Transport in Thin Polymer Films

Blandine Jerome, Investigator

We study the transport properties of confined polymeric systems, with a special focus on a) the anisotropy of the diffusion through confined systems, and b) the effect of the conformation of polymer chains on transport. This also involves the development of Resonance Soft X-ray Reflectivity to obtain the necessary orientational information on polymer chain conformation.

We study in parallel the structure of confined polymers (developing and exploiting new possibilities offered by Resonant Soft X-ray reflectivity) and the resulting transport properties revealed through dynamic mass uptake measurements with a quartz microbalance.  Nanostructured films of mixtures of homopolymers blended with block copolymers are used to tune the sample geometry in which transport is measured. We compare the properties of coil-shaped, rod-like and helix-shaped molecules.

Figure: permeation of molecules through a polymer film, illustrating the two steps involved: 1) absorption (governed by solubility) and 2) diffusion. Both steps are influenced by the confinement of the polymer into thin films and need to be studied independently.