Cadet Physics Project Measures Results in Nanometers
Institute Report, March 2012
“It’s kind of nice to be on the leading edge.”
That’s precisely where physics major Alex Firehammer is completing his capstone project in VMI’s thin films lab.
Firehammer’s project is to optimize the deposition process for optical filters on the lab’s new automatic stainer, one of several devices purchased in the last five years with the assistance of the Jackson-Hope and Mallory Hall renovation funds.
In other words, Firehammer is working to identify the best automated process for creating thin films. Thin films are created in the VMI lab by dipping a microscope slide into a solution over and over again, each time adding layers.
Holding up a translucent orange microscope slide, Firehammer said, “I have about 50 layers on each side, about 150 nanometers.” A nanometer is a billionth of a meter, explained Firehammer’s faculty mentor Lt. Col. Daniela Topasna.
Firehammer is dipping the films both by hand and by machine to test the automatic stainer’s efficiency.
“With the machine we can dip 30 slides at any one time,” said Firehammer. “By hand, even five or six gets pretty hectic.”
Firehammer’s interest in thin films originated in reports he did in his Modern Physics class. He came across a project using them to make solar panels; nanotechnology can make solar panels lighter, cheaper, and more efficient. At VMI’s thin films lab, projects are under way using nanotechnology to make colored glass that absorbs certain wavelengths of light while allowing others through, creating optical filters that can be used in instruments. The same kind of technology can be used to make protective goggles.
Firehammer’s project builds thin films using a process based on electrostatic attraction, said Topasna, one of only two or three methods that allow control at the nanometer level. It’s a method being investigated in a number of research projects all over the world – at Virginia Tech and the Massachusetts Institute of Technology, in Germany and in Australia.
In the electrostatic self-assembly method, the slides are dipped in positive and negative solutions alternately, and the layers attract each other like magnets.
“The nice thing about the method is it’s based on a water solution; you don’t have to use nasty solvents,” said Topasna. “It’s very environmentally friendly.”
Topasna said nanotechnology allows the creation of films coating any size or shape; the substrate, or form to be coated, can be anything, from polyester to metal to glass to polymers. And the films can be functionalized based on the materials used: polymers, nanoparticles, proteins, and DNA are among the possibilities.
“The tendency now is to make smaller devices. This is one of the methods to do that,” said Topasna. “As things get smaller, you run into the problem of quantum effects. Silicon technology is limited – traditional methods are reaching their limit.”
Two other thin film projects are also in progress at VMI. One is creating photovoltaic films, which convert solar energy into electric energy, as in solar panels. The other uses titania particles to create antireflective coatings, such as to evade radar transmissions.
Firehammer’s thin films project is his second physics research project. Two summers ago, Firehammer’s Summer Undergraduate Research Institute (SURI) project created a carbon dioxide laser.
“I thought it was the coolest thing I had ever done,” said Firehammer.
All this lab work has opened up the world of physics for Firehammer, who is one of only four physics majors graduating this May.
“It’s a whole world of awful math,” said Firehammer, reflecting on the five cadets in his class who switched from physics to other majors. “Of course you get past it. You stick with it, and you’re proud after you finish it.”
And the lab work has resulted in advanced training for Firehammer, both in the processes themselves – how to tell when something isn’t working properly, for instance – and in how to use instruments that are so specialized their use is never taught in the classroom. In addition to trying out that automatic stainer, Firehammer has used the lab’s scanning electron microsope, which magnifies 10,000 times, and its spectro photometer to assess the films he creates.
“Since Alex has started work on the project, he has demonstrated a good work ethic, initiative, and has been very efficient since the first tasks that were given to him. He is organized in the lab and does his best to apply the methods correctly,” said Topasna, who has encouraged Firehammer to help identify and train a cadet to work in the lab next year. Firehammer will commission into the U.S. Navy in May and has been selected to be a pilot.
The cost of all those slides and solutions, and other supplies such as beakers, adds up. Firehammer received a grant this semester from the Wetmore Fund to help cover these costs. He was encouraged to apply by Topasna, who finds these grants helpful whenever she works with a cadet on an undergraduate research project.
Administered by the VMI Center for Undergraduate Research, the Wetmore Fund offers maximum grants of $300 for supplies for undergraduate research during the academic year.