Our coils or curls, whether worn in the natural or relaxed state, have special properties and needs that we must take into consideration. Knowing about coiling behavior and what that means for our fibers will make us all think twice before working with our tresses in a rough manner.
The process of coiling for a hair places a great deal of stress on the fiber, just architecturally. It can’t deal with the same loads of strain that straighter fibers can handle easily. When hair is coiled, the cuticle layers on the outer side of the bend are stretched thinner. The scales on the outer side of the bend are also more susceptible to damage from lifting since they are slightly lifted in that bend to accommodate the angling. The cuticle layers on the inner or underside of a bend are compressed in a smaller area. This makes our fibers unique as well as vulnerable to damage from improper handling.
When our hair is straightened/relaxed, it escapes some of the “downsides” of coiling, but adopts new challenges and downsides. Namely, challenges brought on by the processes we use to straighten our hair ( ex: heat or chemical processes). Each process weakens and stresses the fiber in some way. Even when it’s straightened, and the coily or curly fiber releases into a new, flatter shape- remnants of the hair’s natural cuticle orientation remain. I speak about this in the Science of Black Hair– about how hair tends to not forget itself. It really doesn’t! You often see this expressed as an area of uneveness along the straightened fiber in the coiliest hair types . . .
More on Coiling and Cuticle Fragility and many other topics in the SBH Hair Science Lab: http://blackhairscience.com/forum/