NIST Looks at Big Picture of Nanoparticle Manufacturing

A recent paper in the journal ACS Applied Nano Materials prepared by the National Institute of Standards and Technology (NIST)—Nanoparticle Manufacturing—Heterogeneity Through Processes to Products—is the culmination of a study initiated by a workshop organized by NIST that focused on the fundamental challenge of reducing or mitigating heterogeneity, the inadvertent variations in nanoparticle size, shape and other characteristics that occur during their manufacturing.

The authors point out that today’s engineered nanoparticles are integral components in everything from the quantum dot nanocrystals coloring the brilliant displays of state-of-the-art televisions and nanocomposites, to the miniscule bits of silver helping bandages protect against infection. However, commercial ventures that look to profit from these tiny building blocks face quality control issues that, if not addressed, can reduce efficiency, increase production costs and limit commercial impact of the products that incorporate them.

With the aim of helping to overcome these obstacles, the NIST and the nonprofit World Technology Evaluation Center (WTEC) advocate that nanoparticle researchers, manufacturers and administrators “connect the dots” by considering their shared challenges broadly and tackling them collectively rather than individually. This includes transferring knowledge across disciplines, coordinating actions between organizations and sharing resources to facilitate solutions.

The new paper’s researchers from NIST’s Center of Nanoscale Science and Technology and Materials Science and Engineering Division, according to lead author NIST physical scientist Samuel Stavis, “looked at the big picture of nanoparticle manufacturing to identify problems that are common for different materials, processes and applications….Solving these problems could advance the entire enterprise.”

Jeffery Fagan, NIST chemical engineer and co-author notes that heterogeneity can translate to significant consequences in nanoparticle manufacturing. As such, the paper stresses that the most profitable innovations in nanoparticle manufacturing minimize heterogeneity during the early stages of the operation, reducing the need for subsequent processing. This decreases waste, simplifies characterization and improves the integration of nanoparticles into products—all of which save money.

The paper’s authors illustrate this point by comparing the production of gold nanoparticles and carbon nanotubes. For gold, the initial synthesis costs can be high, but the similarity of the nanoparticles produced requires less purification and characterization. Therefore, they can be made into a variety of products, such as sensors, at relatively low costs, they note.  In contrast, the more heterogeneous carbon nanotubes are less expensive to synthesize but require more processing to yield those with desired properties. The added costs during manufacturing currently make nanotubes practical only for high-value applications such as digital logic devices.

“Although these nanoparticles and their end products are very different, the stakeholders in their manufacture can learn much from each other’s best practices…by sharing knowledge, they might be able to improve both seemingly disparate operations,” says J. Alexander Liddle, NIST materials scientist and co-author. Finding ways like this to connect the dots is critically important for new ventures seeking to transfer nanoparticle technologies from laboratory to market, according to the authors.

WTEC nanotechnology consultant and co-author Michael Stopa notes that nanoparticle manufacturing can become so costly that funding runs out before a product can be brought to market. “In our paper, we outline several opportunities for improving the odds that new ventures will survive their journeys through this technology transfer ‘valley of death.’”

In the paper, the authors discuss how manufacturing challenges and innovations are affecting the ever-growing number of applications for nanoparticles, including those in the areas of electronics, energy, health care and materials.