Electrostatic interactions in chains of copolymers N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride

Dommes O.A.1, Gosteva A.A.1, Okatova O.V.1, Pavlov G.M.1,2

1Institute of Macromolecular Compounds of the Russian Academy of Sciences, St. Petersburg, Russia
2Saint Petersburg State University, Department of Physics, St. Petersburg, Russia
oljaspb552@gmail.com

The change of size of charged macromolecules is one of the fundamental problems of polymer physics [1]. The size of the chains of strong polyelectrolytes depends both on the average charge density of the chain and on the ionic strength of the solution. The fractions of the hydrophilic random copolymer N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride (MVAA-MVAH) with different linear charge density (96:4 mol.%, 92:8 mol. %, 84:16 mol.%) have been studied at different ionic strength. Previously, homological series of uncharged homopolymers PMVAA [2] and MVAA-MVAH copolymers 56:44 mol.% [3] were investigated.

The molecular masses of MVAA-MVAH copolymer fractions were calculated from the sedimentation-diffusion analysis data carried out under suppression of polyelectrolyte effects in 0.2 M NaCl solutions. Information on the dimensions and conformation of MVAA-MVAH linear chains at low  ionic strength (~ 10-6M) is obtained from the study of the viscous flow of their dilute solutions. The influence of the contributions of the electrostatic short- or long-range interactions to the dimensions of polyelectrolyte chains is discussed.
References:
[1] Dautzenberg H., Jaeger W., Koetz J., Philipp B., Seidel C., Stscherbina D. Polyelectrolytes: Formation, Characterization, and Application. Munich, Hanser-Gardner Publications, 1994.
[2] Pavlov G.M., Okatova O.V., Mikhailova A.V., Ulyanova N.N., Gavrilova I.I., Panarin E.F. Macromol. Biosci. 10, 790 (2010). 
[3] Pavlov G.M., Okatova O.V., Gubarev A.S., Gavrilova I.I., Panarin E.F. Macromolecules 47 (8), 2748 (2014).
Acknowledgements
The polymers were synthesized in the Laboratory of hydrophilic polymers of the IMC RAS. Authors are very thankful to the head of laboratory, Corresponding Member of RAS, Professor E.F. Panarin and to the scientific researcher of the laboratory I.I. Gavrilova.