Magnetic Actuation of Drops and Liquid Marbles Using a Deformable Paramagnetic Liquid Substrate

Area of Science:

• Fluid dynamics
• Magnetohydrodynamics
• Microfluidics

Background:

• Traditional magnetic actuation of liquids is inefficient for diamagnetic fluids like water and oil without additives.
• Existing methods often require magnetosensitive particles, limiting applications.
• A need exists for additive-free, efficient magnetic manipulation of diverse liquid entities.

Purpose of the Study:

• To develop a new, additive-free strategy for magnetically controlling discrete liquid entities.
• To demonstrate the transport and manipulation of various liquids using a paramagnetic substrate.
• To explore the potential for complex trajectories and on-demand fusion of liquid drops.

Main Methods:

• Utilized a paramagnetic liquid as a deformable substrate.
• Employed a small permanent magnet (approx. 50 mT) to direct the motion of floating liquid entities.
• Tested transport of various liquids, including diamagnetic (water, oil) and nonmagnetic types.

Main Results:

• Successfully demonstrated magnetic control and transport of diverse liquid entities, including naked drops and liquid marbles.
• Achieved efficient manipulation using a moderate magnetic field without additives.
• Showcased reliable complex trajectory control and on-demand drop fusion, indicating multiplexing potential.

Conclusions:

• The developed paramagnetofluidic method offers an efficient, additive-free approach to magnetic liquid manipulation.
• This technique is compatible with a wide range of liquids and requires no complex equipment or external power.
• The method aligns with the development of robust, low-cost analytical and diagnostic fluidic devices.