Katharine Burr Blodgett was a long-time collaborator of Dr. Langmuir. She was the first woman to receive a Ph.D. in physics from Cambridge University and the first woman to work in a General Electric laboratory. She was also the first industrial scientist to win the Garvan Medal.
Irving Langmuir described Blodgett as a “gifted experimenter” with a “rare combination of theoretical and practical ability.” She is the author of six U.S. patents relating to thin film deposits. For electrochemists she is best known for the Langmuir-Blodgett technique of monolayer formation.
This technique is very important for many different applications, including electrode modifications. Katharine Burr Blodgett was born on January 10, 1898 in Schenectady, New York. Her parents were George Bedington Blodgett (father) and Katharine Buchanan Burr (mother). She was the second child in the family. Her father had been head of the patent department at the General Electric Company when he died in 1897, shortly before Katharine was born.
After her father’s death, the family moved to New York City, then France, where Blodgett learned to speak, read, and write in French. For her secondary education, in 1912 Blodgett returned to New York City to attend the finest private Rayson School run by three English sisters, where she received a very good education. From a very young age she showed potential in math.
Fortunately, Katie’s mom did not discourage her “unfeminine” interests; instead, she taught Katie to be proud of her abilities. Katharine graduated from high school at the age of fifteen in 1913 and won a scholarship to Bryn Mawr College, a women’s college in Pennsylvania. There, under the tutelage of two inspiring professors ” Charlotte Scott in math and James Barnes in physics ” Blodgett graduated second in her class in 1917 with a degree in physics.
Toward the end of her studies at Bryn Mawr, on a Christmas vacation at age 18, Katharine visited the General Electric Company and met Irving Langmuir, who had worked with her father. Langmuir encouraged her to further her education before trying to obtain a position at the General Electric Company. In 1917, Blodgett entered the University of Chicago and began working with Harvey B. Lemon on the adsorption of gases on charcoal. This knowledge helped her invent gas masks that saved many lives during World War II. She got her masteris degree in chemistry from the University of Chicago in 1918. Her research work was published after the war.
Langmuir was sufficiently impressed with Blodgett’s skill and dedication to hire her immediately as his assistant at General Electric Company. For the first several years they worked on improvements to General Electric Company’s electric lightbulbs. Blodgett was lucky to find work in a place where her father had, in a manner, paved her way. “It was virtually impossible,” she said later, “for women scientists to find professional-level jobs at corporations at that time.”
But because Blodgett was personally known to many General Electric executives, she was allowed to work there. Katharine Burr Blodgett was the first woman to be hired in the General Electric in such a position. No one at General Electric would ever regret this decision.
In 1924, Blodgett won a place as a physics doctoral student at Sir Ernest Rutherford’s Cavendish Laboratory, one of the most prestigious centers of scientific learning in the world. Her doctoral dissertation was about the behavior of electrons in ionized mercury vapor. It is noteworthy that she was the sole author on the publication resulting from her doctoral thesis. Blodgett was the first woman to earn a Ph.D. in physics from Cambridge University in 1926.
Katharine Burr Blodgett (center) demonstrating surface chemistry experiments for visitors at the
opening of General Electric’s new Research Laboratory
In 1926, with Ph.D. in hand, Blodgett returned to the General Electric Company, reestablished her long-time collaboration with Langmuir, and worked with him on many different projects, including those involving thin films. Langmuir, described Blodgett as a “gifted experimenter” with a “rare combination of theoretical and practical ability.” She soon became an expert on thin films in her own right.
In 1938 she invented nonreflecting glass by building up a 44-molecule thick film on the glass surface. Soon after this she developed a gauge to determine the thickness of these thin films. The other methods for measuring this were only accurate to a few thousandths of an inch but Blodgettis way was accurate to about one millionth of an inch.
She obtained six U.S. patents for this work. Because of their many contributions to the science and technology of thin films, that general area is known as Langmuir-Blodgett technology. During the Second World War, Blodgett turned her attention to such military applications as airplane deicing and smokescreen machines.
The invention of the ‘color gauge,’ which permits film measurement within one microinch, began with Dr. Blodgett’s discovery in December 1933 that monomolecular layers of stearic acid, each about one ten-millionth of an inch in thickness, could be successively deposited on to a plate lowered into the solution. This enabled her to construct films in a series of progressive thicknesses, of which each reflects a characteristic color in white light.
Her method of depositing sheets of barium stearate on plates enables a standardized color gauge to be constructed. “Anyone who wishes to measure the thickness of a film which is only a few millionths of an inch thick,” she said, “can compare the color of his film with the series of colors in the gauge. The step on the gauge that matches his film in color will give him a measure of its thickness.”
Dr. Irving Langmuir and Dr. Katherine B. Blodgett with two unidentified coworkers.
The General Electric Company announced in December 1938 that Katherine Blodgett had succeeded in developing a nonreflecting ‘invisible’ glass. Ordinary glass is visible because of the light rays which are reflected from its surface, and when a film is placed upon the glass, Dr. Blodgett discovered that a coating of forty-four layers of one-molecule-thick transparent liquid soap, of about four-millionths of an inch or one-fourth the average wave length of white light, made sheets of glass invisible. Since the reflection from the soap film neutralizes the reflection from the glass itself, the crests and troughs of the two sets of light waves cancel each other, thereby eliminating reflected light. At the same time, the soap varnish is a good conductor of light, permitting 99% of the light striking it to pass through.
The one aspect of Dr. Blodgett’s work on nonreflecting glass requiring further research was the development of harder coatings which could not be wiped off. Some of the applications of the invention are seen in automobile windshields, shop windows, showcases, cameras, spectacles, telescopes, picture frames, and submarine periscopes.
Some important contributions of Katharine Blodgett:
“Films Built by Depositing Successive Monomolecular Layers on a Solid Surface,” Journal of the American Chemical Society 57: 1007 (1935).
First observation that monomolecular layers of soaps could be deposited on metallic surfaces, and that successive layers could be added, layer by layer. Molecular coatings on surfaces is an entire field today; important in physics and applied physics, chemistry, surface science, biology, and medicine.
“Built-Up Films of Barium Stearate and Their Optical Properties,” Physical Review 51: 964 (1937), with I. Langmuir.
Observation that layer by layer deposits of barium-copper stearates could be built up, forming a solid film with a well-defined thickness. This allowed measurement of the optical properties of the films.
“Use of Interference to Extinguish Reflection of Light from Glass,” Physical Review 55: 391 (1939).
Use of interference to extinguish reflections from glass. This utilized her previous experience building films of known thickness, such that reflected rays were greatly diminished by interference. This started the entire field of optical coatings, which are now used universally on eyeglasses, camera lenses, TVs, computer monitors, etc.
Langmuir was the first to show that monolayers can be transferred from the air/water interface to solid substrates for further study. Together with his assistant, Katherine Burr Blodgett, he showed that it was possible to go further and to deposit many monolayers onto the same substrate, thus building up a multilayer stack of any required thickness. Deposited monolayers of whatever thickness are now known as Langmuir-Blodgett films.
Blodgett was honored for her work in many ways – she received honorary doctorates of science from Elmira College in 1939, Brown University in 1942, Western College in1942, and Russell Sage College in 1944. In 1951 she was the first industrial scientist to be awarded the American Chemical Society’s Garvan Medal.
That same year, Schenectady honored her with Katharine Blodgett Day for her scientific and civic contributions. She was elected to be part of the American Physical Society and she was a member of the Optical Society of America. She also won the Photographic Society of America’s Progress Medal in 1972. Unfortunately, she was not included in a history of the General Electric Company that was published in 1953.
Although Katie was an important and very smart scientist, she was not a boring person! Katie had a balanced life. She was an actress with her town’s little theater group. She also volunteered for civic and charitable organizations. She enjoyed writing funny poems such as the one at right.
Katharine Burr Blodgett retired from the General Electric Company in 1963. Blodgett’s discoveries are still important today. Her way of measuring transparent objects is still used today. A native of Schenectady, Dr. Blodgett spent nearly all of her adult life in that city, where she helped pave the way for women physicists and scientists around the world.
Dr. Blodgett passed away in her home at 18 North Church Street, Schenectady, NY at 7:00 am, October 12, 1979, at the age of 81. At her death in 1979, one of her coworkers, Vincent J. Shaefer, recalled that “the methods she developed have become classical tools of the science and technology of surfaces and films. She will be long ” and rightly ” hailed for the simplicity, elegance, and the definitive way in which she presented them to the world.”