2-ethylaniline) and poly(3-ethylaniline). Poly-(ethylanilines) show a similar electrochromic behavior to polytoluidines. They also exhibit similar optical properties as found for polytoluidines. Poly(ethylani-lines) exhibit multiple and reversible color changes (pale yellow-green-blue violet) depending on the oxidation state and the pH. Poly(2-ethyIaniline) shows a higher conductivity (1 S cm" ) compared to that of polytoluidines (0.3 Scm" ). Ryoo et al. [75] have compared the photoconductivity of POT with those of PANI, poly(o-ethylaniline) and poly(o-anisidine). The photoconductivity spectra of the polymers resemble their electronic absorption spectra. Therefore the band structures of POT and other PANI derivatives are similar to that of PANI. A major contribution to photoconductivity of these polymers comes from the n— n transition while the polaron—tt transition contributes to a lesser extent. Ryoo et al. [75] have proposed that photoexcitation leads to the oxidation of the polymer due to the removal of electrons. The bandgap energies of POT are the lowest (3.03 and 2.48 eV) while those of PANI are the highest (3.45 and 2.82 eV). 

Pandey et al. [983] described In/CP Schottky devices fabricated via thermal evaporation of In on chemically synthesized P(ANi), poly(o-anisidine) and poly(aniline-co-o-anisidine). In the case of die last copolymer, the rectification ratio, ideality factor and barrier height were found to be 300, 4.41 and 0.497 V respectively, while they were 60, 5.5 and 0.510 V for the P(ANi) device. Bantikassegn and Inganas described [984] a Schottky contact made from poly(3-(4-octylphenyl)-2,2 -bithiophene) (P(TOPT)) in its neutral and PF -doped states and Al metal as the sandwich structure ITO/P(TOPT)/Al. Rectification ratios for the neutral and doped CP were observed to be ca. 5 and 3 orders of magnitude respectively, with diode quality factors (n) being 1.2 and 4.2 respectively. Liu et al. [122] fabricated Schottky diodes from L-B films of poly(3-alkyl-thiophenes) doped with an... 

Aussawasathien D, Sahasithiwat S, Menbangpung L, Teerawattananon C (2011) Poly(o-anisidine)-polystyrene composite fibers via electrospinning process surface morphology and chemical vapor sensing. Sens Actuator B Chem 151(2) 341-350. doi 10.1016/j.snb.2010.07.048... 

By mixing polyaniline with a small amount of acetic acid, it is possible to form stable films at the air-water interface which can be readily transferred into high quality Y-type LB films. Conductivity values of 0.1 to 1 S/cm were obtained [294]. Poly(o-anisidine) was... 

---