Our lives are consumed by small electronics, like smartphones and smartwatches, from which we demand ever more power. The most intricate components of these devices – the chips, components and chiplets covering the circuit boards inside – are typically assembled by precise robotic grippers. However, the grippers can only manipulate objects above a certain size (around 50-100 microns) and modern components are quickly approaching those limits. Now, a team of researchers from MIT has developed an “electroadhesive” technique that allows them to accurately manipulate even tinier electronic components.

The electroadhesive device, which they call a “stamp,” can place objects as small as 20 nanometers across – a thousand times thinner than a strand of hair, and just an order of magnitude larger than a strand of DNA. The stamp, comprised of a series of ceramic-coated carbon nanotubes on a “tiny brush,” receives voltage, allowing the bristles to attract small particles. When the particles are positioned correctly, the voltage is turned off, and they are no longer attached to the stamp.

“Previous work on [carbon nanotube]-based dry adhesives focused on maximizing the contact area of the nanotubes to essentially create a dry Scotch tape,” said John Hart, the associate professor of mechanical engineering at MIT whose lab developed the technique. “We took the opposite approach, and said, ‘let’s design a nanotube surface to minimize the contact area, but use electrostatics to turn on adhesion when we need it.’”

“Simply by controlling voltage,” he continued, “you can switch the surface from basically having zero adhesion to pulling on something so strongly, on a per unit area basis, that it can act somewhat like a gecko’s foot.”

This technique, Hart said, can be scaled up for manufacturing (nanoscale or microscale), allowing for applications in computer chip manufacturing – but also, perhaps, for applications in cell and tissue manufacturing. (In terms of truly sci-fi applications, the team also imagines applications such as electroadhesive climbing robots.)

“With ever-advancing capabilities of semiconductor devices, an important need and opportunity is to integrate smaller and more diverse components, such as microprocessors, sensors, and optical devices,” Hart said. “Often, these are necessarily made separately but must be integrated together to create next-generation electronic systems. Our technology possibly bridges the gap necessary for scalable, cost-effective assembly of these systems.”

About the research

The research discussed in this article was published in vol. 5, issue 10 of Science Advances as “Soft nanocomposite electroadhesives for digital micro- and nanotransfer printing.” The paper was written by Sanha Kim, Yijie Jiang, Kiera L. Thompson Towell, Michael S. H. Boutilier, Nigamaa Nayakanti, Changhong Cao, Chunxu Chen, Christine Jacob, Hangbo Zhao, Kevin T. Turner and A. John Hart. It can be accessed here.

Read MIT’s reporting on the development here.