Background

Microfluidics provide a versatile platform to create designer emulsion drops, soft particles, and core-shell capsules for a variety of consumer product industries. Properties of the fabricated materials, including droplet surface tension and soft particle elasticity, are key to determining the success of the produced materials for their intended use. Further, surface tension and elasticity determine the stability of droplets and particles in downstream processing. Surface tension and elasticity in microfluidic devices can also provide insight into the physical and chemical properties of multiphase fluids. Current microfluidic devices are unable to measure these material properties in situ. Rather, ex situ techniques are currently used, like the pendant drop technique to measure the surface tension of a droplet and indentation techniques that measure elasticity. Both of these ex situ techniques can measure only one droplet or particle at a time, and require collection of the fabricated material and removal from the microfluidic device. However, it has also been found to be difficult to remove droplets or particles out of fluidic systems for measurement, because they can be unstable and lead to aggregation, adhesion to channel walls, or coalescence. In situ measurement of material properties could both eliminate the need for ex situ characterization and also identify fabrication conditions to achieve maximum stability of the product formulation. A device that can measure the material properties of droplets, particles and capsules in situ across a range of conditions could have a significant impact across multiple industries including pharmaceutical, food, and personal care.

Technology Overview

This novel device developed by Northeastern researchers measures material properties of droplets and particles in situ and in line with fluidic fabrication techniques. To overcome issues associated with extracting droplets for measurements, this device can be incorporated into commercially available fluidic device designs. Studies conducted using this novel tensiometer have validated results for surface tension measurements against a standard of the pendant drop technique. The device has been shown to work well in pressure-driven flow conditions, as well as in high throughputs, with high concentrations of droplets flowing near walls. This poses a great advantage when compared to existing technologies in the market that can only operate in a narrow window of conditions involving limitations on the cross-sectional shape of the channel, flow field, dilution, and droplet location. This novel device’s ability to measure droplets’ characteristics in a high throughput environment provides an additional advantage in that it helps reduce material waste. Future developments to this disruptive and revolutionary device include expanding its abilities to measure elastic properties of soft particles and core-shell capsules.

Benefits

• Ability to measure droplet and in the future, particle characteristics, in varied and more versatile flow types
• High throughput in-situ measurement of concentrated samples
• Droplets that are measured do not have to be far from the channel walls, and can be measured in pressure-driven flow regions

Applications

• Combination usage with micro- and macro-fluidic droplet and particle makers
• Potential use for measuring elastic properties of designer particles other than droplets, including capsules
• In pharmaceutical, food, and personal care industries that employ emulsions and particulate formulations

Opportunity

Seeking licensee/industry partner/funding