4 research outputs found
Microfluidic Tensiometry Technique for the Characterization of the Interfacial Tension between Immiscible Liquids
The interfacial tension
between two immiscible fluids is of critical
importance for understanding many natural phenomena as well as in
industrial production processes; however, it can be challenging to
measure this parameter with high accuracy. Most commonly used techniques
have significant shortcomings because of their reliance on other data
such as density or viscosity. To overcome these issues, we devise
a technique that works with very small sample quantities and does
not require any data about either fluid, based on micropipette aspiration
techniques. The method facilitates the generation of a droplet of
one fluid inside of the other, followed by immediate in situ aspiration
of the droplet into a constricted channel. A modified Young–Laplace
equation is then used to relate the pressure needed to produce a given
deformation of the droplet’s radius to the interfacial tension.
We demonstrate this technique on different systems with interfacial
tensions ranging from sub-millinewton per meter to several hundred
millinewton per meter, thus over 4 orders of magnitude, obtaining
precise results in agreement with the literature solely from experimental
observations of the droplet deformation
Microfluidic Tensiometry Technique for the Characterization of the Interfacial Tension between Immiscible Liquids
The interfacial tension
between two immiscible fluids is of critical
importance for understanding many natural phenomena as well as in
industrial production processes; however, it can be challenging to
measure this parameter with high accuracy. Most commonly used techniques
have significant shortcomings because of their reliance on other data
such as density or viscosity. To overcome these issues, we devise
a technique that works with very small sample quantities and does
not require any data about either fluid, based on micropipette aspiration
techniques. The method facilitates the generation of a droplet of
one fluid inside of the other, followed by immediate in situ aspiration
of the droplet into a constricted channel. A modified Young–Laplace
equation is then used to relate the pressure needed to produce a given
deformation of the droplet’s radius to the interfacial tension.
We demonstrate this technique on different systems with interfacial
tensions ranging from sub-millinewton per meter to several hundred
millinewton per meter, thus over 4 orders of magnitude, obtaining
precise results in agreement with the literature solely from experimental
observations of the droplet deformation
Direct Visualization of Spatiotemporal Structure of Self-Assembled Colloidal Particles in Electrohydrodynamic Flow of a Nematic Liquid Crystal
Characterization of spatiotemporal
dynamics is of vital importance
to soft matter systems far from equilibrium. Using a confocal laser
scanning microscopy, we directly reveal three-dimensional motion of
surface-modified particles in the electrohydrodynamic convection of
a nematic liquid crystal. Particularly, visualizing a caterpillar-like
motion of a self-assembled colloidal chain demonstrates the mechanism
of the persistent transport enabled by the elastic, electric, and
hydrodynamic contributions. We also precisely show how the particles’
trajectory is spatially modified by simply changing the surface boundary
condition
Direct Visualization of Spatiotemporal Structure of Self-Assembled Colloidal Particles in Electrohydrodynamic Flow of a Nematic Liquid Crystal
Characterization of spatiotemporal
dynamics is of vital importance
to soft matter systems far from equilibrium. Using a confocal laser
scanning microscopy, we directly reveal three-dimensional motion of
surface-modified particles in the electrohydrodynamic convection of
a nematic liquid crystal. Particularly, visualizing a caterpillar-like
motion of a self-assembled colloidal chain demonstrates the mechanism
of the persistent transport enabled by the elastic, electric, and
hydrodynamic contributions. We also precisely show how the particles’
trajectory is spatially modified by simply changing the surface boundary
condition