Contact angle of ALD treated membranes
This is a quick post on comparing the contact angle after ALD on pnc-Si with aluminum oxide vs the untreated material (+/- ozone). The hypothesis is that the angle should drop since Al2O3 is hygroscopic.
The angles are 85°, 45°, 61°, and 50° for the untreated, ozone, Al2O3, and Al2O3 and ozone case, respectively. These results are promising w.r.t. membrane wetting.
Update:
I repeated the experiment above, except I treated the membranes this time with the YES O2 plasma.
Looks like the O2 plasma is more effective at making a hydrophillic surface. The contact angles from left to right are: 83°, 14°, 56°, and 18°.
I looked back at my notes and found that +ozone should give a contact angle of 20 degrees.
I’ll give the YES O2 plasma treatment a try…
Do we know if the Al2O3 coated membranes processed in the YES system show wet-dry flow? I’m cautiously optimistic, since these 2 processes leave a highly hydrophilic surface that uniformly coats both the membrane surface and the interior of the pores. It’s unlikely that oxidation alone on bare membranes accomplishes this.