Interpolymer complexes of poly(methacrylic acid) and poly(2-alkyl-2-oxazolines): pH-mediated assembly, quantum-chemical insights into hydrogen-bond structure, and iodine vapour sorption

Makhayeva, D. N., Tolegenova, D. A., Abiyeva, A. M., Irmukhametova, G. S., Mun, G. A., Smyslov, R. Y., Gorshkova, Y. E., Ivanova, V. E., Tomilin, F. N. and Khutoryanskiy, V. V. ORCID: https://orcid.org/0000-0002-7221-2630 (2026) Interpolymer complexes of poly(methacrylic acid) and poly(2-alkyl-2-oxazolines): pH-mediated assembly, quantum-chemical insights into hydrogen-bond structure, and iodine vapour sorption. Polymer, 356. 130028. ISSN 0032-3861 doi: 10.1016/j.polymer.2026.130028

Abstract/Summary

The pH-mediated assembly of hydrogen-bonded interpolymer complexes between poly(methacrylic acid) and poly(2-alkyl-2-oxazolines) was investigated in aqueous solutions. Critical pHs (pHcrit) of complexation were determined across a range of polymer concentrations. The pHcrit shifted to higher values with the formation of interpolymer complexes moving from poly(2-methyl-2-oxazoline) to poly(2-ethyl-2-oxazoline) and poly(2-n-propyl-2-oxazoline), reflecting changes in hydrophilic-hydrophobic balance. Geometry optimisation and electronic structure calculations of the hydrogen bonding in the interpolymer complexes were performed using the quantum-chemical DFTB method with 3ob-3-1 parameters and the Grimme D3(BJ) dispersion correction. These calculations revealed that the most energetically favourable hydrogen bond structure involves the carbonyl oxygen of poly(2-alkyl-2-oxazoline) forming a bond with the hydrogen of the protonated carboxylic group of poly(methacrylic acid). Infrared spectroscopy and thermal analyses of these interpolymer complexes in the solid state were performed and show the presence of interactions between the polymers. The sorption of iodine vapours by the interpolymer complexes, as well as by the individual polymers, was investigated. It was found that poly(methacrylic acid) exhibits poor iodine sorption, whereas poly(2-alkyl-2-oxazolines) demonstrate a strong affinity for iodine. Complexation with poly(methacrylic acid) significantly reduces the ability of poly(2-alkyl-2-oxazolines) to sorb iodine vapours.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/129395
Identification Number/DOI	10.1016/j.polymer.2026.130028
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > School of Pharmacy > Pharmaceutics Research Group
Publisher	Elsevier
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