Conformation of poly(ethylene oxide) intercalated in clay and MoS2 studied by two-dimensional double-quantum NMR

The conformation of poly(ethylene oxide), PEG, intercalated in layered clays and MoS2 has been characterized by double-quantum solid-state NMR. Using PEO with 13% C-13-C-13 labeled units, the conformational statistics of the OC-CO bonds have been determined. The OC-CO bonds of the polymer in narrow interlayer gaps of similar to 0.8, similar to 0.85, and similar to 1.0 nm thickness consistently exhibit a high gauche content of approximately 90%. This rules out models with highly trans-containing chains as found in certain complexes of PEO with HgCl2 or p-nitrophenol.