Final answer:
To cause the least swelling of the hair cuticle during a permanent wave, a solution with a lower pH should be used, as higher pH solutions create more cuticle swelling. Temporary waves, which involve hydrogen bonds rather than disulfide bonds, are less damaging to the cuticle.
Step-by-step explanation:
The question pertains to which permanent wave will cause the least swelling or opening of the hair cuticle. In the permanent wave process, disulfide bonds in the hair are temporarily broken, allowing hair to take on a new shape. A basic reducing substance, such as ammonium thioglycolate, is often used in this process.
However, to minimize cuticle swelling, a permanent wave solution with a lower pH may be preferable as it would be less harsh, resulting in less opening of the cuticle. Such a solution would be gentler compared to an alkaline permanent wave solution, which would cause more swelling and opening of the cuticle.
On the other hand, temporary waves involve the disruption of hydrogen bonds when the hair gets wet. As the hair dries, new hydrogen bonds are formed, allowing the hair to maintain a new shape temporarily without the same amount of cuticle damage seen in alkaline permanent waves.