But am going to start on the pH scale as I feel it is so very important to understand in relation to shampoo and hair care products in general .
Potential Hydrogen (pH)
Understanding what pH is and how is affects the skin and hair is essential to understanding most of the services that you get in a Salon or that you perform on your own noggin. This will be a brief overview of pH and how it works so then I will go right into pH and shampoos. I'm using a couple textbooks to help me with this, as much as I understand it, I tried writing my own post on the subject and ended up trashing it, my version was so confusing, I gave it to my neighbor to read and he had the most confused look on his face. So we will go with this and see how it works. Its not necessary to fully understand pH, but I would like you to at least have an idea what it is for future reference.
Having the proper pH shampoo makes ALL the difference in the world, as far as tangling and the hairs condition at the end of the shampoo. Many of you have complained about a particular shampoo that is Sulfate-free - thinking the sulfate-free is the cause, which couldn't be farther from the truth. The cause of very tangle-y hair prior to shampooing is:............ improper pH ! the solution? A different shampoo, I'm afraid, is the only answer to that problem.
Water and pH
First we need to understand a bit about ions. An ion is an atom or molecule that carries an electrical charge. Ionization is the separating of a substance into ions. These ions have opposite electrical charges... An ion with a negative electrical charge is an anion and an ion with a positive electrical charge is a cation. Now Ions are at the base of that T3 Dryer that is such a big hit now which I will go into on a different post.
In pure water, some of the water molecules naturally ionize into hydrogen ions and hydroxide ions. The pH scale measures those ions. The hydrogen ion (H+) is acidic..the hydroxide ion (OH) is alkaline. pH is only possible because of this ionization of water. Only aqueous solutions have pH, Non-aqueous solutions (oil and alcohol) do not have pH . . . without water there is no pH.
In pure water, every water molecule that ionizes produces one hydrogen ion and one hydroxide ion. Pure water is neutral because it contains the same number of hydrogen ions as hydroxide ions, meaning it is neither acidic nor alkaline. Pure water is 50 percent acidic and 50 % alkaline.
The pH Scale
The terms "parts hydrogen" or "potential hydrogen" are used to describe pH. In fact, the term pH originates from the French term pouvoir hydrogene , or hydrogen power" and means the relative degree of acidity and alkalinity of a substance. Notice that pH is written with a small p and a capital H ( which represents the hydrogen ion, H+) the symbol pH represents the quantity of hydrogen ions.
The pH values are arranged on a scale ranging from 0 to 14. A pH of 7 indicates a neutral solution, a pH below 7 indicates an acidic solution and a pH above 7 indicates an alkaline solution.
The pH scale is a logarithmic scale. this means that in a pH scale, a change of one whole number represents a tenfold change in pH. A pH of 8 is 10 times more alkaline than a pH of 7...a change of 2 whole numbers indicates a change of 10 times 10 or a one hundredfold change. A pH of 9 is 100 times more alkaline than a pH of 7.
Pure water, with a pH of 7, is 100 times more alkaline than a pH of 5. Since the average pH of hair and skin is 5, pure water is 100 times more alkaline than your hair and skin, even though it has a neutral pH.
Pure water can cause the hair to swell by as much as 20 percent.
pH and Shampoo
Understanding pH levels will help you select the proper shampoo for yourself . Remember, the amount of hydrogen in a solution, determines whether it is more alkaline or acid, is measured on a pH scale that has a range from 0 to 14. A shampoo that is more acid can have a pH rating from 0 to 6.9 , , , a shampoo that is more alkaline can have a pH rating from 7.1 to 14. The higher the pH rating ( more alkaline), the stronger and harsher the shampoo is to the hair. A high pH shampoo can leave the hair dry and brittle. Now why shampoo's don't have pH ratings on them instead of all the other words and BS I will never know, this is the one true scientific - tried and true method of knowing if the shampoo is going to work correctly- there are also some others.
The Chemistry of Shampoos
To determine which shampoo will leave your hair in the best condition, I must explain some of the chemical ingredients regularly found in shampoos. Most shampoo's share many ingredients in common. It is often the small differences in formulation that make one shampoo better than another for a particular hair texture or condition.
Water is the main ingredient in all shampoos and commonly is added at the rate of 30-40% of the formula.
Generally it is not just plain water, but purified or deionized ( ions removed) water. Water is usually the first ingredient listed, which indicates that the shampoo contains more water than anything else. From there on, ingredients are listed in descending order, according to the percentage of each ingredient in the shampoo or formula. This is how it is 'supposed' to be done but I would guess 8 times out of 10 it is not. Regulating hundreds of thousands of beauty products would require every single agency of the government shutting down and helping the FDA, it is virtually impossible.
The second ingredient that most shampoos have in common is the primary surfactant or base detergent. These 2 terms, surfactant and detergent mean the same thing: cleansing or "surface active" agent.
A surfactant molecule has two ends" a hydrophilic or water-attracting "head" and a lipophilic or oil-attracting "tail". During the shampoo process, the hydrophilic head attracts water, and the lipophilic tail attracts OIL. this creates a push-pull process that causes the oils, dirt, and deposits to roll up into little balls that can be lifted off in the water and rinsed from the hair ( see the photos).
Other ingredients are added to the base surfactants to create a wide variety of shampoo formulas. Moisturizers, oils, proteins, preservatives, foam enhancer's and perfumes are all standard components of shampoos.