In space, materials reveal their secrets: COLIS, a new laboratory for studying colloidal gels and glasses in microgravity
A sunscreen that lasts longer, a more stable mayonnaise, a more effective medicine: behind these everyday applications lie complex materials (gels and glasses) whose evolution is still poorly understood. To unravel these mechanisms, researchers at the Politecnico di Milano and the University of Montpellier have designed and developed COLIS, a new laboratory on board the International Space Station dedicated to the study of flexible materials in microgravity.
An innovative laboratory for observing matter outside the influence of gravity
Gels and glasses, materials that are ubiquitous in the pharmaceutical, cosmetic, and food industries, evolve slowly over time. On Earth, gravity subtly but profoundly influences this internal dynamic. By placing these materials in space, scientists can finally isolate and analyze these effects.
The result of a long-standing collaboration between Luca Cipelletti, a physicist at the Charles Coulomb Laboratory (University of Montpellier – CNRS), and Roberto Piazza, a professor at the Politecnico di Milano, COLIS (Colloids in Space) represents a major advance in the eponymous program led by the European Space Agency (ESA), with the support of ASI and CNES.
" Studying these materials in microgravity allows us to isolate the effect of gravity, a silent but decisive force," explains Roberto Piazza. " This understanding is essential for designing more stable formulations, from controlled-release drugs to self-assembled materials."
Transported to the ISS aboard NASA's Cygnus NG-21 cargo spacecraft and built by Redwire Space, COLIS is now fully operational. It analyzes samples of gels and colloidal glasses containing nanoparticles, focusing on the aging processes within them.
Cutting-edge technologies for understanding material stability
COLIS is based on several major innovations:
- Optical dynamic correlation techniques, using speckle patterns to track the internal restructuring of materials,
- Controlled thermal stimulation, enabling the triggering and observation of aging processes.
- Measuring the turbidity of samples and very rapid fluctuations in the light scattered by the sample, capable of early detection of the formation of crystalline phases.
This latest technology will be used by the teams led by Dominique Maes and James Lutsko (Vrije Universiteit Brussel) to study protein crystallization in zero gravity, a crucial step in improving drug stability and optimizing biotechnological processes.
For Luca Cipelletti, " COLIS is the culmination of more than twenty-five years of collaboration with the Politecnico di Milano. Bringing soft materials physics to the ISS represents a scientific and technological challenge that opens up new perspectives in the study of disordered matter."
Initial results: gravity has a stronger influence than expected
Early work carried out by teams in Montpellier and Milan (Luca Cipelletti, Roberto Piazza, Stefano Buzzaccaro, and Alessandro Martinelli) shows that gravity influences the structure and properties of flexible materials much more than previously thought. Its effects persist over time, altering their behavior even in the long term.
" It is surprising to see how a force as familiar as gravity silently shapes the materials we use every day. These observations enable us to improve their stability and, ultimately, the quality of life on Earth," concludes Roberto Piazza.