MIT’s Mildred Dresselhaus helped build the foundation for nanoscience and along the way mentored young women scientists.
Neil Savage
With her silver hair, warm smile, and unassuming black sweater—worn even on a hot July day—Mildred Dresselhaus might be mistaken by someone outside the world of physics as an average grandmother. Indeed, at 75, she is a mother and a grandmother. She’s also a world expert in the physics of carbon, a leading advocate for women in science, a former Department of Energy science director during the second Clinton administration, and one of only 13 people who hold the prestigious title of Institute Professor at MIT.
As an Institute Professor, she’s free of teaching and other departmental obligations and continues to work full time on her research on carbon nanotubes. These molecules are strong, stable, hollow cylinders made of carbon atoms linked together. Just a few nanometers in diameter and a few millimeters long, carbon nanotubes may have useful properties for a wide range of applications, from electronics to construction. Dresselhaus came up with a way to use spectroscopy to study the electrical behavior of these nanotubes, a critical step in understanding how to use them.
“She was one of the first, if not the first, to be able to do experiments on individual carbon nanotubes,” says Peter Eklund, a physics professor in the Nanomaterials Physics Research Group at Pennsylvania State University.
Dresselhaus’s career has been about improving the theoretical understanding of materials. In the 1960s, she began her studies on carbon by setting out to describe the electronic structure of graphite, which was not understood at the time. One of her early experiments showed that what researchers had thought were negatively charged electrons actually turned out to be positively charged “holes,” a critical distinction in figuring out how the material behaved.
Later on, scientists at Bell Laboratories, recognizing Dresselhaus for her graphite expertise, got in touch with her after they discovered that adding alkali metals to graphite created a superconducting material, capable of transmitting electricity with almost no resistance. They sought her help in figuring out how this worked. Eventually, Dresselhaus developed a method to measure the properties of the material so that researchers could find the optimum amount of alkalis to add. That helped advance the understanding of superconductors, a field of research in which a lot about the behavior of the materials remains unknown.
More recently, Dresselhaus has been applying her expertise to alternative energy. In 2003, as President Bush proposed new research to create a fleet of hydrogen-powered automobiles, the Department of Energy (DOE) asked Dresselhaus, who had been director of the DOE’s Office of Science during President Clinton’s last year in office, to head a study of what research needed to be done to build a hydrogen economy.
She’s led several scientific societies and received plenty of recognition and awards, including the Heinz Foundation’s Award for Technology, the Economy, and Employment last year, which came with a $250,000 prize. The award recognized not only her scientific contributions but also her role promoting the participation of women in science.
When she arrived at MIT in 1967, only four percent of students were women (it’s now more than 40 percent), and the idea of a female president was unheard of. It wasn’t too long before Dresselhaus started acting as a mentor to female students. “It was sort of maternal instinct,” she says. “So many of these young women used to come here with these ‘How do I make it?’ issues that I started working with them.”
The idea of helping younger women came naturally. Growing up in the Bronx in the 1940s, young Mildred Spiewak had few educational options. The Bronx High School of Science was closed to girls, so she went to Hunter College High School, then on to Hunter College, which educated female students to become teachers. In college, she met Rosalyn Yalow, who was teaching physics at the time because she couldn’t get a job as a research physicist. Yalow, who became a lifelong friend, encouraged her to follow her scientific interests. Dresselhaus did her graduate studies at Cambridge, Harvard, and finally the University of Chicago. Yalow, meanwhile, got a job as a medical physicist at the Bronx Veterans Administration Hospital and created radioimmunoassays to measure hormones in the body. Yalow won the Nobel Prize in 1977 for her work.
Dresselhaus says the experience of young women in the sciences today is completely different. Even the comments last year from then-Harvard president Lawrence Summers questioning whether women were capable of doing science didn’t bother her that much. “It was too off-the-wall,” she says, adding that if anything, Summers’s comments helped women by illustrating that bias against women in science still needs to be overcome.
Dresselhaus says she never set out to be an advocate; it’s just a role that was thrust upon her. “I’m a woman in science. I can’t help that. I just got put in this position.”