Adsorption Properties of Hair 340 both induce partial oxidation of hydrophobic cystine disulfide bonds with a commensurate formation of hydrophilic cysteic acid moieties (the reader is referred to Chapter 11). Therefore, the overall hydrophilic nature of the hair is raised by these treatments. It is possible that an increased propensity for swelling may also be a contributing factor. Nonetheless, Figure 6 demonstrates how treating hair with two such chemical treatments still does not have an especially dramatic effect on the water content. In short, differences induced by these relatively aggressive treatments remain rather insignificant in comparison to the afore-mentioned variation in environmental conditions that one encounters on a daily basis. (It appears likely that differences between the present findings and those in Reference 5 relate to the strength of the chemical treatments employed.) Following this thought process further, a mechanism by which shampoos and conditioners may manipulate the equilibrium water content of hair is not readily forthcoming. Figure 5. Water adsorption by wool as function of absolute vapor pressure and temperature