Molecular Motion in a Spreading Precursor Film

Hui Xu, David Shirvanyants, Kathryn Beers, Krzysztof Matyjaszewski, Michael Rubinstein, Sergei S. Sheiko
2004 Physical Review Letters  
Spreading of a polymer drop on a solid substrate was monitored with molecular resolution. Three characteristic rates, i.e., the spreading rate of the precursor film D spread 3:9 0:2 10 3 nm 2 =s, the flow-induced diffusion rate of molecules within the film D induced 1:3 0:1 nm 2 =s, and the thermal diffusion coefficient of single molecules D therm 0:10 0:03 nm 2 =s, were independently measured. Since D spread D induced , the plug flow of polymer chains was identified as the main mass-transport
more » ... ain mass-transport mechanism of spreading with an insignificant contribution from the molecular diffusion.
doi:10.1103/physrevlett.93.206103 pmid:15600943 fatcat:7xa2xqewvrazbpiqawpnu2sc5u