Viscoelastic characterization of industrial fluids using acoustical rheology. Application to cosmetics and concretes. – RHEACTIF

The material viscoelastic properties assessment covers a wide range of industrial and research problematics, particularly in cosmetics/pharmaceutics, cements/concretes, foods, polymers and petroleum products. It is indeed essential to understand and predict the mechanical dynamic behaviour of industrial products in numerous and not exhaustive applications such as characterizing the viscoelasticity of elastomers, the spreading of a varnish, a paint, a lipstick or a concrete, assessing the fluidity, smoothness, or any other sensory properties in foods or cosmetics, monitoring a polymerisation or jellification process, and so on... Devices have been developed to assess these rheological properties: rheometers (shear viscoelastic modulus in fluids) and Dynamic Mechanical Analysers (DMA, principally adapted to bulk and shear viscoelastic moduli measurements in solids), answer for a large part to these industrial problematics. However, they have some drawbacks, limiting the applications: intrusive measurements, sample contamination or destruction, limited frequency range.
In the acoustics research domain, U930 laboratory developed an innovative wave-coupling method to measure nonlinear bulk viscoelastic properties. First developed to assess the level of microdamage in trabecular bone tissue, this contact-free technique has exhibited a larger range of applications, particularly for assessing nonlinear viscoelastic properties in complex industrial products (fluids, pastes or solids). This technique called acoustical rheology, which is patented and whose feasibility has been demonstrated, can offer a different approach in viscoelastic properties characterisation compared to conventional rheology. A first market study pointed out that several industrial product manufacturers are interested in this innovative approach, especially in cosmetics and cements/concretes domains. This study also show that some technological and scientific issues are not yet fully matured and requires further investigation before transferring the technology to industry, justifying the RHEACTIF proposal. This project gather 4 complementary academic partners: U930, which has developed the acoustical rheology method, UMR7615 and UPR3349 which are experts in conventional rheology, and the technology transfer department (SPVC) of Tours University.
On a technological point of view, we aim to develop an acoustical rheology prototype. RHEACTIF will particularly allow optimizing and integrating the electronics module, other national and European founds being dedicated to the mechanics module optimization. On a scientific point of view, we have to clearly position these new viscoelastic measurements in the routine context of rheology (industrial and academic). Experimentally, acoustical rheology and conventional rheology results will be compared on various fluids materials. Theoretically, an analytical nonlinear viscoelastic model will be developed to identify the pertinent acoustical parameters in terms of rheological characterization. These technological and scientific issues will then be used to test the applicability of the acoustical rheology to industrial products (cosmetics and cementitious materials). In parallel, the economic and legal aspects of the technology transfer will be conducted all along the project.
Supported by the Pôle de compétitivité Cosmetic Valley, this proposal takes place in a larger context, whose finality is to create a start-up (Rheacoustics) emerging from François Rabelais University (Tours). Two seniors searches from U930, Samuel Callé (RHEACTIF coordinator) and Marielle Defontaine, plan to carry out this start-up creation, with the purpose to develop and sell acoustical rheology devices, at the end of the RHEACTIF project.