Posted by jerry wigutow on Nov 14th, 2023
With aerogel being hyped primarily to the military I decided to research into what exactly it is.
What is Aerogel?
1.The most common type of aerogel, silica aerogel [definition; a highly adsorbent gelatinous form of silica, used chiefly as a dehumidifying and dehydrating agent.], is derived from a solgel reaction in which the liquid filled pores have been replaced with gas. This results in an extremely low-density solid that can be imparted with several remarkable properties such as hydrophobicity.[definition; having little or no affinity for water.]
2.Why is Aerogel a Good Thermal Insulator
The solid component in silica aerogel consists of tiny, three-dimensional, intertwined clusters. They comprise only 3% of the volume and are very poor conductors. Air in microscopic pores make up the remaining 97% of aerogel’s volume. This air has very little room to move, inhibiting both convection and gas-phase conduction. These characteristics make aerogel the world’s lowest density solid and most effective thermal insulator.
The following explanation explains why aerogel is not the most effective insulator or will ever be.
I looked at a picture of these “tiny three dimensional intertwined clusters” and I can only guess that these clusters are spread over a particular space which is not reported. The air in the “microscopic pores” that has very little room to move will certainly not allow for convection or gas-phase conductive heat lose.
Theoretically this is true if confine from what I have seen to very small areas about 6 inches square and 1 to 2 inches thick. You can actually look through this material because it has no density.
The problem the aerogel people as well as all other companies delving into the field of insulation have is their lack of understanding density of the insulating medium is crucial to the retention of heat coming into the insulating medium where the density of the insulating medium attaches to the air molecules. In the case of Lamilite continuous filament fiber it is a solid fiber, no microscopic pores to harbor air. But the air molecules that have attached to the fibers [remember air attaches to any and all surfaces for a distance of 1/8 inch and less so convective or conductive heat lose is insignificant. The warm air attaches to the thousands of surfaces of the continuous filament fibers so it goes no place or better said it is stuck.
The aerogels “tiny, three-dimensional intertwined clusters” have to be incorporated with a carrier of some sort, enter primaloft.
"PrimaLoft® Cross Core™ - Intro
For the first products within our PrimaLoft® Cross Core™ platform, we infused PrimaLoft materials with aerogel that was orginially developed by NASA for aerospace applications. Aerogel is the lightest solid material on earth - comprised of more than 95% air. To produce the insulation, particles of aerogel are embedded into the PrimaLoft fiber itself, delivering enhanced lightweight warmth".
Here we go again; developed by NASA, big deal. As you can see primaloft is the carrier. I can only guess as to how these two products are integrated which is to say they are put in a blender and mixed up and then put through a web forming machine and then the web goes into an oven where the low melt fiber liquifies to hold the non-low melt fibers together and the “tiny, three dimensional clusters" get swallowed up by the liquified low melt fiber. They are now embedded in the primaloft.
How can they now work, they can’t because their host isn’t much of an insulating material? When the temperature goes below 40 degrees F primaloft stops working so the delivery of “enhanced lightweight warmth” does not happen, unless of course you are thinking 40 degree warmth.
Doing more research into the aerogel insulation I found what they call “solarcore”. Since the use of pure aerogel leaves a lot to be desired. It will shatter like glass or will dissolve in water. Further research found that the solarcore product has the “tiny three dimensional intertwined clusters”, remember them apparently applied to “sc foam” which I think is probably a urethane foam. The picture shown on their website shows it sort of undulating to me. this is what they use in their jackets. It is soft and pliable so the garments feel good to the touch.
I also noted they have a US patent number on their web site #107937771, however when I looked it up all that comes up is a Chinese patent that has nothing to do with aerogel. The search actually told me there is none. Maybe I am looking in the wrong place.
In any event, we now know there are two carriers of the “tiny three dimensional intertwined structures” a polyester fiberfill product sold by primaloft and the sc foam product sold by oros in use in their garments. They may also offer it to other outerwear makers.
The more I have learned about aerogel the more I am convinced there are other materials available that are insulators that are significantly les expensive as well as being easier to work with that are more efficient, number one being continuous filament fiberfill.
So, the U.S.A.F. Research Laboratory at Wright -Patterson AFB can keep I believe wasting our tax dollars since they are hyped up with aerogel.