Wettability of hair
Contact angle as a measure for the effect of hair-care products
Hair-care products are made for specific applications and adapted for different hair types. At every application step, the care product encounters a certain surface character of the hair and leaves the surface changed. Our measuring instruments enable the surface of bunches of hair or even individual hairs to be analyzed. They therefore help to match the product specifically to the particular nature of the hair or application.
Measuring wettability using the single fiber method
Human hair is enclosed by a hydrophobic protective layer. The expectation when washing their hair is to remove contamination, which is also hydrophobic, but to leave the hair protected and durable again. Hair conditioners in turn change the surface by enclosing it in a smoothing coating.
The success of a hair-care application and the change to the surface are measured by means of the wettability of the hair before and after the application with the help of single-fiber contact angle technology. A Force Tensiometer fitted with a highly sensitive force sensor is capable of detecting the small changes in the wetting forces before and after the application of a care product.
Optical contact angle measurements on hair
Optical contact angle measurements with drops in the picoliter range using an instrument with microscope optics provide an alternative method for investigating wettability. These droplets are applied to the approximately 0.1 mm thick hair and subjected to drop shape analysis. At the same time, the high magnification also makes rough and inhomogeneous regions of the hair visible.
