Influence of Backbone Solvation on Small Angle Neutron Scattering from Polyelectrolyte Solutions

Abstract

Recent theoretical and experimental studies of polyelectrolyte solutions have suggested that hydrophobic interactions between the chain backbone and the solvent lead to some of the essential observations of polyelectrolyte solution scattering. In the current paper we present small angle neutron scattering data on a polyelectrolyte, poly(N-methyl-2-vinylpyridinium chloride) dissolved in ethylene glycol where the hydrophobic effect is not present. This system shows the same general pattern, a peak at finite wavevector and steep upturn at low wavevector, as for those having hydrophobic interactions so that the influences of poor backbone solvation appear to be unessential for explaining the characteristics of polyelectrolyte scattering data. We demonstrate that in the scattering from polyelectrolytes after the addition of salt, the unusual peak and steep upturn are suppressed and the scattering parallels scattering from the neutral chains.

Scattering Study of the Structure of Polystyrene Sulfonate Comb Polyelectrolytes in Solution

“…SANS is sensitive to changes in scattering length density and SLS to changes in the refractive index. [35] Both scattering length density and refractive index map the presence of the polymer chains in solution and the two techniques may be assumed to probe the same structure i.e. the chain conformation and shape.…”

Scattering properties of salt-free wormlike micellar solutions

“…The numerous experiments performed by static and dynamic light scattering revealed features which are still not understood. One can quote in particular the upturn of the scattered intensity in the low scattering vector range and the presence of slow modes in the time autocorrelation function of the scattered field [6][7][8][9][10][11][12][13][14]. Furthermore, most experiments have been performed in solutions of highly charged polyelectrolytes for which the phenomenon of Manning condensation introduces a supplementary difficulty.…”

Ternary Complex Formation in Aqueous Solution between a β‐Cyclodextrin Polymer, a Cationic Surfactant and DNA

“…However, a few authors have tentatively ascribed this upturn to the existence of localized ordered clusters in solution [39] and incipient macroscopic phase separation. [37] When poly(b-CD), DTAC and DNA are mixed together in D 2 O, a significant increase in the scattering intensity values is observed in the low q-range (in comparison to the poly(b-CD)/DTAC/D 2 O and poly(b-CD)/DNA/D 2 O systems). This result indicates the formation of large interchain aggregates in the medium.…”

“…The observation of such a peak is a recurrent finding of SANS studies from polyelectrolyte solutions. [36][37][38] From a theoretical viewpoint, the peak in the scattering pattern from polyelectrolyte solutions is interpreted as an ordered structure in the medium. This peak disappears progressively when salt is added and, consequently, it is interpreted as resulting from long-range electrostatic interactions that impose a preferential distance between the charged particles in solution.…”