Case study – Instrumental method development for the study of cosmetic powder compacts and brush interactions

RHEONIS holds combined expertise regarding instrumentation design, measurement protocols development and physical interacial sciences, that proved useful for this medium-term project.

1. Literature study
2. Functional analysis and brainstorming
3. Mechanical design of a specific expertimental system on rheometry
4. Preliminary testing
5. Study of brush loading protocols and loaded-brush application on paper
6. Development of image processing routines
7. Adjustment and validation on various brushes
8. Systematic study and correlations analysis
9. Data interpretation and conclusions on the internal validity of the test
10. Complementary trials and validation

The testing system is mounted on a rheometer, allowing a fine control of applied constraints and measured responses. Interactions between the compact and the brush (loading and friction) can be quantified, but also the unloading of the brush on an application support. Combined mechanical and optical analysis allow various refinements of the interpretations, leading to a this method to be used as a predictive tool of sensory analysis of powders compact application.