Over the past few years several companies have launched breathable nail polishes and have made various claims that they are halal or permissible for the purposes of ablution (wudhu) as they supposedly allow for water to pass through them to the nail bed. However, the scientific nature of the experiments done to test these polishes has often been flawed for several reasons leading to false positive results (ie the nail polish appears to allow water to go through when in fact the experiment itself is flawed). So when doing the permeability tests on any of your favorite brands, make sure you’re aware of the following experimental errors that may be giving you false results.
Rubbing water drops with fingers on an absorbent surface
The most common method of doing the permeability test with breathable nail polish is placing a few drops of water on the dry polish and then rubbing the water for several seconds. However, from a scientific perspective, this method of experimentation may lead to false results for a couple of reasons. Firstly, contamination of the water and or nail polish may occur if the experimenter is not wearing any gloves. If you’ve seen any of the online videos, you’ll notice all the experiments have been done bare handed. It may also lead to false results due to the different and unmeasured levels of pressure used per experiment. Although each company recommends rubbing the polish for different amounts of time, none of them explain how much pressure should be used while rubbing the nails. Finally, the addition of friction may also rub away fibers of the absorbent surface and nail enamel causing micro abrasions (tiny holes) in the surface of the nail polish. Technically, if you rubbed hard enough, you could burn a hole through the surface of any paper product. The creation of these micro abrasions may allow water to pass through creating a false positive result.
Testing the permeability with henna (mehndi)
Using henna on the surface of the nail polish and allowing it to dry can result in a false positive result as the dye may show up on the surface of the nail once the nail polish is removed. Henna dye is composed of a molecule called lawsone that is almost insoluble in water (water only holds it, but won’t dissolve it). This molecule is strongly attracted to proteins in the skin, nails, and hair. Therefore when applied on the surface of nail polish, it may penetrate through nail polish, but will leave behind any water or moisture that it was mixed with on the surface of the nail. Unless the nail polish is fully water permeable, the water molecules will not permeate through with the henna.
Now that you understand why the breathable formulas are not really permeable, you may be wondering though why some tests failed with water permeable formulas. There have been some alternative experiments done with water permeable nail polish that have failed due to the following reasons:
Water Permeability Test does not work on hard surfaces (surfaces other than paper towel or absorbent materials)
When performing the Water Permeability Test, an absorbent surface is necessary in order to demonstrate the flow of water in one direction. On a hard or non-absorbent surface, the water may pass through water permeable nail polish, however, the water flows in both directions, hence giving the impression that the water is simply sitting on the surface of the nail polish.
Water Permeability Test does not work if the nail polish is peeled off a surface and placed on an absorbent surface
Some attempts have been made to perform the Water Permeability Test by using a layer of nail polish that has been peeled off a hard surface and then placed on an absorbent surface. This method creates a false negative due to the contraction of the peeled nail polish. Think of the nail polish as a balloon with holes, stretched over a rough surface. When stretched, the holes become large (hence allowing water molecules to pass through. However, once the nail polish is peeled off of a surface (such as glass or plastic) the nail polish contracts and the water channels/pores of the nail polish contract and miniaturize. This prevents the water from passing through the nail polish.
Water Permeability Test does not work on paper, napkin, or coffee filter
The use of these surfaces for the Water Permeability Test may result in false positives due to the nature of the material. Various paper based surfaces can be coated with water repellent chemicals such as starch. This is done in order to increase the shelf life of the product and to increase the tensile strength. For this reason, for the purposes of performing the Water Permeability Test it is advised to use untreated paper towel.
When it comes to halal nail polish, there’s always going to be various arguments as to what is and what isn’t permissible. The good thing is that we live in the age of information, and it’s always at our fingertips. So when in doubt - ALWAYS ASK. Whether it be your local Imam, your high school science teacher, or even the companies themselves that make these products, you should always be fully satisfied with the answers to your questions and concerns.