Two‐dimensional NMR studies of molecular dynamics in heterogeneous polymers

Abstract

AbstractAdvanced two‐dimensional solid‐state NMR techniques making use of 1H spin diffusion and high resolution 13C detection are powerful tools for the non‐destructive investigation of polymer morphologies and domain sizes. The spin diffusion coefficients needed for quantitative analysis have been calibrated for both rigid and mobile polymers by combining NMR, X‐ray scattering and electron microscopic measurements on diblock copolymers of known morphologies. It turns out that NMR is particularly sensitive to detect small domains in the range of 2–10 nm, and to residual heterogeneities in larger domains, reflected in changes of chain mobility. Last, but not least, NMR is a sensitive tool for characterizing interfacial regions.The techniques will be introduced and demonstrated on various block copolymers including core shell systems, polymer blends and layered systems of rigid rods and flexible side chains. There, the side chain mobility is directly related to the chain conformation and density modulations within the layers.