Susquehanna Valley Section

April 2005 Meeting

The three hundred fifty-sixth meeting of the Section will be held on Wednesday, April 13, 2005 at the University of Scranton. The guest speaker is Dr. Kalman Koczo of GE Advanced Materials, Tarrytown, NY. He will present a talk entitled "Silicones in Action".

Social: at 5:00 p.m.
Dinner: at 6:00 p.m.
Lecture: at 7:00 p.m.

The social, dinner, and presentation will be in the Trophy Room of the Gunster Memorial Student Center. The evening will begin with a social at 5:00 pm in the Trophy Room of the Gunster Memorial Student Center. The buffet-style dinner will follow at 6:00 p.m. The cost per person is $13.95. Checks should be made out to the University of Scranton, Department of Chemistry and sent to Ms. Debra Jennings, University of Scranton, Department of Chemistry, Scranton, PA 18510 or hand-delivered at the time of the dinner. RSVP to Ms. Debra Jennings at (570) 941-6286.

Directions to the University:
Take I-81 until Exit 185 (Central Scranton expressway). Follow the visitor parking signs to campus. At the first traffic signal, turn right onto Madison Ave, then right onto Linden Street. Parking passes can be made available for those who request them ahead of time. Alternatively, there is street parking that is free after 5:00 p.m. If you would like to park in a lot, call Ms. Debra Jennings to arrange for a parking pass (570) 941-6286.

Directions to the Gunster Student Center:
The Trophy Room is located on the first floor of the Gunster Student Center along the brick commons at the center of campus (see campus map). Directions from Linden Street. Follow Linden Street to the brick commons at the corner of Linden Street and Monroe Avenue. Follow the brick commons up the hill. The Weinberg Memorial Library will be on your left and St. Thomas Hall will be on your right. The second building on your left is the Gunster Student Center (You will see a patio area in front of the building). Enter the first floor of the Gunster Student Center and proceed to the lobby. The Trophy room is the first room on your right.

Silicones in Action
Chemicals derived from silicone oil (polydimethylsiloxane, PDMS) represent products of many applications ranging from food grade antifoams to additives for personal care products, agricultural adjuvants or paints. After a brief survey of the chemistry of PDMS and silicone polyether surfactants, the mechanisms of two interesting colloid phenomena will be discussed which are related to the special surface properties of silicones. Most antifoams (defoamers) contain a blend of PDMS and hydrophobic solid particles (typically silica) and these two components work together to give a spectacular foam breaking efficiency, so that a few ppm of antifoam can control the foaming of a liquid for a long time. The foam channels (so called, Plateau borders) and the so-called "pseudoemulsion film" have a key role in the process. Based on the mechanism, the role of the drop size and the mechanism of antifoam deactivation can be also explained. Among the silicone surfactants the trisiloxanes have a special importance. Silwet L-77, a trisiloxane polyether with eight ethylene oxide groups is also called "superspreader", since its solution can wet hydrophobic surfaces covering huge areas. The phenomenon of superspreading (superwetting) will be demonstrated and its mechanism will be explained with a basic phenomenon of surfactant solutions, the surface tension gradients.

Kalman Koczo has been an R&D scientist at the Silicones division of GE Advanced Materials, in Tarrytown, NY for ten years. He is a native of Hungary and earned his doctorate at the Technical University of Budapest, and started to do research as an assistant professor in the Physical Chemistry Department of this university. His first projects were about the dynamic surface tension of surfactant solutions, the structure and stability of foams and most of his work since then was related to foams and emulsions. He moved with his family to the USA in 1990 and worked for five years as a postdoctoral fellow at the Illinois Institute of Technology where he studied the mechanism of foam-oil interactions, antifoaming action, enhanced oil recovery, and the stability of food foams and emulsions. Since 1995 he worked with silicones at GE. While at GE, he has formulated silicone emulsion and antifoam products and provided technical service on silicone surfactants for coatings. He participated in the investigation of the so-called "superspreading" phenomenon of trisiloxane-ethoxylates which resulted in several presentations and articles.