Spin diffusion in block copolymers as studied by pulsed NMR

Abstract

Spin diffusion in a heterogeneous polymer system, the styrene-diene–type block copolymer, has been studied using pulsed NMR. It is shown that there is a possibility the spatial dimension can be determined quantitatively from the Goldman-Shen experiment by the active use of spin diffuison. The regular structure and the small distribution of the domain sizes of block copolymers make a quantitative study possible. The possibility that the microscopic profile of the domain interface can be determined from the spin-diffusion experiment is also shown. The spatial information obtained from NMR reflects the spatial distribution of the mobility of the molecules. The spatial resolution of this technique seems to be very high because of the short-range nature of the dipole-dipole interaction. This method is nondestructive and applicable to systems for which other methods, such as transmission electron microscopy, are unsuitable.