CHEMISTRY
HAIR
Ms. Trisha Sharma
ASST. Prof. of PG Department of Cosmetology
INTRODUCTION
Most people will wonder as to what has the cosmetogist got to do wuth chemistry ? A professionally trained cosmetologidt has to be much more than a mere technician or a craftsman . W are dealing with matters like hair , skin and chemical . Use of these chemicals produce changes in the hair specially in perming , coloring and straightening . There are new products and theories being put into market every day . Knowledge of these products and theories is usefull to professional as well as the patron . Cosmetologists must know the product they using , the changes that take place , effects of products , desirable and undesirable and how to deal with them .
Chemistry is a science that deals with the composition , structure and properties of matter and how matter changes under different chemical conditions . chemistry is broadly divided into two area .
CHEMISTRY
> ORGANIC CHEMISTRY
> INORGANIC CHEMISTRY
The Chemistry of Hair
Hair is a type of keratin, a fibrous protein that contains sulfur. It is made of living cells that grow inside a tube of dead cells. This is important to know because hair that is damaged inside the protective shaft, or cuticle, cannot heal on its own. Generally, the damage must be trimmed away, and eventually, the hair will grow back. However, in some cases, damaged hair can be treated. To do so, the hairdresser must have a solid understanding of acids and bases.
pH is one of the technical terms you come across frequently in the cosmetic industry. A simple way to think about it is to read it as an indication of how acidic or alkaline your product is, typically on a scale of 1-15. In a cosmetic sense, both ends of the spectrum are classified as being harsh and potentially damaging to skin and as such, cosmetic formulators work to avoid creating products that sit at these extremes.
In technical terms pH is a measure of the number of hydrogen ions in an aqueous solution so, for a product to have a measurable pH there has to be water around for the hydrogen ions to swim around in.
The PH Scale
pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. Water that has more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic.
Since pH can be affected by chemicals in the water, pH is an important indicator of water that is changing chemically. pH is reported in "logarithmic units". Each number represents a 10-fold change in the acidity/basicness of the water. Water with a pH of five is ten times more acidic than water having a pH of six.
Acid
An acid is a chemical species that can be neutralized by a base. Acids are capable of releasing protons or H+ ions in aqueous solutions. An acid can be dissociated into its conjugated base and H+ ions. According to their dissociation strength, there are two types of acids.
The pH of an acid is always below 7. pH 7 is the neutral pH of a solution such as pure water. Very low pH values are given by strong acids and pH values that are near to pH 7 are given by weak acids. However, they have this low pH values since acids give high amounts of H+ ions to the aqueous solution and pH is the logarithm of the inverse of H+ concentration.
Alkaline
Alkaline is a solution that has pH values above 7. This means alkaline solutions show basic properties. Therefore, alkaline solutions can be neutralized by acids. Alkaline solutions are bitter tasting and feel slippery when touched.
An alkaline solution is formed when an alkali is dissolved in water. Alkali refers to any basic hydroxide or a salt of alkali metals or alkaline earth metals. The term alkaline is derived from the metal elements of group 1 and group 2 in the periodic table of elements. The group1 elements are called alkali metals. The group 2 metals are called alkali earth metals.
Balancing pH
Knowing how pH levels affect hair treatments is one thing, but savvy hairdressers should also know how to determine the pH levels of the chemicals they deal with most -- shampoos, conditioners and coloring solutions -- and hair itself. The pH levels of treated hair can vary greatly. For instance, a pH of 2 means the hair will be hard, smooth and brittle, but a pH level of 6 means the hair is hard and smooth, but highly resilient. Testing samples in solutions will tell you how to balance pH levels for optimal results.
HAIR AND SCALP ANALYSIS
Look for cuts, scratches, or open sores; DO NOT proceed with service if skin abrasions or a scalp disease is present. The five most important factors in hair analysis are ___
•texture.
•density.
• porosity.
•elasticity.
•growth direction