NMR Studies of the Effect of Adsorbed Water on Polyelectrolyte Multilayer Films in the Solid State

Abstract

Fast-MAS 1 H NMR is used to probe the structure and dynamics of the adsorbed water and polymer components in polyelectrolyte multilayer (PEM) films and the bulk polyelectrolyte complex (PEC). The films, ranging in size from a single layer to 5 bilayers, consist of poly(diallyl dimethylammonium chloride), PDADMAC, and poly(sodium-4-styrenesulfonate), PSS, adsorbed onto colloidal silica. Relaxation and line width measurements show that the adsorbed water is less mobile in the films than in the analogous PEC. The environment of the water throughout the film is found to be affected by the nature of the outer layer with the water displaying a higher mobility and chemical shift when PDADMAC forms the outer layer. Relaxation measurements, together with 1 H double-quantum (DQ) NMR experiments, reveal that polymer dynamics in the PEMs are strongly influenced by the layer number and water content. 2D spin diffusion and DQ NMR are used to detect polymer-polymer and water-polymer association. The results support the diffuse interpenetrating model of the different layers and a partitioning of the water to the PSS component and to the surface layer.

Surface thermodynamic properties of polyelectrolyte multilayers

“…The strongly dipolar character (nonzero γ + ) of the swollen films is a clear sign of greater hydration. These results fit very well with data obtained in NMR studies of the effect of adsorbed water on polyelectrolyte multilayers [36]. The NMR data clearly showed that water adsorbed in PDADMAC/PSS multilayers is mainly associated with the more hydrophilic PSS chains and less water is associated with the PDADMAC chains.…”

Force‐Free Patterning of Polyelectrolyte Multilayers under Solvent Assistance

“…Their alternately assembled PSS/PDAD-MAC multilayers have a T g of 35-40 8C when they are fully hydrated in water, which functions as a plasticizer and thereby increases the polymer mobility. [57,58] According to the result of Figure 3a, an apparent transition occurred at about 40 8C, after which the pattern height increased in a faster rate. This is indicative of the T g of the PSS/PDADMAC multilayers, which is consistent with previous values measured by other methods.…”

Probing Proton Mobility in Polyvinazene and its Sulfonated Derivatives Using 1H Solid‐State NMR

“…[8][9][10][11][12][13][14][15][16] Fast magic-angle spinning (30-60 kHz) is vital, as it provides excellent resolution of resonances, particularly in the hydrogen bonding region. Additionally, variable temperature measurements can be used to establish linewidth trends, and correlations to proton dynamics.…”