Engineers from Texas A&M University and Virginia Tech report important new insights into nanoporous gold--a material with growing applications in several areas, including energy storage and biomedical devices--all without stepping into a lab.
Instead of conducting any additional experiments, the team used image-analysis software developed in-house to "mine" the existing literature on nanoporous gold (NPG). Specifically, the software analyzed photographs of NPG from some 150 peer-reviewed papers, quickly measuring key features of the material that the researchers then correlated with written descriptions of how the samples were prepared. One of the results? A recipe, of sorts, for how to make NPG with specific characteristics.
"We were able to back out a quantitative law that explains how you can change NPG features by changing the processing times and temperatures," said Ian McCue, a postdoctoral researcher in the Texas A&M Department of Materials Science and Engineering. McCue is lead author of a paper on the work published online in the April 30 issue of Scientific Reports.
"Before our work, engineers knew of one tunable 'knob' for NPG. Now we have a second one that could give us even more control over the material's properties," said Josh Stuckner, a graduate student at Virginia Tech and co-author of the paper. Stuckner developed the software that allowed the new insights.
The material is a three-dimensional porous network of interweaving strands, or ligaments. Multiple ligaments, in turn, connect at points called nodes. All of these features are almost unimaginably small. Stuckner notes, for example, that some of the smaller pores would fit about three strands of DNA side by side. As a result, McCue said the overall structure is very complex and it's been extremely difficult and time-consuming to measure features like the lengths between nodes and the diameters of ligaments. But Stuckner's software has changed that.
"Manually it might take 20 minutes to over an hour to measure the features associated with one image," Stuckner said. "We can do it in a minute, or even just tell the computer to measure a whole slew of images while we walk away."
"We had to throw out a lot of data due to poor image quality or a lack of written information on how a given NPG was processed," McCue said. "The new guidelines could prevent that, ultimately allowing better data mining not only for NPG but for other materials."