Universal and economical experimental platform for colloidal mixing lab-on-chip in parabolic flight

This study presents an economical experimental platform designed to investigate colloid and emulsion mixing under parabolic flight conditions. The compact 20 kg system integrates a modular fluidic device with real-time imaging capabilities to enable the observation of fluid interactions at the millimeter scale. The platform focuses on safety, like a double containment system, while remaining accessible for quick experimental modifications. Experiments using four distinct colloids, Thailand Lunar Simulant (TLS-01A), emulsions with Span 80 (50% v/v) and Tween 80 (10% v/v), and a control without additives, enabled analysis of surface tension and particle effects on mixing behavior. Through 29 experimental trials during parabolic flight cycles, each with approximately 20 s of microgravity, the system captured fluid dynamics at 240 frames per second. The platform enables future research to observe effects of surfactant and mixer geometry in real-world scale, with potential for improvements in automation and imaging capabilities. Using a simple measure of color distribution entropy, the Span 80 sample exhibited the highest degree of mixing, with a 24.2% improvement over the microgravity control and a 19.4% increase relative to ground-based Span sample. © The Author(s) 2025.