Rouse 2D diusion of polymer chains in low density precursor films of polybutadiene melts

We took advantage of pseudo-partial wetting to promote the spreading of precursor films whose surface density smoothly decays to zero away from a sessile droplet. By following the spreading dynamics of semi-dilute precursor films of polybutadiene melts on silicon wafers, we measure molecular diusion coefficients for different molar masses and temperatures. For homopolymers, chains follow a thermally activated 2D Rouse diffusion mechanism, with an activation energy revealing polymer segments interactions with the surface. This Rouse model is generalized to chains with specific terminal groups.