K-Y Jelly is an awesome lubricant that is unparalleled by other lubricants. It is used at hospitals and other practical uses (like making Arnold Schwarzenegger glow in the dark green blood) or wrestling. One scientific use is to use it as a gonioscopic fluid. It is like the Duct tape of lubricants. However, most people use it just for sex. Johnson & Johnson caught onto this trend and started making this into a significant brand. Here are a bunch of commercials that are funny and it all started with a good lubricant that reduced the skin's surface tension....
-Y Jelly was made by Johnson & Johnson. glycerol BP, propylene glycol BP, hydroxyethyl cellulose,
hydrogen phosphate buffer, and water. Although it would seem desirable to use natural products like mud, cream corn, Vaseline or other products they are not so good.. One thing that K-Y Jelly does really well is to "surface tension" of the skin without being appreciably absorbed. Vegetable oils do make the skin feel slippery, but do so weakly as compared to glycerin based, (water based) lubricants. The surface tension of lubricants like K-Y Jelly and ability to reduce the surface tension of the things skin is really important.
There is a actually a theory called lubrication theory in fluid dynamics which describes the flow of fluids (liquids or gases) in a geometry in which one dimension is significantly smaller than the other. The interior flow parameter needs to be known and the pressure distribution of volume need to be solved. In the case of K-Y Jelly on skin however a free film lubrication theory is used. This theory involves one of the surfaces to be a free surface and the surface tension is a dominant factor in understanding the position of this free surface. I do not understand the last sentence I just wrote.....and should look up more on this theory.
Anyways, I know that when you use K-Y jelly you will notice that it makes you feel like your skin is more wet and allows a thin film to cover whichever part you are using the K-Y jelly with. This allows less Van der Waals, hydrogen bonds and less adjoining forces to come in contact with the skin surface.
One excellent instrument to help test the surface tension to make better lubricants would be the EZ-Pi Plus. It offers both static and dynamic surface tension to help researchers make the best formulations. This and other instruments are used at 4/5 of the major cosmetic and toiletry companies.
