On this day in science history: the first U.S. patent for a liquid soap was issued

In 1865, the first U.S. patent for a liquid soap was issued to William Sheppard of New York City (No. 49,561). The patent described his "discovery that by the addition of comparatively small quantities of common soap to a large quantity of spirits of ammonia or hartshorn is thickened to the consistency of molasses, and a liquid soap is obtained of superior detergent qualities." The proportions given were to dissolve one pound of common soap in water or steam, and then add 100-lbs of ammonia such that the liquid thickens to the consistency of molasses. The product was expected to be useful for both domestic and manufacturing purposes. (Hartshorn is an ancient name for an aqueous solution of ammonia).

Decorative soaps, by Phanton at English Wikipedia (Transferred from en.wikipedia to Commons.) [Public domain], via Wikimedia Commons

So, how does soap clean?

Action of soap

When used for cleaning, soap allows insoluble particles to become soluble in water, so they can then be rinsed away. For example: oil/fat is insoluble in water, but when a couple of drops of dish soap are added to the mixture, the oil/fat dissolves in the water. The insoluble oil/fat molecules become associated inside micelles, tiny spheres formed from soap molecules with polar hydrophilic (water-attracting) groups on the outside and encasing a lipophilic (fat-attracting) pocket, which shields the oil/fat molecules from the water making it soluble. Anything that is soluble will be washed away with the water.

Effect of the alkali

The type of alkali metal used determines the kind of soap product. Sodium soaps, prepared from sodium hydroxide, are firm, whereas potassium soaps, derived from potassium hydroxide, are softer or often liquid. Historically, potassium hydroxide was extracted from the ashes of bracken or other plants. Lithium soaps also tend to be hard—these are used exclusively in greases.

Effects of fats

Soaps are derivatives of fatty acids. Traditionally they have been made from triglycerides (oils and fats). Triglyceride is the chemical name for the triesters of fatty acids and glycerin. Tallow, i.e., rendered beef fat, is the most available triglyceride from animals. Its saponified product is called sodium tallowate. Typical vegetable oils used in soap making are palm oil, coconut oil, olive oil, and laurel oil. Each species offers quite different fatty acid content and hence, results in soaps of distinct feel. The seed oils give softer but milder soaps. Soap made from pure olive oil is sometimes called Castile soap or Marseille soap, and is reputed for being extra mild. The term "Castile" is also sometimes applied to soaps from a mixture of oils, but a high percentage of olive oil.

For more information visit:-

https://en.wikipedia.org/wiki/Soap

https://todayinsci.com/8/8_22.htm

http://www.prlabs.co.uk/lab-supplies.php?N=ammonia-buffer-soln&Id=57114

Hangnails!!

A hangnail or agnail (also known as a stepmother's blessing particularly in the Lancashire region) is a corruption of agnail which literally means painful (anguished) nail.

Hangnails can seem rather insignificant in the grand scheme of health problems but they can become infected and lead to a handful of other issues. Fortunately, there are many ways to avoid hangnail hazards.

Hangnails don't have anything to do with your fingernails. Many people confuse hangnails with ingrown nails, a condition in which the corner of your nail grows into the soft skin of your nail bed.  In fact, hangnails are the dry, sometimes brittle triangular-shaped tags of skin around your fingernails that can tear off.  Because there are many different causes of hangnails, everyone gets them occasionally. But chronic, consistent hangnails can lead to bigger problems.

When the skin around your fingernails tears off, it opens the door to infection, especially when you consider all the bacteria your hands are exposed to every day, not to mention dishwater, cold weather and all the other things that dry out your hands in the first place. Fortunately, there are quick and easy ways to prevent hangnails that range from moisturising often to pampering your hands with cuticle soaks and manicures.

If you just can't beat hangnails, there are also easy ways to treat them. Antibacterial lotions can often do the trick, and in more serious cases, a prescription antibiotic might be in order.

Of course, before you can avoid hangnails, you need to know what causes them.

Hangnails are more common during the cold winter months. During the winter, skin dries out really fast which is one of the main causes of hangnails. Anything that can dry out your skin, such as cold winter weather, harsh chemicals or frequent immersion in water can cause hangnails to develop.

If you are a nail biter it can damage your nail bed, which is the skin underneath the actual fingernail and a weak nail bed can result in more hangnails.

Hangnails that aren't properly cared for can result in an infection called paronychia. There are three types of paronychia infection: bacterial, Candidal -- which is a type of yeast -- and fungal

Now that you know how hangnails happen, you're probably wondering how you can stop them before they start.

• Moisturise your hands and your nail beds.  Moisturising your nail beds helps your nails and your cuticles as well which can have a big impact on your overall nail health
• Stop biting your nails.
• Manicure.
• Wear gloves if you are exposed to harsh chemicals or even just soapy water from washing the dishes.

Working in a laboratory can cause a number of hand problems including latex glove allergies.  Make sure you choose the right gloves for your skin and for the job in hand.  Remember to wash your hands properly and moisturise afterwards.

Remember P&R Labpak offers a range of soaps and moisturisers for laboratories so you don’t need to suffer from hangnails!  The new VWR Safety catalogue is also available covering everything you need relating to personal protection, workplace safety, first aid and housekeeping.  Ask for your copy now!

For more information visit:-

http://en.wikipedia.org/wiki/Hangnail

http://health.howstuffworks.com/skin-care/nail-care/health/hangnails.htm

How does Soap Work?

Soap is a curious substance, designed to solve an intriguing problem. Most dirt that will not simply wipe off or be shaken out is in fact some form of fat or grease. In most households the most common cleaning agent is tap water. The problem is that grease and water fall into two different and largely incompatible chemical groups. Drop oil into water, and it will tend to float or form discrete droplets. Pour water into oil and you will see the same effect. Additionally, substances such as salt and sugar that dissolve in water will not dissolve in oil, whereas something like petrol will only float on water but is quite capable of dissolving oil

The Chemistry of Oils

This difference in behaviour is due to the nature of the molecules involved. Water is largely polar, that is, water molecules tend to separate into fragments with opposite electrical charges, one positive and one negative. Chemicals such as table salt that happen to be made up of collections of charged fragments, or ions, find it easy to dissolve in water because the positive ions in the salt are attracted to the negative ions in the water, and vice versa. Similarly, the charged nature of water means that water is a good conductor of electricity.

Fats and oils, on the other hand, tend not to be polar. Their molecules have no particular electrical charge, and so are not attracted to polar substances such as salt. Instead, they prefer to bond with other non-polar substances. Fats and oils tend to be electrical insulators.

Washing Up

This, then, returns us to the washing-up. You have a greasy dish in a bowl of water, but the grease is showing no inclination to dissolve in the water because the water is polar and the grease is not. Attack the grease with a cloth and most of what you achieve is to move it around on the plate, because it is trying to flatten itself against the surface of the plate in a effort to get away from the water molecules.

The soap molecule is a halfway house. It consists of a long strand with an ionic water-loving, grease-repelling group on one end, and a non-polar grease-loving, water-repelling group on the other. If you drop soap into clean water, all the molecules gather on the surface with their water-loving (hydrophilic) ionic ends stuck in the water and their fat-loving (lipophilic) ends waving in the air. Slide a dirty dish in, however, and the lipophilic end of each molecule sticks to the grease as it slips past. As the dish sinks, it takes the soap molecules with it, attached by their heads to the grease but still waving their hydrophilic tails in the water like microscopic tadpoles.

All you have to do now is bash at the dirt with a sponge or cloth, and it can be persuaded to leave the plate, for as it lifts off the surface it becomes insulated from the water as new soap molecules rush in and try to bury their heads in it. The end result is a small blob of grease completely surrounded by a layer of soap molecules, all with their lipophilic heads pointing inwards and their hydrophilic tails pointing outwards. As far as the grease is concerned, all it can see are lipophilic molecules, and as far as the water is concerned, all it can see is a rather large hydrophilic lump.

Eventually, of course, all the soap molecules are used up, and you have to tip out the washing-up water and start again. Pass the tea-towel.

For more information
http://en.wikipedia.org/wiki/Soap#Mechanism_of_cleansing_soaps
http://www.h2g2.com/approved_entry/A283259