Layer by Layer: Katharine Burr Blodgett’s Nearly Invisible Glass

LB trough — Dbroesch (talk), Public domain, via Wikimedia Commons (https://commons.wikimedia.org/wiki/File:LB_trough.jpg)

Sourced history

A Laboratory Visit Opens a Path

Born in Schenectady, New York, in 1898, Katharine Burr Blodgett had a family connection to GE: her father, who died shortly before her birth, had been a patent attorney there. During her senior year at Bryn Mawr College, she toured GE’s laboratories with Irving Langmuir, who had known her father. He encouraged her to continue studying chemistry and physics. After earning a master’s degree at the University of Chicago in 1918, she joined GE as Langmuir’s research assistant, becoming the company’s first woman scientist.

Sources: [1][4]

Sourced history

From Assistant to Research Scientist

Langmuir’s encouragement continued after Blodgett entered the laboratory. In 1924, she went to Cambridge University, where she worked with Ernest Rutherford and prepared a thesis on gaseous electronics. In 1926, she became the first woman to receive a doctorate in physics from Cambridge. Returning to GE as a research scientist, she initially collaborated with Langmuir on improvements to light bulbs. In 1933, they turned again to surface films, moving from the study of single molecular layers toward building and investigating thicker coatings.

Sources: [1][4]

Sourced history

Making the Unseen Measurable

The work required manipulating films too thin to see directly. An account published by Scientific American describes Blodgett using talcum powder as a visual tracer while dipping a metal plate into water carrying a surface film. Moving talc indicated that molecules were transferring onto the plate. Blodgett developed a method for repeatedly transferring films to solid surfaces, building barium stearate coatings up to about 3,000 layers thick. Known as Langmuir-Blodgett films, these coatings gave her a way to control thickness one molecular layer at a time.

Sources: [1][3]

Sourced history

Turning Reflections Against Themselves

Blodgett recognized an application in a familiar nuisance: even clear glass could reflect as much as 10 percent of incoming light. She built a coating with a thickness equal to one-quarter of the average wavelength of visible light. Light reflected from the glass then traveled half a wavelength farther than light reflected from the coating’s surface, allowing most reflections to cancel. She also adjusted the film’s chemical composition to improve the effect. By eliminating almost all reflection, she made the glass nearly invisible.

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Sourced history

Headlines—and a Practical Limitation

GE announced the discovery in December 1938. Blodgett and what the press called “invisible glass” attracted coverage in Time, Life, and The New York Times. Yet the original soap coatings were too soft for commercial products and could readily be wiped away. Other groups subsequently developed tougher coatings and better production methods. Those later advances brought reflection-reducing coatings to products including eyeglasses, camera lenses, microscopes, windshields, televisions, and computer screens. The laboratory achievement and the durable commercial coating were therefore distinct steps in the story.

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Sourced history

A Career Beyond Clear Glass

Blodgett’s research extended well beyond optics. During World War II, she developed poison-gas absorbents, aircraft-wing de-icing methods, and improved smokescreens. She also devised a color gauge for measuring coating thickness and investigated electrically conducting glass. Her honors included four honorary doctorates and the American Chemical Society’s Garvan Medal in 1951. She retired from GE in 1963 and died in 1979. Despite her achievements, a 1953 Science article celebrating 75 years of research at GE laboratories omitted her.

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Commentary

Why Her Story Matters to GE’s Legacy

In our view, Blodgett’s story offers a compelling way to understand GE’s research heritage: not simply as a succession of celebrated products, but as patient work that made new possibilities available. Her career also invites care in assigning credit. Remembering both the scientist behind the discovery and the distinction between a breakthrough and its commercial development makes the legacy more meaningful—and more honest.

Sources

[1] This Month in Physics History | American Physical Society — aps.org
[3] Katharine Burr Blodgett made a breakthrough when she discovered ‘invisible glass’ | Scientific American — Scientific American
[4] Who Invented ‘Invisible’ Glass? | National Inventors Hall of Fame® — invent.org

Written in original words with AI help from the sources above and automatically checked against them. Facts, quotations and commentary are labeled separately; credit belongs to the original authors. GE Heritage Village is independent and not affiliated with GE or Crotonville.