Polyaniline film formation in hexadecyl trimethyl ammonium bromide admicelles on hydrous zirconia surface

There are several types of aniline oligomers that can be formed in the early stages of aniline oxidation: linear oligomers with repeating units joined in para positions, and various branched and polycyclic oligomers, being the two most important groups. The fraction of these different oligomeric groups depends upon the reaction conditions of aniline oxidation. The aim of this study was to analyze the first products of the chemical and electrochemical oxidation of aniline at the (starting) pH 1 and 7, in order to specify the conditions of the formation of phenazine-like oligomers, and to test the theory that they have an important role in polyaniline film formation. We have confirmed that phenazine-like oligomers do not form at pH 1, neither in the chemical nor the electrochemical oxidation of aniline; however, they form in both chemical and electrochemical oxidation of aniline at pH 7. Phenazine-like oligomers are thus definitely not necessary intermediates for PANI film formation, not even in the chemical polymerization of aniline. Finally, the redox behavior of phenazine-like oligomers was demonstrated in a medium at pH 1.

Download Full-text

Ion-Selective Electrode for Anionic Surfactants Using Hexadecyl Trimethyl Ammonium Bromide-Sodium Dodecylsulfate as an Active Ionophore

International Journal of Electrochemistry ◽

10.4061/2011/958647 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Junwei Wang ◽

Zhiping Du ◽

Wanxu Wang ◽

Wei Xue

Keyword(s):

Limit Of Detection ◽

Sodium Dodecylsulfate ◽

Poor Response ◽

Pvc Membrane ◽

Indicator Electrode ◽

Membrane Electrode ◽

Ammonium Bromide ◽

Hexadecyl Trimethyl Ammonium Bromide ◽

Pvc Membrane Electrode ◽

Wide Ph Range

The construction and characteristic performance of PVC membrane electrode responsive to sodium dodecylsulfate (SDS) are described in this paper. The electrode is based on hexadecyl trimethyl ammonium bromide-Sodium dodecylsulfate (CTA+DS−) ion pair as ionophore in PVC membrane, which displays a Nernstian slope of −58 ± 0.9 mV/decade in a 5.0 × 10−6to 2.5 × 10−3 mol L−1concentration range and a limit of detection of 2.9 × 10−6 mol L−1. The electrode can be used for 3 months without showing significant changes in the value of slope or working range. Also the electrode has wide pH range of application and short response time. The electrode shows a selective response to SDS and a poor response to common inorganic anions. The selective sequence found was SDS > HCO3 −> CH3COO−> Cl−> I−> NO3 −≈Br−> F−> CO3 2−> C6H5O7 3−> C2O4 2−> SO4 2−> C4H4O6 2−> SO3 2−> PO4 3−. The potentiometric selectivity coefficients determined are indicating that common anions would not interfere in the SDS determination. The electrode has been utilized as an end point indicator electrode for potentiometric titration involving hyamine as titrant.

Download Full-text