Molecular Dynamics of Poly(Ethylene Glycol) Intercalated in Clay, Studied Using 13C Solid-State NMR

Abstract

In this study, Cross-Polarization Magic-angle Spinning CP/MAS, 2D Exchange, Centerband-Only Detection of Exchange (CODEX), and Separated-Local-Field (SLF) NMR experiments were used to study the molecular dynamics of poly(ethylene glycol) (PEG) inside Hectorite/PEG intercalation compounds in both single- and double-layer configurations. The results revealed that the overall amplitude of the motions of the PEG chain in the single-layer configuration is considerably smaller than that observed for the double-layer intercalation compound. This result indicates that the effect of having the polymer chain interacting with both clay platelets is to produce a substantial decrease in the motional amplitudes of those chains. The presence of these dynamically restricted segments might be explained by the presence of anchoring points between the clay platelets and the PEG oxygen atoms, which was induced by the Na+ cations. By comparing the PEG motional amplitudes of the double-layered nanocomposites composed of polymers with different molecular weights, a decrease in the motional amplitude for the smaller PEG chain was observed, which might also be understood using the presence of anchoring points.

Influence of the polymer structure of polycarboxylate-based superplasticizers on the intercalation behaviour in montmorillonite clays

“…Thus, it is hypothesized that the intercalation of PCE side chains has the capacity to promote exfoliation of montmorillonite clay and, as it is observed, this capacity increases in PCE polymers composed by large side chains and having high side chain density. An analogue behaviour is described in [34][35][36][37][38] by studying the effects of the length of linear PEO (poly-ethylene oxide) polymers for the synthesis of organo-clay nanocomposites from exfoliated clays, concluding that the longer the polymer chain, the higher the intercalation and the greater the exfoliation.…”

Flexible Nanofiber‐Reinforced Solid Polymer Lithium‐Ion Battery

“…This can indicate a stronger association of Li + in the polymer–ceramic matrix than in the polymer matrix alone. In other words, Al 2 O 3 fibers additionally bind to Li + and can directly affect the segmental motion of PEO chains, which then affects the Li + movement due to the change in the coordination sphere around Li + …”

Modification of ibuprofen drug release from poly(ethylene glycol) layered silicate nanocomposites prepared by hot‐melt extrusion

“…The differences in expansion of the galleries of the two nanoclays used may be attributed to the different conformations and arrangements of the surfactants on the layered silicates, and thus the initial size of the intergallery spacing, in addition to the larger aspect ratio of the fluoromica (S) ∼600, compared to montmorillonite (M) ∼280. 23 A further consideration is the anchoring of PEG oxygen atoms with clay platelets induced by Na + cations …”