NEUTRON REFLECTIVITY STUDY OF A POLYMER SOLID INTERFACE

The density distribution in a polymer melt in the vicinity of a solid surface was probed using neutron reflectivity measurements. Preliminary measurements were conducted on polychlorotrifluoroethylene in contact with a silicon single crystal. A significant difference in reflectivity was observed between the free silicon surface and the polymer-silicon interface. This difference can be attributed to the polymer density fluctuation near the interface. Dramatic changes in the reflectivity were observed as the sample temperature decreased below its melting point. A qualitative interpretation of the results based on surface enhanced crystallization of the polymer is presented. This work demonstrates that neutron reflectivity is a promising technique for probing polymer structure near a solid surface.