Abstract Electron spin resonance (e.s.r.) of labelled grafted poly (ethylene oxide) has been used to estimate (as a function of temperature) the ratio between the populations of free-end segments in solution to those adsorbed onto the silica surface. The influence of the solvents such as C 6H 6, CHCl 3, C 4H 8O 2, C 6F 6 and CCl 4 has also been investigated. Better solvents produce greater swelling of the molecules, with more of the grafted layer extending into the solution. But solvent-surface and polymer-surface interactions must be taken into account to explain the results.