To date, contributions from this author have focused on attributes and scientific parameters primarily associated with shampoos and conditioners. This contribution switches focus to quantifying technical characteristics associated with hair styling products. There are two general classifications of such products: those that help with style creation, and those that prolong the style. The benefits of conditioner-induced surface lubrication have been heralded in a previous contribution; but there is a downside when it comes to styling, as the smooth surface inhibits the ability to effectively grip and manipulate the hair with a brush. Both mousses and hair gels aid with this issue, and represent the primary product forms for facilitating style creation. Meanwhile, hair sprays (both aerosol and non-aerosol) are generally used to promote longevity after the styling process.
Technically, the benefits of both styling and hold stem from the presence of water-soluble polymers in formulations. In mousses and gels, these polymers induce a rheology that creates cohesion, and possibly a degree of tackiness, to allow hair to be gripped with the brush. In hair sprays, aerosolized droplets of polymer solutions deposit on the hair that, after evaporation of the solvent, “glue” the hair array or style together through the creation of “spot welds” and “seam welds” between fibers.
Hair spray has been in the crosshairs of regulatory bodies seeking to minimize volatile organic compound (VOC) emissions. This goal created a great deal of R&D activity in the mid-to-late 1990s, as ingredient manufacturers and end product companies expended considerable efforts in attempt to maintain product performance under trying new conditions. Those involved in the category at the time will recall a proliferation of new polymers and formulation strategies that necessitated the need for comprehensive technical characterization. Herein and in a future contribution, the techniques this author found particularly worthwhile toward this proliferation, and that continue to remain useful today, will be described.