Neutron reflectometry is used to measure polymer mobility near an attractive solid surface over distances less than the bulk polymer radius of gyration, Rg. Effective diffusion coefficients, Deff, are determined from the rates of interdiffusion between supported bilayers prepared from three matched molecular weight pairs of deuterated poly(methyl methacrylate) (PMMA) and hydrogenated PMMA. The dPMMA layer is placed next to a silicon surface and its thickness is varied from less than Rg to 11Rg. Deff dramatically decreases in samples with dPMMA layers less than 3Rg thick. The surface induced decrease in polymer mobility is correlated with both direct polymer contact with the substrate and indirect effects from polymer entanglements with the underlying absorbed polymer structure.
, Wu, W.
, Satija, S.
and Kolb, R.
Polymer Mobility Near the Polymer/Solid Interface, Physical Review Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=851396
(Accessed December 8, 2023)