A Method to Measure Oil Penetration into Hair and Correlation to Tensile Strength

AIM: The aim of this study is to identify a new method to measure oil penetration into hair, compare penetration ability of two types of oil: Type 3 hair oil and coconut oil into the hair shaft and explore its correlation to a physical property of hair, tensile strength. MATERIALS AND METHODS: The study utilizes the measurements of two parameters, thickness, and cohesive force to define penetration of oil. The hypothesis was that an increase in hair fiber thickness along with reduction in cohesive force would indicate higher penetration of oil into the hair strand. The tensile strength of hair was then determined by measuring the behavior of treated hair strands while an axial stretching load was applied. RESULTS: In experiment of hair thickness measurement, there was a significant increase in the hair fiber thickness post oil application in both the test oils as compared to baseline (untreated control). However, this increase was higher in hair swatches treated with Type 3 hair oil. For cohesive force measurement, significantly lower force was required for hair swatches treated with Type 3 hair oil when compared to coconut oil. For tensile strength, both test oils exhibited increase versus baseline but increase in tensile strength was significantly more with type 3 hair oil when compared to coconut oil. CONCLUSIONS: The present study shows that conjoint assessment of hair thickness and cohesive force post oil application can be a suitable method to indicate the extent of oil penetration into the hair. Overall, the study indicated the positive influence of oil penetration on hair strength.