Attempt at UV/Ozone to Clean Membranes of Organic Impurity
I tried to clean samples from W615 using UV/ozone to cleanse the membranes of the organic impurities we have been seeing lately. I followed the UV/ozone protocol, with a stage temp of 25C and treatment time of 5 minutes. No change in the impurities were observed; I plan on trying to run it again for a longer time (15 minutes).
I ran UV/ozone for 15 minutes, and no change on 2 of 3 samples was observed. On the third the spots were still present, but the membrane had wrinkles, originating at the spots.
So these are not organics? Still, they are not pinholes, right?
Under the TEM, I’ve seen the smaller dark spots burn up. It looks like the ozone took care of these smaller spots, too. I’m not sure what the composition of the larger spots are, though. Next time I’m at the TEM I can try using EDX to identify it…
These are most likely organic. I would try using the max temperature (150C?) and try 15, 30, and 60 minutes to see what happens. The ozone cleaning is probably quite gentle, especially at room temp.
Also, are these mounted vertically or tilted in some way to allow gas to circulate to both sides of the membrane? Wrinkling could result if both side are not treated in the same way.
Looking at these using EDAX is probably a good idea to make sure there are no surprises.
I will try and run the UV/ozone at a higher temperature for a longer amount of time. I also tilted the samples, having one edge on a glass slide and another on the metal surface.
I tried to clean the contamination off of W615 with a stage temperature of 100C and run times of 15, 30, and 60minutes (n=2 for each). As previously observed the small dark spots were removed but the larger spots remained present in all three tests durations.
Also, out of the for each of the time intervals the membranes were tilted within the UV Ozone chamber and only one of the six total samples wrinkled (on of the 15minute ones).