RRI Breakthrough Reveals Hidden Behavior of Gels and Shampoos
Scientists at the Raman Research Institute (RRI) have developed a novel device that visualizes the internal dynamics of thick fluids like gels and shampoos, offering industries a way to optimize production and reduce energy waste.
Key Takeaways
- New device combines force measurement with real-time microscopic imaging.
- Reveals chaotic “sawtooth” force patterns in non-Newtonian fluids.
- Enables better design of industrial and consumer products.
The Challenge with Everyday Fluids
Many common substances, from cosmetic gels to oil-drilling fluids, are non-Newtonian. Unlike water, their internal structure constantly rearranges under movement, affecting everything from oil extraction to how shampoo spreads. Previously, scientists lacked a reliable method to observe these changes in real time.
How the New Device Works
The RRI team built a customized setup inside a standard rheometer. A needle-like probe moves through fluid held between two cylinders, allowing simultaneous measurement of force and real-time microscopic observation.
Observing Chaotic Fluid Behavior
The combined measurements revealed striking fluid behavior. At low speeds, the fluid behaved like water with constant force. Beyond a certain velocity, the force began to oscillate in a jagged “sawtooth” pattern, indicating chaotic motion where the fluid repeatedly builds and releases resistance.
High-speed imaging showed this was caused by a “wake” forming behind the probe. This tail-like structure stretches until it suddenly snaps, causing the force to drop, after which the fluid reforms and the cycle repeats.
“The design of the custom-built set-up provides the flexibility and freedom to explore many aspects in the context of probe motion to access, measure and reveal the behaviour of complex materials,” said Abhishek Ghadai, PhD scholar at RRI and lead author of the research.
Beyond Traditional Measurements
The study demonstrates that traditional bulk measurements, which treat fluids as uniform, cannot capture this behavior. Instead, local structures—tiny, constantly changing clusters within the fluid—actually control how objects move through it.
“Our study highlights the importance of investigating the mechanics of materials over different length scales to understand complex materials for applications and fundamental scientific interests,” said Prof. Sayantan Majumdar, faculty member at RRI, who led the project.
Industrial Applications and Benefits
This method can help industries fine-tune materials more efficiently. Applications include improving drilling chemical flow in oil extraction and creating cosmetic products with more consistent spreading. Understanding exactly how fluids thicken, thin, or resist movement enables better machine tuning for smoother production and more predictable consumer products.
