I'm trying to make small 3.5 radii membranes from polyurethane pellets dissolved in THF(10%polymer solution). I'm casting them in aluminum pans and tried both air-drying in a hood and vacuum drying, but when I try to peel the membranes off...they cohere to themselves and won't unstick...kinda...
Since the membrane is hydrophobic, most permeable species probably interact with the membrane through london dispersion forces. Thus, ethanol has a higher molecular weight than methanol and will have more affinity for the hydrophobic membrane.
Floosh.
I'm looking for a material that is permeable to water vapor but impermeable to larger gas molecules (50-150 m.w.) and potentially impermeable to toxic/hazarodous fumes/gases.
I am searching for POTENTIAL membranes (flexible and thin) that are water vapor permeable and may be barriers to low molecular weight toxic/hazardous fumes/gases. Anyone know where to look?