Most of microfluidic systems use a fluid flow medium inside the microchannels. This method faces limitations such as the cost of microchannel fabrication, especially for single-use applications, and the need for more equipment to control fluid movement, such as a syringe pump. Thus, in the last decade, digital microfluidic systems are being introduced and used as a serious competitor to traditional microfluidic systems.

In these systems, separate droplets are used instead of a continuous flow of fluid on the surface (without microchannel). The use of droplets in microfluidic systems removes many of the fluid constraints within the microchannel, but on the other hand have limits such as high friction between the droplet and the surface and the possibility of rapid evaporation of the droplet. One solution to this problem is to use a hydrophobic surface to move and control the droplets. This surfaces dramatically reduces friction between the droplet and the surface, but the problem of evaporation, and their compatibility, can impose limitations on the system.
One of the suggested ways to eliminate the mentioned limitations is to use liquid marbles. Liquid marbles are droplets coated with a layer of hydrophobic micro / nano particles. This coatings allows the marbles to roll easily on surfaces (even hydrophilic surfaces) . By using ferrofluid (water fluid containing iron nanoparticles) inside the marbles, the movement of the marbles can be controlled by magnetic field. In this research, one-dimensional motion control of ferrofluid marbles will be studied using a uniform field and two permanent magnets.

Project members: Mohammad Hasan Dabirzadeh, Mohammad Hossein Sarkhosh