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Download fileDoping of Polyaniline with 6‑Cyano-2-naphthol
journal contribution
posted on 2014-11-13, 00:00 authored by Debasree Das, Anindya Datta, Aliasgar Q. ContractorThe conductivity of polyaniline (PANI)
is ascribed to its emeraldine
salt (PANI-ES), which is formed by protonation of its emeraldine base
(PANI-EB) by acids. Generally, mineral acids are used for this purpose,
but the use of dopants and additives to maintain the required acidity
provides an alternative method to the preparation of PANI-ES. The
present work attempts to achieve the protonation by the use of a weak
organic acid, namely, 6-cyano-2-naphthol (6CN2), which is generally
used as a superphotoacid, as its excited state pKa is significantly smaller than its ground state pKa. The question here is if the protonation of
the aniline moieties in PANI takes place and if it does, whether it
takes place by dissociation of the ground state or the excited state
of 6CN2. Room temperature conductance measurements were carried out
to see the effect of doping. The formation of PANI-ES from PANI-EB
has been monitored by UV–vis spectrophotometry. When a polar
counterion is inserted into the polymer matrix, it changes the environment
of the nearby chains by introducing defects, reorganization of charges
as a result of interaction with the polymer. Morphological investigation
was done using optical microscopy, field emission gun scanning electron
microscopy (FEGSEM), and field emission gun transmission electron
microscopy FEGTEM. The influence of 6CN2 on the crystallinity of the
polymer was determined by X-ray diffraction (XRD).
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state pKamineral acidsfield emission gun transmission electron microscopy FEGTEManiline moietiesground state pKaFEGSEM6 CN 2work attemptsXRDUVfield emission gun scanning electron microscopyemeraldine baseprotonationemeraldine saltalternative methodMorphological investigation6 CN 2. Room temperature conductance measurementsground statepolymer matrixPANI