Pedot Filtering Problem

Hi! All
I was wondering if anyone has advice on filtering/storage of
Pedot-PSS. We purchased the high conductivity solution (about 10-100
ohm/square) from Aldrich and stored it in a fridge.
We now notice (after a few months of storage) that pedot is
precipitating on the sidewalls. Also, filtering it using nylon/pvdf
filter/cellouse nitrate paper (tried 0.2micron and 5 micron) seems to
be problematic...
I would appreciate any ideas on optimal storage (room temp?) and
filtering procedures for this material. Further, in there data on the
change viscosity and other parameters with filter size?
Regards
Rama
Reply to
Ramakrishna Maruvada
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The water in the dispersion might be drying out at the edges. Try storing at room temperature in a humidified atmosphere. This might be as simple as suspending a water moistened rag over the headspace in a closed container (be sure to use deionized water as tap water will have calcium and magnesium ions that will cause problems with the sodium chemistry of the PEDOT solution), and then if you can slightly pressurize the closed container, that will slow down the drying process by increasing the vapor pressure over the solution.-Jitney
Reply to
jitney
Hmm... don't know much about history, geography or Pedot solutions.
But I do find your last statement a little problematic.
Loss of water from the solution will stop when partial pressure of H2O over the solution is equal to the vapor pressure of the solution, irrespective of the total pressure. Thus if we pressurize moist air it might help, but if we increase the pressure but adding dry air or N2, it might make things worse.
About the moist rag idea: is the solution hygroscopic? The problem may be reversed from evaporation to dilution!
Reply to
Edward Green
I'm just trying to be practical. What inspired the last suggestion is the well known practice of using a humidor for cigars, wherein a strip of fabric or sponge is kept moist to keep the cigars from drying out. As long as it is moist and not dripping wet, I see no danger of dilution.-Jitney
Reply to
jitney

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