Electron microscope animation: Carbon nanotubes pulled into thread

today on Applied Science I'm going to show you how I used the scanning electron microscope to make an animation of carbon nanotubes being pulled into a thread in my last video I showed how to make carbon nanotubes and one of the unusual properties of these is if you make the carpet of carbon nanotubes in just the right way you can actually pull a thread out of it almost like you're unraveling a sweater or a piece of fabric but an important difference is that instead of unweaving something that was intentionally woven this is basically a bunch of random carbon nanotubes that just stick together in just the right way so that they all get pulled into a thread just sort of naturally it's really kind of a bizarre process and so I wanted to zoom in with the electron microscope and really see what was going on right at the junction where this thread is being produced out of the carpet of carbon nanotubes this animation required close to 600 frames which I painstakingly acquired by hand and had the added complication of changing the zoom level of the microscope at the same time that I was pulling the thread out pretty much micron by micron and so if we stop here at the highest resolution you can almost make out individual carbon nanotubes or at least bundles of them as it turns out this process is actually bundles of bundles getting pulled out of the sheet of carbon nanotubes and then I run the animation in Reverse just for kicks here so it looks like the carbon nanotubes are getting pushed back in this animation most electron microscopes have just one stage on them so you basically put your object inside the microscope and then you use these knobs on the outside to move the stage around so that you can you know get the microscope aimed at what you want but this particular microscope is unusual and then it has two stages so the big knobs on the bottom here control this lower stage and the knobs up here control the upper stage and I have this pressurized at the moment so we can look inside and the idea is that I put the carbon nanotubes on the upper stage and then have this support connected to the lower stage to which I've attached the thread so basically by moving the stages relative to each other I can pull the thread out and I have really good control because these things are micrometers so I can pull the thread out a micron at a time and collect a frame the electrical wires here are a pass through so that I can turn the power on and off to things that are inside the microscope so in a previous video I showed an integrated circuit that I was powering and looking at with a microscope at the same time so for now I'm going to close this up and then start the pump down cycle so that will vacuum out the inside of the chamber and I'll show you the process that I went through to collect this animation this is quite a vintage electron microscope and was built long before computers for doing digital image acquisition so normally use the scope just by looking at the green screen CRT here and if we move the micrometers around you can see the image changes because it's moving the sample inside there and you can see it on here live video but the problem with this is that the resolution of the image is not very good when the machine is running at live video speeds so to get a better image what we do is slow down the scan by pressing this button and now the machine is scanning through the image very slowly and doing a better job basically collecting a higher resolution image and I have it hooked up to the computer here so that the computer is just collecting all of these screen information that's coming out of the microscope but this only works at this slow scan setting so basically each frame takes about 10 seconds to acquire and what I do to collect this animation is basically just move the knob a tiny amount wait 10 seconds for the frame to be saved to the computer and move them into the knob again and for a long animation like this if close to 600 frames it's too tedious to start and stop the acquisition each time so I basically set up the computer to just grab every single frame and then what I do is wait until the frame is almost to the end and then quickly move the knob a teeny amount before the next frame starts so the computer just continuously acquires the scanning electron microscope just continually sends the frames out and I just make the adjustment in between very quickly check the description for links to some of my previous projects where I went into detail about how this image acquisition system works and you can see some of the other animations that I've made with this microscope since I wanted this animation to have a change in magnification or zoom level I had an additional problem here this scope only has discrete steps of magnification so if we zoom in you can see the magnification going up but it's only delivered in these discrete steps and so what I wanted was to have a nice smooth zoom in through this Meg through this animation so what I did was collect about 50 or 60 frames at each zoom level and then save each of those as a separate set of frames and then in my video editing software I took each set of frames and made a video out of that and then zoomed in to the video and set it up such that the zoom would very very perfectly match the next zoom level up and all of this was linearly interpolated so it's not quite as you know silky smooth as it might be but it's kind of where we currently are with the state of doing this animation one of my long-term projects is to build a much more sophisticated acquisition device so currently sitting here for an hour and a half and twiddling the knobs is okay but what would be even better is to have stepper motors on each of these micrometers over here and then I could basically program the computer to run the entire animation so stepper motor advances this by 10 microns collects a frame you know advances this 10 microns again collects another frame and obviously that would be my life a lot easier so I wouldn't have to sit here and also the quality of the animation would be much higher since it's just everything would be more controlled something I'd really like to do is have full motion control so instead of just one or two dimensions moving at the same time it would be really nice to have you know zooming panning and tilting all at the same time and you have to refocus the thing potentially every at every frame so if the computer could do all of that including some sort of a simple autofocus routine then we would really have something and I feel like this you know electron microscope animation technique is really underutilized in industry this scope is very old and manual that modern scopes already have all this equipment built in so ant-man you frame capture that could be triggered by an animation sequencer motors on all of the axes and autofocus control are all already there so basically we've just be a software exercise to give a sense of era you can see this microscope has a film counter here and so originally the way that you would do image acquisition is take a Polaroid camera and strap it on to the front here and then set the camera shutter open and do a single scan and then take your film out and that's how you would actually capture an image the device even will put scale bars into the image so you'll actually be able to make measurements but that part of this instrument is actually broken for some reason it doesn't produce the scale bars anymore the more advanced image acquisition system that I have planned for this is quite a project it would probably involve an FPGA and much much higher bandwidth and data acquisition you know very at least three or four channels of stepper motor control auto focusing and I think it's it's maybe I'm shooting a little bit too high so maybe so you know for the next implementation of this maybe just stepper motors with the existing frame capture network or something but anyway it's gonna be a pretty cool project and I hope to make some really nice you know cinematic style electron microscope animations so I hope you found that interesting and I will see you next time bye

Channel: Applied Science

Views: 237,462

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Id: FBIzCp24Ix0

Length: 8min 6sec (486 seconds)

Published: Sat Feb 22 2020

Reddit Comments

[u/DiaDeLosMuertos]

Holy shit seems so tedious. Yet awesome results.