Making a mini Mona Lisa

Aug 05, 2013
Georgia Tech researchers have created the "Mini Lisa" on a substrate surface approximately 30 microns in width. The image demonstrates a technique that could potentially be used to achieve nano-manufacturing of devices because the team was able to vary the surface concentration of molecules on such short length scales. Credit: Georgia Institute of Technology

The world's most famous painting has now been created on the world's smallest canvas. Researchers at the Georgia Institute of Technology have "painted" the Mona Lisa on a substrate surface approximately 30 microns in width – or one-third the width of a human hair. The team's creation, the "Mini Lisa," demonstrates a technique that could potentially be used to achieve nanomanufacturing of devices because the team was able to vary the surface concentration of molecules on such short-length scales.

The image was created with an and a process called ThermoChemical NanoLithography (TCNL). Going pixel by pixel, the Georgia Tech team positioned a heated cantilever at the substrate surface to create a series of confined nanoscale . By varying only the heat at each location, Ph.D. Candidate Keith Carroll controlled the number of new molecules that were created. The greater the heat, the greater the local concentration. More heat produced the lighter shades of gray, as seen on the Mini Lisa's forehead and hands. Less heat produced the darker shades in her dress and hair seen when the molecular canvas is visualized using fluorescent dye. Each pixel is spaced by 125 .

"By tuning the temperature, our team manipulated chemical reactions to yield variations in the molecular concentrations on the nanoscale," said Jennifer Curtis, an associate professor in the School of Physics and the study's lead author. "The spatial confinement of these reactions provides the precision required to generate complex chemical images like the Mini Lisa."

Making a mini Mona Lisa
This image shows an atomic force microscope (AFM) modified with a thermal cantilever. The AFM scanner allows for precise positioning on the nanoscale while the thermal cantilever induces local nanoscale chemical reactions. Credit: Georgia Institute of Technology

Production of chemical concentration gradients and variations on the sub- scale are difficult to achieve with other techniques, despite a wide range of applications the process could allow. The Georgia Tech TCNL research collaboration, which includes associate professor Elisa Riedo and Regents Professor Seth Marder, produced chemical gradients of amine groups, but expects that the process could be extended for use with other materials.

"We envision TCNL will be capable of patterning gradients of other physical or chemical properties, such as conductivity of graphene," Curtis said. "This technique should enable a wide range of previously inaccessible experiments and applications in fields as diverse as nanoelectronics, optoelectronics and bioengineering."

Another advantage, according to Curtis, is that atomic force microscopes are fairly common and the thermal control is relatively straightforward, making the approach accessible to both academic and industrial laboratories. To facilitate their vision of nano-manufacturing devices with TCNL, the Georgia Tech team has recently integrated nanoarrays of five thermal cantilevers to accelerate the pace of production. Because the technique provides high spatial resolutions at a speed faster than other existing methods, even with a single , Curtis is hopeful that TCNL will provide the option of nanoscale printing integrated with the fabrication of large quantities of surfaces or everyday materials whose dimensions are more than one billion times larger than the TCNL features themselves.

The Mona Lisa, with representation of the temperature that needs to be applied at each position on the surface to get the appropriate final result. The modeling thelps determine what temperatures to use during the TCNL process. Credit: Georgia Institute of Technology

The paper, Fabricating Nanoscale Chemical Gradients with ThermoChemical NanoLithography, is published online by the journal Langmuir.

Explore further: Team reveals molecular structure of water at gold electrodes

More information: pubs.acs.org/doi/abs/10.1021/la400996w

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Moebius
not rated yet Aug 06, 2013
In 1983 the Mona Lisa was probably first converted to a digital image. I know that because I did it, for a Timex Spectrum software development company, pixel by individual pixel.