Nuclear magnetic resonance relaxation study of the organization of layers of poly(ethylene oxide) chains grafted on silica

The proton nuclear magnetic resonance (n.m.r.) relaxation times of poly(ethylene oxide) grafted on silica were determined at 300 MHz. The dependence of the temperature and grafting ratio on the relaxation times is discussed qualitatively from a phenomenological point of view. Two models are proposed for the surface layer for the two extreme grafting ratio levels. At a low grafting ratio the chains lie very hat, whereas at a high grafting ratio, the layer is more organized. Data obtained for the proton relaxation time as a function of temperature show the existence of a transition for each grafting ratio used. Copyright (C) 1996 Elsevier Science Ltd.