Trchová M, Bláha M, Dybal J, Stejskal J. Thermally Induced Protonation of Conducting Polyaniline Film by Dibutyl Phosphite Conversion to Phosphate.
J Phys Chem A 2018;
122:9492-9497. [PMID:
30462508 DOI:
10.1021/acs.jpca.8b09582]
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Abstract
The blue thin polyaniline base film changes its color to green after immersion of the film into dibutyl phosphonate. The green color of the film converts to a greenish-blue after heating to 200 °C in air, which is characteristic for the protonated conducting form of polyaniline. This is in contrast to the "standard" polyaniline hydrochloride, which is transformed into a cross-linked polyaniline base under such conditions. To explain this unexpected observation, the interaction of polyaniline base with dibutyl phosphonate at ambient conditions and after heating to 200 °C was studied using UV-visible, FTIR and Raman spectroscopies. On the basis of these studies, we propose that the dibutyl phosphite tautomeric form of dibutyl phosphonate, which interacts with polyaniline base at 20 °C, converts to the oxidized form, dibutyl phosphate, at 200 °C and subsequently protonates the film. Quantum-chemical modeling of the interaction of polyaniline base with dibutyl phosphite and dibutyl phosphate supports this explanation.
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