Early stages of oligomer-polymer diffusion

We present results of neutron reflectivity measurements of plasticiser diff usion into high molecular weight deuterated poly (methyl methacrylate) (dPM MA). These measurements were made in situ and in real time, enabling the in terfacial profile to be studied in detail in situations where the normal 'a nneal-quench' procedure is impossible. From the velocity of the diffusion f ront, the diffusion coefficients for two molecular weights, of oligo-methyl methacrylate (OMMA) have been determined. Oligo-poly(ethylene glycol) (PEG ) diffusing into dPMMA has also been measured and limited solubility of PEG observed. (C) 2001 Elsevier Science Ltd. All rights reserved.