AIM: To utilize a matrix of single-fiber hair testing methodologies to mechanistically understand the impact of common oiling treatments-coconut oil and mineral oil-on hair strands. Further, the effect of hair twisting-experienced in everyday grooming practices-on hair strength was investigated under different scenarios. METHODS: Study involved multiple surfactant wash cycles of hair swatches with and without overnight hair oil treatments. Instrumental testing was done on strands from hair swatches-Tensile Extension, Torsional Stretching, and Tensile Extension of twisted hair fibers. RESULTS: Differentiation was observed in tensile and torsional testing parameters with 20 wash cycles, while no statistical significance was observed in single wash. However, when we combine the two stresses together by extending the twisted hair strands, a clear differentiation was seen even in single cycle for coconut oil in comparison with mineral oil and surfactant wash. The differentiation in tensile parameters for twisted fibers becomes much more prominent with multiple cycles. Penetration of coconut oil in hair strands makes the fiber core more flexible and thus helps negotiate the torsional stress at the time of extension. CONCLUSIONS: Product benefit discrimination in single-strand testing can be amplified by combining multiple stresses in one testing methodology. Observing the consumer habits and incorporating the torsion component in standard tensile testing of hair helps differentiate the two commonly used hair oiling treatments. Coconut oil was found to significantly increase the tensile strength of twisted fibers owing to its penetration inside hair core.
AIM: To utilize a matrix of single-fiber hair testing methodologies to mechanistically understand the impact of common oiling treatments-coconut oil and mineral oil-on hair strands. Further, the effect of hair twisting-experienced in everyday grooming practices-on hair strength was investigated under different scenarios. METHODS: Study involved multiple surfactant wash cycles of hair swatches with and without overnight hair oil treatments. Instrumental testing was done on strands from hair swatches-Tensile Extension, Torsional Stretching, and Tensile Extension of twisted hair fibers. RESULTS: Differentiation was observed in tensile and torsional testing parameters with 20 wash cycles, while no statistical significance was observed in single wash. However, when we combine the two stresses together by extending the twisted hair strands, a clear differentiation was seen even in single cycle for coconut oil in comparison with mineral oil and surfactant wash. The differentiation in tensile parameters for twisted fibers becomes much more prominent with multiple cycles. Penetration of coconut oil in hair strands makes the fiber core more flexible and thus helps negotiate the torsional stress at the time of extension. CONCLUSIONS: Product benefit discrimination in single-strand testing can be amplified by combining multiple stresses in one testing methodology. Observing the consumer habits and incorporating the torsion component in standard tensile testing of hair helps differentiate the two commonly used hair oiling treatments. Coconut oil was found to significantly increase the tensile strength of twisted fibers owing to its penetration inside hair core.