27.05.2021 by Milena Riedl

How Shampoo Influences Human Hair

From liquids to highly-filled thermosets to metals and ceramics – all such materials can be measured with the DMA 242 E Artemis. We even evaluate hair samples and the influence of hair care products.

Dynamic Mechanical Analysis (DMA) measures the visco-elastic properties of mostly polymer materials during a controlled temperature and/or frequency program. During the test, a sinusoidal force (ContrainteLa Contrainte est définie par un niveau de force appliquée sur un échantillon d’une section bien définie. (Contrainte = force/surface). Les échantillons qui possèdent une section rectangulaire ou circulaire peuvent être comprimés ou étirés. Les matériaux élastiques comme les élastomères peuvent être étirés jusqu’à 5 à 10 fois leur longueur initiale.stress σ) is applied to the sample (Input). This results in a sinusoidal deformation (strain ε) (Output). Learn more about the DMA measurement principle here!

However, DMA is not only suitable to measure polymer materials. From liquids to highly-filled thermosets to metals and ceramics – all such materials can be measured with the DMA 242 E Artemis. Precise results require optimal adaptation of the test conditions to the materials and applications.

DMA can even be used to study human hair!

Handling hair samples is difficult. However, with the right accessories, DMA allows for studying human hair and evaluating the influence of hair care products like shampoo.

Stress-sweep tests were carried out on a human hair in an air atmosphere and in a mixture of water and shampoo (same hair for both tests). The force was varied from 0.1 N to 1 N and the strain was measured. The plot represents a stress-strain plot for both measurements. The stress-strain plot for both tests shows the difference in the slope of the curves: the hair has higher strain, i.e., it is softer – when in contact with the water-shampoo–mixture than with air.

Figure 1: Softness of human hair (thickness 70 µm and 80 µm) measured in tension mode at 25°C and a frequency of 1 Hz; force varied between 0.1 and 1 N

DMA can also be used to study the effects of bleaching time, environmental relative humidity and cosmetic treatments on different hair types by determining hair viscoelasticity and storage modulus/stiffness.

The right accessories for every research and quality control task

For the measurement above, the DMA 242 E Artemis was equipped with an immersion bath.

Figure 2: Immersion Bath

As each material has its own characteristics, NETZSCH has developed a wide range of sample holders, accessories and measurement modes. Here is a small overview:

More sample holders and accessories are available! Click here to get the full overview!