Paper-based motors

Purdue University researchers claim to have created a magnetic ‘ferropaper’ that could be used to make low-cost micromotors in applications such as surgical instruments, tiny tweezers to study cells and miniature speakers.

According to Purdue, the material is made by impregnating ordinary paper with a mixture of mineral oil and particles of iron oxide. The nanoparticle-laden paper can then be moved using a magnetic field.

‘Paper is a porous matrix, so you can load a lot of this material into it,’ said Babak Ziaie, a professor of electrical and computer engineering and biomedical engineering. ‘Because paper is very soft, it won’t damage cells or tissue. It is very inexpensive to make. You put a droplet on a piece of paper and that is your actuator, or motor.’

Once saturated with this ‘ferrofluid’ mixture, the paper is coated with a biocompatible plastic film, which makes it water resistant, prevents the fluid from evaporating and improves mechanical properties such as strength, stiffness and elasticity.

Findings from this research will be detailed in a research paper being presented during the 23rd IEEE International Conference on Micro Electro Mechanical Systems on 24-28 January in Hong Kong.