Liquid Armor: Non-Newtonian Protection from Stabbing & Blunt Force

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Discussion Overview

The discussion revolves around the concept of liquid armor utilizing non-Newtonian fluids, specifically focusing on its potential applications, materials involved, and alternatives to silica nanoparticles. Participants explore the properties of various materials and their effectiveness in providing protection against stabbing and blunt force, as well as the feasibility of DIY experiments.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes liquid armor made from a non-Newtonian fluid (possibly polyethylene glycol) mixed with silica dioxide nanoparticles, highlighting its promising properties for flexibility and lightweight protection.
  • Another participant expresses skepticism about the claims made in a promotional video, emphasizing the need for independent testing before fully accepting the concept.
  • Suggestions for alternative materials include diatomaceous earth and varve clay, with discussions on their respective properties and potential effectiveness compared to silica nanoparticles.
  • One participant notes that clay mixed with water exhibits Newtonian properties, which may not be suitable for the desired non-Newtonian behavior, while sand is mentioned as a better candidate for non-Newtonian fluid behavior.
  • There is a discussion about the hydroclustering effect of silica particles that contribute to hardening upon impact, with uncertainty expressed regarding the effectiveness of larger particle sizes.
  • Participants consider the stability of different fluids, suggesting alternatives like antifreeze to PEG, while acknowledging the limitations of using water due to freezing concerns.

Areas of Agreement / Disagreement

Participants express a range of views on the effectiveness of various materials for liquid armor, with no consensus reached on the best alternative to silica nanoparticles. The discussion remains unresolved regarding the optimal composition and properties needed for effective liquid armor.

Contextual Notes

Some participants mention limitations related to the availability of materials in their locations, as well as the varying properties of different substances that may affect their suitability for use in liquid armor.

sauroman1
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Hello, recently saw video demonstrating newly developed armor based on non Newtonian liquid. Such armor is being still researched but is very promising, flexible, lightweight and can stop even heavy stabs with sharp pricker, maybe even bullets.
Liquid armor itself is based on two components - non Newtonian fluid polyethylene glycol (probably PEG 200 or 600) and bigger part is filling of silica dioxide nanoparticles. Then mix is putted on to layers of material such as kevlar and impregnated into it. Don't know if this liquid won't drip down, but maybe suspension will be enough to stiff if not too thick and can be sealed.
Biggest problem is that these SiO2 nano particles are expensive. So i wanted to know if there are alternative materials that could be used, maybe even harder and different shape. For example I was thinking if ordinary clay could be used instead - it contains hard minerals such as SiO2 and particle size is 0.002mm, they have plate shape.
I need liquid armor for game or just gloves, but if enough effective could be used against stabbing weapons. I'm not worried about bullets too much - in my country there are more chances to die from knives attack not gun. But I guess liquid armor could give variety of protection.

Here video demonstrating this armor:

 
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I love it! Still, I'd approach with caution simply because that video was made by the manufacturer. Independent testing is necessary for me to buy the concept entirely.
If you want to experiment a bit yourself, you can make your own sheer-thickening fluid very easily. Just mix cornstarch and water. It won't have any ceramic properties, but you can get a really good handle on how the material works.
 
That's pretty cool. I'd like to do my own experiments on this sometime. If you can't get a hold of silicon nanoparticles, maybe you can just get some diatomaceous earth, make it finer, and then make some oobleck and throw it in. Diatomaceous Earth has a particle size of around 10-200 micrometers and is 80-90% silicon, so it's better than clay, but a few orders of magnitude worse than the silicon nanoparticles. Still, I'd try it and see what happens.
 
Thanks, but I'll stick to varve clay which I can't get for free. Diatomite contains more silica but unfortunately in my place I can't get it. Moreover clay appears to have even harder minerals such aluminum oxide that is 9 hard in Moths scale, but 20% (maybe aluminum powder could be oxidized and added). Army vest plates are made from 9 level hardness material.
 
Clay doesn't work. Mixed with water it has Newtonian fluid properties, even gets more liquid when pressure applied. But sand acts as non Newtonian fluid. So it's have to do something with silica dioxide properties. PEG is used instead of water because it's more stable liquid.
 
Well you can't just use straight water as the fluid. You'd have to try mixing the clay with something like oobleck (cornstarch + water) to get what you're after.
 
Silica particles are best to use in this case because they have hydroclustering effect which causes hardening on impact but clay doesn't. But I'm not sure if larger size particles would as much effective. For example 0.003mm?
I think any liquid could be used, just PEG is more stable while water may freeze. Probably even antifreeze could be used.
 

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