Washington, Jan 6 (IANS) The development of a new magnetic ‘ferropaper’ has enabled scientists to make tiny motors for surgical instruments or even miniature speakers.
Magnetic ‘ferropaper’ is made by impregnating ordinary paper, even newsprint, with a mixture of mineral oil and “magnetic nanoparticles” 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, Purdue University (PU) professor of electrical and computer engineering and biomedical engineering, who led the development team.

“Because paper is very soft, it won’t damage cells or tissue,” Ziaie said. “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.

The magnetic ferropaper might be used to make low-cost “micromotors” for surgical instruments, tiny tweezers to study cells and miniature speakers.

As the technique is inexpensive and doesn’t require specialised lab facilities, it could be used in community colleges and high schools to teach about micro robots and other engineering and scientific principles, Ziaie said.

The magnetic particles, which are commercially available, have a diameter of about 10 nanometres, or billionths of a metre. Ferro is short for ferrous, or related to iron.

“You wouldn’t have to use nanoparticles, but they are easier and cheaper to manufacture than larger-size particles,” Ziaie said. “They are commercially available at very low cost.”

The researchers used an instrument called a field-emission scanning electron microscope to study how well the nanoparticle mixture impregnates certain types of paper.

“All types of paper can be used, but newspaper and soft tissue paper are especially suitable because they have good porosity,” Ziaie said, according to a Purdue release.

The findings will be presented during the 23rd IEEE International Conference on Micro Electro Mechanical Systems Jan 24-28 in Hong Kong.