The goal of the Atoms to Product (A2P) program is to develop the technologies and processes required to assemble nanometer-scale pieces, whose dimensions are near the size of atoms, into systems, components, or materials that are at least millimeter-scale in size. Many common materials exhibit unique and very uncommon physical characteristics when fabricated at nanometer-scale. These “atomic-scale” behaviors have potentially important defense applications, including quantized current-voltage behavior, dramatically lower melting points and significantly higher specific heats, for example. The challenge is how to retain the characteristics of materials at the atomic scale in much larger “product-scale” (typically a few centimeters) devices and systems.
While assembly is the primary focus of A2P, the second key program interest is the exploitation of unique nanometer-scale characteristics. Systems, components, or materials that result from A2P will leverage the unique material properties, miniaturization, 3-D architectures, and heterogeneity (material and geometric) enabled by nanometer-scale assembly.
DARPA recently selected 10 performers to tackle this challenge:
Zyvex Labs, Richardson, Texas;
SRI, Menlo Park, California;
Boston University, Boston, Massachusetts;
University of Notre Dame, South Bend, Indiana;
HRL Laboratories, Malibu, California;
PARC, Palo Alto, California;
Embody, Norfolk, Virginia;
Voxtel, Beaverton, Oregon;
Harvard University, Cambridge, Massachusetts; and
Draper Laboratory, Cambridge, Massachusetts.
“The ability to assemble atomic-scale pieces into practical components and products is the key to unlocking the full potential of micromachines,” said John Main, DARPA program manager. “The DARPA Atoms to Product Program aims to bring the benefits of microelectronic-style miniaturization to systems and products that combine mechanical, electrical, and chemical processes.”
The program calls for closing the assembly gap in two steps: From atoms to microns and from microns to millimeters. Performers are tasked with addressing one or both of these steps and have been assigned to one of three working groups, each with a distinct focus area.
Image caption: Microscopic tools such as this nanoscale “atom writer” can be used to fabricate minuscule light-manipulating structures on surfaces. DARPA has selected 10 performers for its Atoms to Product (A2P) program whose goal is to develop technologies and processes to assemble nanometer-scale pieces—whose dimensions are near the size of atoms—into systems, components, or materials that are at least millimeter-scale in size. (Image credit: Boston University)
Nanometer to Millimeter in a Single System – Embody, Draper and Voxtel
Current methods to treat ligament injuries in warfighters—which account for a significant portion of reported injuries—often fail to restore pre-injury performance, due to surgical complexities and an inadequate supply of donor tissue. Embody is developing reinforced collagen nanofibers that mimic natural ligaments and replicate the biological and biomechanical properties of native tissue. Embody aims to create a new standard of care and restore pre-injury performance for warfighters and sports injury patients at a 50% reduction compared to current costs.
Radio Frequency (RF) systems (e.g., cell phones, GPS) have performance limits due to alternating current loss. In lower frequency power systems this is addressed by braiding the wires, but this is not currently possibly in cell phones due to an inability to manufacture sufficiently small braided wires. Draper is developing submicron wires that can be braided using DNA self-assembly methods. If successful, portable RF systems will be more power efficient and able to send 10 times more information in a given channel.
For seamless control of structures, physics and surface chemistry—from the atomic-level to the meter-level—Voxtel Inc. and partner Oregon State University are developing an efficient, high-rate, fluid-based manufacturing process designed to imitate nature’s ability to manufacture complex multimaterial products across scales. Historically, challenges relating to the cost of atomic-level control, production speed, and printing capability have been effectively insurmountable. This team’s new process will combine synthesis and delivery of materials into a massively parallel inkjet operation that draws from nature to achieve a DNA-like mediated assembly. The goal is to assemble complex, 3-D multimaterial mixed organic and inorganic products quickly and cost-effectively—directly from atoms.
Optical Metamaterial Assembly – Boston University, University of Notre Dame, HRL and PARC
Nanoscale devices have demonstrated nearly unlimited power and functionality, but there hasn’t been a general- purpose, high-volume, low-cost method for building them. Boston University is developing an atomic calligraphy technique that can spray paint atoms with nanometer precision to build tunable optical metamaterials for the photonic battlefield. If successful, this capability could enhance the survivability of a wide range of military platforms, providing advanced camouflage and other optical illusions in the visual range much as stealth technology has enabled in the radar range.
Boston University's first A2P milestone will be to assemble two types of sub-200 nanometer gratings into 210 micron assemblies that maintain their nanoscale properties. That step will take 12 months of the 3-year program. The second step will be to assemble those micro-scale subassemblies into millimeter-sized products that continue to maintain the quantum effects, as well as the lower melting points and higher specific heats of nanoscale assemblies.
The University of Notre Dame is developing massively parallel nanomanufacturing strategies to overcome the requirement today that most optical metamaterials must be fabricated in “one-off” operations. The Notre Dame project aims to design and build optical metamaterials that can be reconfigured to rapidly provide on-demand, customized optical capabilities. The aim is to use holographic traps to produce optical “tiles” that can be assembled into a myriad of functional forms and further customized by single-atom electrochemistry. Integrating these materials on surfaces and within devices could provide both warfighters and platforms with transformational survivability.
HRL Laboratories is working on a fast, scalable and material-agnostic process for improving infrared (IR) reflectivity of materials. Current IR-reflective materials have limited use, because reflectivity is highly dependent on the specific angle at which light hits the material. HRL is developing a technique for allowing tailorable infrared reflectivity across a variety of materials. If successful, the process will enable manufacturable materials with up to 98% IR reflectivity at all incident angles.
PARC is working on building the first digital MicroAssembly Printer, where the “inks” are micrometer-size particles and the “image” outputs are centimeter-scale and larger assemblies. The goal is to print smart materials with the throughput and cost of laser printers, but with the precision and functionality of nanotechnology. If successful, the printer would enable the short-run production of large, engineered, customized microstructures, such as metamaterials with unique responses for secure communications, surveillance and electronic warfare.
Flexible, General Purpose Assembly – Zyvex, SRI, and Harvard
Zyvex aims to create nano-functional micron-scale devices using customizable and scalable manufacturing that is top-down and atomically precise. These high-performance electronic, optical, and nano-mechanical components would be assembled by SRI micro-robots into fully-functional devices and sub-systems such as ultra-sensitive sensors for threat detection, quantum communication devices, and atomic clocks the size of a grain of sand.
SRI’s Levitated Microfactories will seek to combine the precision of MEMS flexures with the versatility and range of pick-and-place robots and the scalability of swarms to assemble and electrically connect micron and millimeter components to build stronger materials, faster electronics, and better sensors.
Many high-impact, minimally invasive surgical techniques are currently performed only by elite surgeons due to the lack of tactile feedback at such small scales relative to what is experienced during conventional surgical procedures. Harvard is developing a new manufacturing paradigm for millimeter-scale surgical tools using low-cost 2D layer-by-layer processes and assembly by folding, resulting in arbitrarily complex meso-scale 3D devices. The goal is for these novel tools to restore the necessary tactile feedback and thereby nurture a new degree of dexterity to perform otherwise demanding micro- and minimally invasive surgeries, and thus expand the availability of life-saving procedures.