They call it a shear thickening fluid, but this is just a good old fashioned colloid suspension, just like corn starch 'Oobleck'. With some success, they use the Ph of the carrier fluid glycol to make silica have active silanol groups to space the particles. My approach uses RTILs - ionic liquids- to do the same thing, but via steric (polymer) stabilization. The benefits of my approach are:
- negligible offgassing. This means an infinite shelf life. RTILs are nonvolatile.
- potentially very low toxicity and water permeability, and
- possibly overall lower viscousity than glycol.
The combination of qualities required are:
- short side chains (toxicity), and
- replace alkyls with silyl groups in the side chains (viscousity).
See http://www.organic-chemistry.org/topics/ionic-liquids.shtm for a primer.
See bmim fp6 for a water stable and water immiscible RTIL.
http://lem.ch.unito.it/didattica/infochimica/Liquidi%20Ionici/Toxicology.html
Note side chain length and chemical content role in toxicity.
Maybe you have read about the scandalous Zylon armor fabric. It has failed some % of US troop vests, and I read about over a 50% failure rate for some police forces. Turns out the new wonder fabric deteriorates due to water. Well, assuming the wetting properties permit (and we can always mix an RTIL with something that will evaporate later to do this), the water impermeable RTIL *could* protect Zylon, while providing unprecedented soft armor protection.
Using the following instructions (see http://www.iupac.org/publications/pac/2001/pdf/7308x1309.pdf), I should be able to 'roll my own' custom RTIL for about $500 for used equipment, plus chemicals.
I'm posting this for posterity, to show I was the FIRST to propose this.
Cheers.
http://www.bsstgmbh.de/BSSTV20/html/english/eS031002.htm
This is a link to just how bad Zylon's water degradation is.
Good news! Adding a polymer to a steric-stabilizing liquid not only lowers the viscosity, but also functions as a wetting agent! This leaves me a with a focus on toxicity and Ph. Offgassing of the polymer is next to be investigated.