I’ve looked at 100 nm Membranes from both sides now…
While JK has been processing backside images from 50 nm, 75 nm, and 100 nm membrane SEM images for pore information, I thought I’d take a look at a 100 nm membrane from both the front and the back at the same spot. Here are the images referenced to a corner of the trench. The corner is easier to see on the backside (left) image but is still discernible from the front by the lightened area at the top and right of the image.
I scaled them to equal size, flipped the backside image over, extracted the pore image and superimposed this onto the topside image. I indicate the edge of the bulk silicon with a blue line. There is some skewing going on as you can see the pores do not align well even in the limited area in the top image of the following figure. These are scaled correctly so you can see the pore size differentials. I then skewed the image to get the majority of the holes to align and show more of the image. You can still get a sense of how much reduction can occur and how some holes are not completely transferred all the way to the backside. I don’t really have a point with this, I just liked the idea of making the direct comparison from both sides. Bonus points to anyone who gets the musical reference in the post’s title.
Nicely done. And you didn’t give me a chance on the trivia.
The sieving curves for 100 nm material appears to be not at all sharp, while the 50 nm and 75 nm are. I’ll post when the data is completely in, but I’m not yet seeing anything in the structure that explains this.
Actually the preliminary sieving curves are in Karl’s latest post.
Trivia answer below…. Sorry to spoiled it for early readers. 🙂
“I’ve looked at clouds from both sides now
From up and down and still somehow
It’s cloud’s illusions I recall
I really don’t know clouds at all”
Joni Mitchell
I’m not done looking at all the data yet, but JK is reporting that the 50 nm membranes have an average pore size in the single digits. 9 nm to be precise. I’ll review his data and we’ll make a blog post with all the histograms and average pore size for 50, 75, and 100. Soon. Before you get back from your conference.