Rigorous science says that malodorous compounds in small concentrations affect the olfactory system, exerting psychological effects and causing behavioral changes. That is, they force a person to frown and leave combat positions in horror in search of a breath of fresh air. Much more serious "smelly" compositions act in medium and high concentrations: they reduce the volume and frequency of respiration, increase skin-electrical reactions, and also cause tachygastria (complex disorders of the stomach, often with vomiting).
The history of such an unusual non-lethal weapon began in the 1940s, when, under the supervision of the US National Defense Research Committee (NDRC), a fetid composition with a persistent fecal odor was developed. In parallel with them, the Office of Strategic Services of the United States, which later became the CIA, was working on sabotage grenades, equipped with the smell of rotting. For a long time, work in such areas was classified, and in 1997 the NDRC released a whole atlas of stinking substances. It turned out that in the United States all this time they were doing painstaking work in this "fetid" direction.
The main bonus of such delicate gases was their protection from international conventions prohibiting the use of chemical weapons. In the United States, they even developed requirements for fetid compositions:
- the smell must be very unpleasant for biological objects;
- the smell must quickly affect the biological object and spread quickly;
- the toxicity of the composition in working concentrations should not exceed levels safe for health.
The greatest difficulties for the authors of such a foul-smelling weapon were with the objectivity of assessing the perception of smell, since this is influenced by the sum of factors: gender, age, characteristics of the nervous system and hormonal levels of a person. In addition, the responses were very wide: from mild discomfort to immediate nausea and vomiting. Over time, chemists have come to the universal structure of a foul-smelling composition, which includes: a solvent (water or oil), an active ingredient (one or more odorants), a fixative and an odor enhancer (for example, skatole). Of course, the main active ingredient responsible for the "aroma" is the odorant (from the Latin odor - smell), which is added to gas or air. Usually these are some sulfur-containing organic compounds with a pungent disgusting odor. For example, these include mercaptans, familiar to everyone by their characteristic smell from a household gas pipe. These compounds (aliphatic thiols) are specially added to natural gas so that the human nose can accurately detect leaks at the lowest concentrations. And what will happen if such thiols are used in concentrated form? Their toxicity is insignificant, but the threshold of perception by the olfactory system is very low, and skunks take advantage of this, producing a complex mixture of thiols in their fetid secretion. To fix (stabilize) the smell in non-lethal fetid weapons, perfumers have already been used. Skatole or 3-methylindole, produced in the intestines of humans and many animals, is an excellent odor fixer. In low concentrations, skatole has a creamy milky smell, and with further dilution, the aroma turns into a floral one. In a concentrated state, its smell is no different from fecal.
Skunk was one of the first to use mercaptans as a non-lethal weapon.
Foul-smelling compounds are used as in the form of aerosols, but dilution with water and subsequent spraying on disgruntled citizens with a water cannon is more effective. And if you also color the liquid composition accordingly … There are also real samples of hand grenades and grenades for grenade launchers equipped with fetid compositions based on concentrated skatole and mercaptan. The propellant increases the area of action of the ammunition, scattering the smelly substance in an axial or radial direction.
Foul-smelling compounds can be an excellent addition to water cannon tanks.
The second rather rare commodity on the non-lethal chemistry market is super-slippery substances, which are responsible for disabling vehicles and biological objects by depriving them of their ability to move normally. Once again, the Americans were among the first: the National Bureau of Standards (NBS) and the American Society for Testing Materials (Southwest Research Institute) did a great job and eventually created a super-slippery composition. It contains polymer acrylamide with dispersed polyacrylamide, hydrocarbon and water. This whole "how many topic" can be diluted in an oil lubricator, which is used, for example, to lubricate well drills. The long list of substances suitable for creating super-slippery compounds includes various fats, oils, polysilicones (DC 2000), polyglycols (Carbowax 2000), as well as sodium oleate, glycerin and many more complex organic substances. The requirements for such non-lethal weapons are as follows: environmental friendliness, a wide temperature range of use, low toxicity of the composition and a sufficiently high viscosity, suitable for application to inclined surfaces. American chemists plan to use such compounds even against tracked vehicles, however, when applied to hard concrete and asphalt surfaces. Sand with loose earth adsorbs such a liquid know-how, and only a person can slip on it. The most promising substance for creating super-slippery substances that meets all the requirements of the military are pseudoplastics, consisting of two components: a viscous liquid of anionic polyacrylamide and solid particles of the same chemical nature. To bring the composition into a combat state, it is pre-mixed. The result is a homogeneous viscoelastic gel that can withstand vertical loads and does not flow off under the influence of a human sole or car tread. It acquires its properties after 40-60 seconds from the moment of application to the surface. We usually encounter wet ice in nature, which is considered one of the most natural surfaces. However, the American gel is much more insidious - a person with great difficulties can choose a step to move along it, and the car will generally remain in place to grind the surface with tires.
Mobility-inhibiting system in action - depriving the car of the ability to move.
The portable dispenser for the Mobility Denial System.
Based on this development, the US Marine Corps ordered the development of a Mobility Denial System (MDS), which makes it impossible for people and vehicles to move on a hard surface for 6-12 hours at once. Such a gel is sprayed from a wearable device or special military transporters. 23 liter tank is enough to handle 183 m2 areas with an effective spraying range of up to 6 meters. The tank carried by the Hummer is much larger - its 1136-liter water supply and 113.5 kilograms of gel should be enough for 11,150 m at once2 with a spraying range of 30 m. The downside is the need to dilute the concentrate with water, which can be taken from a nearby puddle or other natural reservoir, and this can dramatically reduce the final efficiency due to harmful impurities in the liquid.
The principle of the reversible action of slippery compounds based on polyelectrolytes: a - interaction of an untreated sole with a slippery surface; b - interaction of the sole with a polyelectrolyte of the opposite charge deposited on it with a slippery surface. Based on the material "Non-lethal weapons" edited by V. V. Selivanov, 2017.
Developments that have the opposite effect are also valuable: they decompose a super-slippery substance, which allows soldiers to freely move around the territory treated with "chemistry" such as the Mobility Denial System. Compounds that decompose slippery gels in a few milliseconds are applied to the soles of shoes or to the wheels of equipment. And the fighter, as if magnetized, walks along the super-slippery gel.
