Final answer:
The strength of a permanent wave is based on the disruption and reformation of disulfide bonds in hair strands, facilitated by chemicals like ammonium thioglycolate.
Step-by-step explanation:
The strength of any permanent wave is based on the disruption and reformation of disulfide bonds in hair strands. The strength of a permanent wave is based on the disruption and reformation of disulfide bonds in hair strands, facilitated by chemicals like ammonium thioglycolate.
During the permanent wave process, a chemical, usually ammonium thioglycolate, is applied to the hair, which reduces and breaks some of the disulfide cross-links. This allows the hair to take on a new shape. When the hair is neutralized, new disulfide bonds are formed, which stabilize the hair in its new shape and give the permanent wave its strength and longevity.