PDADMAC/PSS oligoelectrolyte multilayers: Internal structure and hydration properties at early growth stages from atomistic simulations

Pedro A. Sánchez*, Martin Vögele, Jens Smiatek, Baofu Qiao, Marcello Sega, Christian Holm

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We analyze the internal structure and hydration properties of poly(diallyl dimethyl ammonium chloride)/poly(styrene sulfonate sodium salt) oligoelectrolyte multilayers at early stages of their layer-by-layer growth process. Our study is based on large-scale molecular dynamics simulations with atomistic resolution that we presented recently [Sánchez et al., Soft Matter 2019, 15, 9437], in which we produced the first four deposition cycles of a multilayer obtained by alternate exposure of a flat silica substrate to aqueous electrolyte solutions of such polymers at 0.1M of NaCl. In contrast to any previous work, here we perform a local structural analysis that allows us to determine the dependence of the multilayer properties on the distance to the substrate. We prove that the large accumulation of water and ions next to the substrate observed in previous overall measurements actually decreases the degree of intrinsic charge compensation, but this remains as the main mechanism within the interface region. We show that the range of influence of the substrate reaches approximately 3 nm, whereas the structure of the outer region is rather independent from the position. This detailed characterization is essential for the development of accurate mesoscale models able to reach length and time scales of technological interest.

Original languageEnglish (US)
Article number25081848
JournalMolecules
Volume25
Issue number8
DOIs
StatePublished - Apr 1 2020
Externally publishedYes

Keywords

  • Atomistic simulations
  • Charge compensation
  • Hydration properties
  • Layer-by-layer deposition
  • Molecular dynamics
  • Polyelectrolyte multilayers

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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