Adsorption Properties of Hair 344 rollers) that remove water, induce a stronger bonding network, and allow for short-term style creation. However, as outlined above, upon completion of this process, hair will immediately begin to re-adsorb a water content dictated by the current environmental conditions. 2) Experimental approaches : Historically, adsorption experiments have been performed by either volumetric or gravimetric means. In earlier times, gravimetric experiments were rather tedious to perform as they involved constantly recording the weight of a sample while manipulating the relative humidity of the atmosphere using saturated salt solutions. Thankfully, modern day laboratory instrumentation has considerably improved the ease with which these experiments can now be performed, with data from electronic balances being continuously recorded and stored while mass flow controllers manipulate dry and moist air flows to accurately and precisely control the relative humidity. Thus, not only are experiments now much easier to perform, but there is significantly more flexibility, allowing for more complex experiments to further probe the interaction of water with hair. Today this equipment is often termed Dynamic Vapor Sorption (DVS). All results shown herein were obtained using a DVS-1, or an Intrinsic DVS from Surface Measurement Systems (SMSNA, Allentown, Pa). The heart of the equipment is a very sensitive microbalance which allows continuous monitoring of the sample weight as a function of precise manipulation of the relative humidity. In addition, the whole unit resides in an incubator that allows for accurate temperature control. A schematic of this equipment is shown in Figure 9. In order to generate isotherms such as those shown in Figure 1, the sample is first allowed to sit at the initial condition (0% RH) for a prolonged period of time to allow total de-gassing of removable water. The balance is then tarred, and the instrument takes control of the humidity while constantly recording the weight of the sample. Experiments typically involve stepping through a series of relative humidity settings and evaluating the equilibrium moisture content at each condition see Figure 10. This state may be