Dr. George's Blog: Equipment and parts to build the AeroGel manufacturing device

While studying energy conservation Mr.B's the class got very interested in a material called Aerogel. Aerogel is the lightest solid know and it makes a very good insulator. The problem is that it requires supercritical CO2 at a pressure 74 time that of atmospheric pressure to make it. Besides the safety concerns the price of a machine that can reach those pressures with a substantial volume is cost prohibitive.

Luckily the students found SeaGel a version of Aerogel that is made from Agar Agar (boiled sea weed jello). I tried to make so but my first attempt looked more like jello beef jerky. The trick is to freeze the Agar Agar and pump all the water away before it melts. That is called Freeze drying. When my first attempt melted before it dried I just made dried jello not freeze dried jello.

My second attempt worked much better but the chamber was small and there was only room to make pea sized bits.

Our next attempt was to try to building a freeze dryer (lyophilized) with two chambers. One chamber for the sample and a second chamber to trap the water that leaves the sample. The idea was to be able to independently control the temperature of the two chambers. The sample would be in an ice/salt water bath to hold it at -20 degrees C. While the water trap would be in a bath of rubbing alcohol and dry ice at -80 C. If all went well the water would sublimate from the first chamber and be trapped in the second. Here is a video showing the parts.

Fun with a vacuum pump. I wanted the students to have good understanding of the vacuum pump that we were going to use in making our Aerogel. So we did some experiments.