ACS Analyzes Microscopic Views of Hair Interaction


The American Chemical Society has released a study it believes will revolutionize the hair care industry. The society announced at its 236th meeting that it has carried out a microscopic analysis of hair fibers interacting with each other. The researchers find that this information will be beneficial to cosmetic chemists who formulate hair repair products.

The study measured the subtle forces, both physical and chemical, that arise when single hairs slide past each other or are pressed against each other, which differs from the comb force test or volunteer feedback testing that is standard in hair care testing today. 

The researchers analyzed hair by mounting individual hair fibers on a cantilever tip of an atomic force microscope and measuring their interactions as they touch each other. Samples were collected from volunteers that were bleached and ranged from light blond to dark blond in color.The researchers found that hair feels rough and difficult to comb due to mechanical damage to a hair's surface, or cuticle, which creates scaly projections that jut out at perpendicular angles to other hair fibers. When hair fibers slide past each other, these scales create more friction than smooth hairs, causing a rough feel and making hair more difficult to comb. To soften hair, conditioners must contain active agents to smooth-out these scales so that they produce less friction, the researchers say.

Also, hair feels rough and is difficult to comb because chemical changes occur when hair fibers interact. Negative charges build up on the surface of hair that causes repulsion between single hairs. This repulsion causes friction and makes hair rough and difficult to comb. To solve the problem, positively-charged polymers that neutralize the negatively charged surfaces are included in conditioner formula to provide a silky feel to hair.

The next step toward hair repair will be finding the right ratio of beneficial components in a conditioner or shampoo to optimize hair feel.The study was funded by BASF Care Chemicals Division. For more information, visit

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