Fluctuation suppression in microgels by polymer electrolytes

S Pasini; S Maccarrone; N K Székely; L R Stingaciu; A P H Gelissen; W Richtering; M Monkenbusch; O Holderer

doi:10.1063/4.0000014

Fluctuation suppression in microgels by polymer electrolytes

Struct Dyn. 2020 Jun 15;7(3):034302. doi: 10.1063/4.0000014. eCollection 2020 May.

Authors

S Pasini¹, S Maccarrone¹, N K Székely¹, L R Stingaciu², A P H Gelissen³, W Richtering⁴, M Monkenbusch⁵, O Holderer¹

Affiliations

¹ Forschungszentrum Jülich GmbH, JCNS at Heinz Maier-Leibnitz Zentrum, Lichtenbergstraße 1, 85747 Garching, Germany.
² NScD, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
³ Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany.
⁴ Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen and JARA-SOFT 52056 Aachen, Germany.
⁵ Jülich Centre for Neutron Science (JCNS) & Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.

Abstract

Structural details of thermoresponsive, cationically poly(N-iso-propylacrylamide-co-methacrylamido propyl trimethyl ammonium chloride) microgels and the influence of the anionic electrolyte polystyrene sulfonate (PSS) on the internal structure and dynamics of the cationic microgels have been studied with a combination of small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy. While SANS can yield information on the overall size of the particles and on the typical correlation length inside the particles, studying the segmental polymer dynamics with NSE gives access to more internal details, which only appear due to their effect on the polymer motion. The segmental dynamics of the microgels studied in this paper is to a large extent suppressed by the PSS additive. Possible scenarios of the influence of the polyanions on the microgel structure and dynamics are discussed.