News Release

Lessons in chemistry and gallantry offered in the same lecture

Peer-Reviewed Publication

Virginia Tech

Blacksburg, Va., August 20, 2000 -- The history of surface chemistry is a story of honorable men and pioneering women.

Virginia Tech Distinguished Professor of Chemistry James Wightman will tell the story with verve and passion during the American Chemical Society 220th national meeting in Washington, D.C. Aug. 20-24.

Even if you know the story, it's a treat to hear Wightman tell the tale of Benjamin Franklin -- observant enough to notice smooth wakes behind ships at sea, curious enough to quiz a captain and learn about cooks who throw greasy slop overboard, well-read enough to recall Pliny's ancient writings about oil calming waters (AD 23-79), and energetic enough to conduct his own experiments by dropping teaspoons of oil on ponds in England and America. Wightman, who resembles the statesman/scientist, especially in early American garb, treks annually to Virginia Tech's duck pond with students in tow to recreate Franklin's demonstration.

In his ACS presentation Sunday, Aug. 20, Wightman will continue the history lesson in honor of Charles H. Giles, late professor of chemistry at the University of Strathclyde. Wightman will use Giles' carefully researched notes to explain that while Franklin observed effect, about a century later, a German hausfrau named Agnes Pockels was the first to determine cause and to measure the monolayer. We know of her work thanks to a gallant knight.

Pockels did not attend college because when she first considered it in the mid 1800s; women were not admitted. Not much later, when women were being accepted, Pockels' aging parents asked her not to. So, unmarried and devoting her life to the care of her invalid parents, although not-yet 20 years old, she occupied her mind by reading material provided by her brother, Fritz, who was a student at the University of Heidelburg. And she conducted experiments in the kitchen sink. Using kitchen bowls, string, and buttons, she developed the first surface film balance.

Because of her lack of credentials, she had no outlet to publish her results. So, having read Lord Rayleigh's work on properties of water surfaces, she shared her results with him. Rayleigh (John William Strutt, Third Baron Rayleigh) had been knighted for his contributions to science, but, upon receiving Pockels' letter, he proved himself worthy of his title in every respect. He sent the work to Nature magazine on March 2, with the following note: "I shall be obliged if you can find space for the accompanying translation of an interesting letter which I have received from a German lady, who with very homely appliances has arrived at valuable results respecting the behaviour of contaminated water surfaces. The earlier part of Miss Pockel's letter covers nearly the same ground as some of my own recent work, and in the main harmonizes with it. The later sections seem to me very suggestive, raising, if they do not fully answer, many important questions. I hope soon to find opportunity for repeating some of Miss Pockels' experiments."

Nature published the work on March 12, 1891. The physics department at the University of Heidelburg subsequently invited Pockels to work in their lab, which she did for 40 years.

Wightman's retelling of Giles' history will then flash forward three decades and bring surface chemistry research back to America with Irving Langmuir, an industrial research scientist with General Electric, who studied the work of Rayleigh and Pockels, among others, and learned lessons not only in surface chemistry but in fair play. Langmuir discovered that molecules in a monolayer on a surface will assume a common orientation. In a single layer of molecules on water, for instance, hydrophobic ends will be away from the water and hydrophilic ends will be toward the water.

Langmuir received the Nobel Prize in Chemistry in 1932 for his discovery. When the Nobel committee had a film made of the laureate in his lab, he gave half of his presentation time to his assistant, Katherine Blodgett. Their joint research had demonstrated that the preferential orientation of monolayers could be used to stack monolayers of selected molecules to whatever thickness desired, a product now known as Langmuir-Blodgett films.

The paper Wightman dedicated to Giles, "Agnes Pockels: Forerunner of Langmuir-Blodgett monolayers (CHED 23)," will be delivered at 3:35 p.m. Sunday in the Renaissance Hotel, Washington Room 3 as part of the symposium on "Historically Important Chemical Educators."

###

PR Contact: Susan Trulove
540-231-5646 strulove@vt.edu



Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.