Ultra thin polymeric membranes

Polymer membranes are an emerging "green-technology" in various fields of application: pure gas production, CO2 capture, sensors, food packaging, to name but a few. Their operating principle is based on the selective mechanism of solution/diffusion of gases within the polymers. One of the limitations of this technology is due to the still insufficient rate of gas permeation through them. For this reason, technological efforts are directed towards the manufacture of ultra-thin membranes with nanometric thicknesses. Experiments carried out at DIFI have revealed that, below a particular thickness, permeation does not increase as the thickness decreases in the manner predicted by the models used to date. This effect is due to phenomena of unbalanced surfaces that cannot be overlooked when the thicknesses become less than a few tens of micrometers. Also in DIFI laboratories, the influence of surface roughness on the mechanisms of gas transport through these membranes has been verified. In particular, rough surfaces increase the gas flow rate of membranes whose thickness is such that the equilibrium conditions cannot be considered to be met.

The activities carried out at the DIFI concern the following aspects:

  • The manufacture of polymeric, thick and ultra-thin membranes.
  • The measurement of the permeability of these membranes with an experimental set up consisting of a high vacuum apparatus equipped with state of the art instrumentation in terms of resolution and accuracy, and free of artifacts to the extent typical of other commercial apparatus.
  • The nanostructuring of polymeric surfaces to study their influence on the gas transport properties of ultra-thin membranes