Rheo-NMR. How nuclear magnetic resonance is providing new insight regarding complex fluid rheology

摘要

Nuclear Magnetic Resonance was independently discovered in 1945 by Edward Purcell, Felix Bloch and their co-workers at Harvard and Stanford universities. Soon after that discovery, it was realised that NMR was exquisitely sensitive to the nuclear environment in condensed matter. This sensitivity arises through terms in the spin Hamiltonian related to the detailed chemistry of the molecular host (the chemical shift and the scalar spin-spin coupling), to the orientational order of the host molecules (the nuclear quadrupole interaction with the local electric field gradient), to the spatial and orientational distribution of these molecules (the inter-nuclear dipolar coupling), and to the molecular dynamics (nuclear spin relaxation processes). In 1973, the discovery that NMR performed in the presence of magnetic field gradients enabled imaging of the nuclear magnetization density, led to the development of MRI as an important tool in modern radiology.