Structure of tethered polymer chains immersed in a solution of mobile polymer

Neutron reflectivity has been used to characterize the structure of a tethered polymer layer in contact with a solution of mobile polymer chains. The tethered polymer layer is a stable Langmuir film of block copolymer spread on the surface of a selective solvent. The insoluble block remains on the surface of the solvent and acts as an anchor for the soluble block which dangles in the solution. In the absence of mobile polymers in the solvent, moderate stretching of the tethered chains is observed over a large range of surface density and for different molecular weights. The effects of mobile chains on the structure of the tethered layer have been investigated. The different regions of interpenetration of the mobile and tethered chains have been explored by varying the concentration and chain length of the mobile polymer.