Controlling the chain dynamics of polymers at interfaces

Solid state proton NMR with fast magic angle spinning has been used to study a low T-g acrylate polymer in bulk and polymerized in a vycor glass with 40 Angstrom ports. The combination of chain motion and fast magic angle sample spinning averages the proton-proton dipolar interactions such that high resolution spectra can be observed at ambient temperature. Multiple-quantum NMR shows that some of the chains are severely restricted relative to the bulk material by incorporation into the porous glass. These restricted chains can be returned to their bulk-like state by surface treatment of the porous glass. (C) 1999 Elsevier Science B.V. All rights reserved.