Spotlight – Hair Dye Chemistry Research Group

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Dye Chemistry Laboratory
College of Textiles
North Carolina State University

Our laboratory specializes in work in the following areas:

• Molecular design and synthesis of dyes and pigments • Dyes having high photostability on hydrophobic fibers • Environmental chemistry of synthetic dyes and pigments • Analytical chemistry of synthetic dyes • Dyes for use in photodynamic therapy (PDT)

Regarding cosmetics research, one member in our laboratory, Tova N. Williams (Ph.D. Candidate in Fiber and Polymer Science with Chemistry Minor), is focusing on the design and synthesis of environmentally-benign alternatives to conventional permanent/oxidative hair dyes. This effort recognizes that hair coloration is a prevalent practice among individuals dissatisfied with the natural, and in many cases, graying appearance of their hair.

Dominating the global market are permanent (long-lasting) hair dyes, desired for their superior resistance to removal by multiple shampooings. Permanent hair dyes are produced inside hair fibers by a reaction between essentially colorless precursors (e.g., p-phenylenediamine) and couplers (e.g., resorcinol), giving rise to oligomeric colorants that are locked inside of hair. Despite their desirable technical properties, there are lingering concerns about the potential toxicity associated with the use of certain hair dye precursors. To help address these concerns, we have synthesized different types of textile dyes as potential permanent hair colorants. These benign alternatives are colorants having a high degree of permanence on hair because they either undergo dimerization inside the fibers or contain a lipophilic group that limits water solubility. The diffusion of these dyes into hair fibers and films and the resultant permanence are currently being investigated.

Dr. Harold S. Freeman, Ciba Professor of Dyestuff Chemistry,
Tova N. Williams, Ph.D. Candidate,, LinkedIn