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Langmuir‐Schaefer Films of Processable Poly( o ‐ethoxyaniline) Conducting Polymer: Fabrication, Characterization and Application as Sensor for Heavy Metallic Ions
Author(s) -
Ram Manoj Kumar,
Bertoncello Paolo,
Nicolini C.
Publication year - 2001
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200105)13:7<574::aid-elan574>3.0.co;2-i
Subject(s) - quartz crystal microbalance , monolayer , materials science , metal ions in aqueous solution , analytical chemistry (journal) , cyclic voltammetry , electrochemistry , thin film , langmuir , metal , ion , doping , conductivity , differential pulse voltammetry , nanotechnology , electrode , chemistry , adsorption , organic chemistry , optoelectronics , metallurgy
Langmuir isotherms of poly( o ‐ethoxyaniline) (PEOA) were investigated at two different subphases containing deionized water at pH 3 using HCl. The doping during the monolayer formation was observed to be an essential condition for obtaining the high quality of the Langmuir film. The PEOA Langmuir‐Schaefer (LS) films were manufactured, and linearity in the deposition process was verified by using UV‐visible, quartz crystal microbalance, current–voltage, atomic force microscopy (AFM) and cyclic voltammetric (CV) techniques, respectively. The regularity of PEOA LS films could be well maintained by either dedoping the films in NaOH or redoping in 1 M HCl. The linear variation in frequency change as well as systematic doping in PEOA LS films was studied by quartz crystal microbalance measurements. AFM study depicted that the LS films were composed of regular grains of 23±5 nm in diameter. The PEOA LS films showed a conductivity value of 0.001 S/cm. The electrochemical surveyings of PEOA LS films revealed a switching halftime of 300 ms. The presence of heavy metallic ions in the solution revealed well‐separated oxidation peak potentials in cyclic voltammetric measurements. This work presents the first evidence in recognition of heavy metallic ions in a solution using PEOA LS films by differential pulse voltammetric (DPV) technique. The DPV study on PEOA LS films in metallic‐ions‐containing solution showed the distinctive oxidation potentials at 370 (Fe 3+ ), 170 (Hg 2+ ), −130 (Cu 2+ ), −512 (Pb 2+ ) and −720 (Cd 2+ ) mV, respectively. The Pb 2+ ions concentration between 0.1 and 5 ppm was detected using PEOA LS films.