Diffusion process of methane molecules in cylindrical channel cavities of oriented polyester with long n-alkyl side chains as studied by field-gradient 1H NMR spectroscopy

Pulse field-gradient spin-echo 1H NMR experiments on methane molecules charged into cylindrical channel cavities in the hexagonal columnar phase of oriented poly(p-biphenylene terephthalate) with long n-dodecyl side chains have been carried out in order to elucidate diffusion process of the methane molecules in the directions parallel and perpendicular to the cylindrical channel cavity axis. From these experimental results, it is found that methane molecules in the cylindrical channel cavities are not only diffusing in the direction parallel to the cylindrical channel cavity axis, but are diffusing through the wall of the cylindrical channel cavity.