Scientists have created an incredible new material that can become smooth or bumpy on demand.
A team of MIT researchers discovered a way to use a 3-D printer to create a new type of soft material that can even be engineered to from complex patterns on its surface that could be used to guide fluids.
The process was developed through computer simulations and involves a material composed of two different polymers with varied degrees of stiffness. In the process, more rigid particles are embedded within a matrix of more flexible polymers. When the material is squeezed it quickly changes from a smooth surface to pattern determined by the spacing of the harder particles.
"Depending on the arrangement of the particles, using the same amount of compression, you can get different surface topographies, including ridges and bumps, along the surface," said MIT graduate student Mark Guttag.
The material could be used to change the aerodynamic resistance or reflectivity of an object, it could also produce microfluidic channels to control the movement of liquids inside a chemical or biological detector. These applications could be useful in camouflage technology, surfaces that repel and attract water, or in regulating the buildup of organisms on surfaces such as ship hulls.
"There are no previous techniques that provide comparable flexibility for creating dynamically and locally tunable and reversible surface changes," Guttag and fellow researcher Mary Boyce, a former MIT professor of mechanical engineering who is now dean of engineering at Columbia University, wrote in their paper.
The current model uses physical pressure to control surface texture, but the same design principles could be used to modify material using temperature change or electric charge stimulation. Embedded particles that are elongated, as opposed to round, could also allow for surfaces that are asymmetrical, potentially leading to a material that is high friction in one direction and slippery in another.
"This is the first-of-its-kind work to create materials with reconfigurable surface texture," said Yonggang Huang, a professor of civil and environmental engineering and mechanical engineering at Northwestern University who was not involved in this work. "The potential practical impact of this work is huge. It can be used in many applications that benefit from the change of surface, such as in optics and tribology [the science of interacting surfaces in motion]."
The findings were published in a recent edition of the journal Advanced Functional Materials.
