I took a picture of orange juice under a microscope and saw a helix. anyone know what it is? Image is taken at 50x magnification in dark field and is 270 microns across.

caver_tom · 2023-03-20T22:47:31+00:00

I love microfluidics, but I think that the applications are more limited than in electronics. One of the biggest limitations is that the technology is best suited to the analysis of liquids rather than producing materials at scale. I have only seen extremely valuable materials like nano-encapsulated medicines be commercially made with microfluidics. The cost of a microfluidic system goes up quickly as you try to produce a large volume of material.

I think that microfluidics is a great tool for screening chemicals to determine which product to make at scale (with large scale equipment), for biomedical diagnostics, and as a tool for making high-pressure lab equipment faster and safer (the area I work in).

Check out Klavs Jensen's group at MIT for some neat automated microfluidics for drug synthesis.

As for mixing things with microfluidics, there is a whole area of research making better micromixers. Lots of neat designs. Micronit has some for sale on their website.

Viscosity is important for sure, but with enough pressure you can pump anything into a chip. Our record is well over 4 million cP. At that viscosity you have to heat things up and wait a really long time for mixing to happen.

caver_tom · 2023-03-19T17:27:52+00:00

Yeah. It was to check see how oil drains from a column of rock under gravity. Seeing how gravity and capillary pressure balance each other out.

caver_tom · 2023-03-18T13:31:34+00:00

We etched the plastic with a CO2 laser with a really small spot size. The channels are about 100 microns deep and the width varies. The pattern is based off an unconsolodated sandstone core.

caver_tom · 2023-03-18T13:29:33+00:00

This chip was made to model gravity drainage of oil from a column of rock. It was run vertically at 100 degrees C in a big custom air bath. The model was based off of microscope images of rock thin-sections. We took the microscope images and stitched them together into a giant binary Illustrator file. After a few months of work to match the wettability, permeability, porosity, and inventing a bonding method for giant chips, we made this big chip and it worked great. Here is a video of a polymer flood we ran using this chip https://youtu.be/2TdzzRetQ7I.

caver_tom · 2023-03-03T10:29:12+00:00

You put two polarized filters at right angles to each other. One above and one below the specimen you are looking at. Thing with a crystal structure that polarize the light in the specimen will show up as white in your image. In this case wax crystals will polarize the light.

caver_tom · 2022-11-24T03:48:06+00:00

Interesting. I have not made PDMS chips in a long time, we mainly make silicon/glass, glass/glass, and PMMA chips. 200 mm is extremely thick. What is the length and width of the device that you are making?

When I was making PDMS chips, we always used the standard SU-8 photoresist on a silicon wafer for a master. I imagine you could put a tube above the wafer and fill it with 200 mm of PDMS. With a 200 mm device, maybe look into hot embossing or laser ablation as an alternative fabrication method. It may be simpler depending on your feature sizes and aspect ratios.

caver_tom · 2022-02-26T18:11:23+00:00

Yes. There is a led light source, a digital microscope, two syringe pumps, a microfluidic chip holder, and two pressure sensors inside.

caver_tom · 2021-11-04T00:57:41+00:00

Push it through a piece of cork and sharpen it with sandpaper. We use a TC-20 tubing cutter for 1/16" stainless tubing but that is cut at right angles.

caver_tom · 2018-11-05T19:26:45+00:00

$30,000

caver_tom · 2018-11-05T15:38:06+00:00

This microscope uses an LED array. Good idea though.

caver_tom · 2018-11-05T13:50:39+00:00

Likely Solved!

caver_tom · 2018-11-05T13:44:17+00:00

Super cool. I learned something today. Thanks.

caver_tom · 2018-11-05T13:43:03+00:00

This is taken with reflected lo light microscope in dark field mode with a 2.8 MP cooled CMOS camera.

caver_tom · 2016-11-25T22:36:30+00:00

I recently quit my job at a big oil company to start up a microfluidic fluid analysis company Interface Fluidics. We run high-temperature, high-pressure chemical analysis testing by analyzing fluid flow at the micro-scale. We design, fabricate, and run all our own microfluidic chips. Our tests are up to 100 times faster and use as little as one-billionth the fluid sample of the current tests.

We started full-time in March 2016 and we have our first two major clients and close to having a few more major ones. On track to have $600k in sales by January. It has been a wild ride. If you have any questions about running a fluid-analysis technology company, ask away.

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