Researchers Develop Rapid Assembly Process in Nanoscale

The rapidly advancing field of nanotechnology demands simple and quick fabrication processes in the nanoscale. With more lightweight flexible plastic solar collectors (organic photovoltaics) and flexible plastic electronics, the challenge is to develop fast, large scale and cost-effective nanoscale assembly processes of different polymers to make flexible devices and materials.

Previous nanoscale polymer assembly methods used specially synthesized polymers that were not available commercially and required annealing, a process that can take up to 48 hours.

Research conducted at the National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-rate Nanomanufacturing (CHN) by the University of Massachusetts Lowell and Northeastern University led to the development of rapid template-assisted assembly of polymer blends in the nanoscale. The research team created a highly effective process that takes only 30 seconds to complete and does not require annealing.

This study, funded by the NSF, is published online in the journal Advanced Materials.

“The techniques demonstrated in this work can be used in high-rate nanomanufacturing of polymer-based products, from flexible electronics to materials for medical applications,” said Joey Mead, Ph.D., co-author of this paper and deputy director of UMass Lowell’s CHN. “This is why we say nanomanufacturing is an ‘enabling technology’ — it impacts many fields and could create entirely new economic sectors.”

The short assembly times make it possible to fabricate binary-component polymer arrays at high rates, a critical component for commercially relevant and cost effective nanomanufacturing. The research team used nanotemplates to direct the assembly of each single polymer component in a specific location. Most importantly, the team selectively assembled polymer blends to desired sites through a one-step process with high specificity and selectivity.

This novel and versatile approach to creating nanoscale polymeric patterns can be used to generate a variety of complex geometries, including 90-degree bends, T-junctions and square and circle arrays. In addition, these patterns can be made over a large area with high resolution, overcoming the constraint of limited areas and slow rates.

“This approach for preparation of chemically functionalized substrates has the potential for a wide variety of applications, including biosensors, biochips, photonics, nanolithography and electronics,” said Ahmed Busnaina, Ph.D., co-author of this paper and director of Northeastern’s CHN.

The research was led by professors Joey Mead, Ph.D., Carol Barry, D.Eng., Ming Wei, D.Eng., Jun Lee, D.Eng., and Liang Fang from the University of Massachusetts Lowell and Ahmed Busnaina, Ph.D., Sivasubramanian Somu, Ph.D. and Xugang Xiong from Northeastern.

About the NSF Nanoscale Science and Engineering Center for High-rate Nanomanufacturing

In the fall of 2004, the National Science Foundation awarded Northeastern University and its partners, the University of Massachusetts Lowell, the University of New Hampshire, Michigan State University and the Museum of Science, a Nanoscale Science and Engineering Center for high-rate Nanomanufacturing with funding of $12.4 million over five years. The Center for high-rate nanomanufacturing is focused on developing tools and processes that will enable high-rate/high-volume bottom-up, precise, parallel assembly of nanoelements (such as carbon nanotubes, nanoparticles, etc.) and polymer nanostructures. The center nanotemplates are utilized to conduct fast massive directed assembly of nanoscale elements by controlling the forces required to assemble, detach, and transfer nanoelements at high rates and over large areas. The developed nanotemplates and tools will accelerate the creation of highly anticipated commercial products and will enable the creation of an entirely new generation of applications.