The nonlinear change in conformation of polyelectrolyte macromolecules in saltless water‐organic solvent

Abstract

High molecular weight polyelectrolyte: poly(dimethylaminoethy1 methacrylate) CPDMAEMAI with molecular weights &=28.Ox1O6, 20.0~10~. 15.0~10~ was investigated in dilute solution by light scattering, flow birefringence and viscometry (at different rate gradients) in a water-acetone system by varying the weight fraction of acetone r in the mixture.At r=0.76 the polymer undergoes a reversible coil-globule transition accompanied by a drastic decrease in intrinsic viscosity Cnl. mean-square radius of gyration <R%z1'2 and second virial coefficient A2. with no change in molecular weight. The coil asymmetry parameter p (~2 . 5 at r-0.50) decreases with increasing r and attains unity (completely symmetrical particle) at the transition point (r=0.76).The anomalous behavior of the viscosity of PDMAW-water-acetone solutions, detected near the transition point (r=0.6+0.7). is interpreted by formation of local knots of compactization on the molecular chain under the influence of a hydrodynamic field.

Contraction of a Polyelectrolyte upon Dilution. Light Scattering Studies on a Polycation in Basic and Acidic Water−Acetone Mixtures

“…Properties of the water−acetone solutions of the high molar mass polycation poly(methacryloylethyl trimethylammonium methylsulfate), PMETMMS, have been recently discussed. − The polymer has the followingstructure: PMETMMS undergoes a reversible coil-to-globule transition in a mixture of water and acetone, in which acetone acts as a nonsolvent. If the mass fraction of acetone in the solvent, γ, is higher than 0.80, the polymer collapses, and single macromolecules adopt a globular state.…”

Contraction of a Polyelectrolyte upon Dilution. Light-Scattering Studies on a Polycation in Saltless Water−Acetone Mixtures

“…However, the existence of uncompensated charges of polyions prevents the aggregation and makes it possible to follow the coil-to-globule transition using various research methods. [1][2][3][4][5][6] In this paper the concentration dependence of the conformation of the high-molar-mass polycation poly-(methacryloylethyl trimethylammonium methyl sulfate) (PMETMMS) near the point of conformational transition will be discussed. The polymer has the following structure:…”

“…PMETMMS is known to undergo a reversible coil-to-globule transition in a water-acetone mixture, in which acetone acts as a nonsolvent. 1,[3][4][5] If the mass fraction of acetone in the solvent γ is below 0.80, the viscosities of the solutions show the usual polyelectrolyte effect. When γ > 0.80, the polymer adopts a globular state.…”

“…The interactions in aqueous polyelectrolyte solutions are even more complex than those in solutions of neutral polymers. However, the existence of uncompensated charges of polyions prevents the aggregation and makes it possible to follow the coil-to-globule transition using various research methods. − …”

“…In this paper the concentration dependence of the conformation of the high-molar-mass polycation poly(methacryloylethyl trimethylammonium methyl sulfate) (PMETMMS) near the point of conformational transition will be discussed. The polymer has the following structure: PMETMMS is known to undergo a reversible coil-to-globule transition in a water−acetone mixture, in which acetone acts as a nonsolvent. ,− If the mass fraction of acetone in the solvent γ is below 0.80, the viscosities of the solutions show the usual polyelectrolyte effect. When γ > 0.80, the polymer adopts a globular state.…”