Final answer:
Chemical solutions alter hair's curl pattern by breaking and reforming disulfide bonds in the keratin structure, resulting in a permanent alteration. Temporary changes occur through disruptions in hydrogen bonds, which are less stable. This chemistry-driven process redefines the hair's shape until new growth occurs.
Step-by-step explanation:
Chemical Solutions and Hair Structure
Chemical solutions used in hair treatments like perming and straightening alter the hair's natural curl pattern by breaking and reforming the disulfide bonds within the hair's keratin structure. The process typically involves applying a reducing agent, such as ammonium thioglycolate, to the hair. This agent disrupts the disulfide bonds, allowing the hair to take on a new shape when wrapped around forms or straightened. Following this, an oxidizing agent like hydrogen peroxide, referred to as the neutralizer, is used to reform these disulfide bonds, securing the hair in its new shape. The result is a permanent alteration of the hair's curl pattern, lasting until the hair grows out.
Temporary waves are achieved through a similar disruption of hydrogen bonds caused by water molecules which also affects the hair's shape. However, the change is not permanent and reverts once the hair gets wet again. In contrast, the permanent waving process solidifies new hair shapes for an extended duration due to the reforming of disulfide bonds.