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Allyson Ho, William P . Clements High School, Sugar Land, TX Alex Thachara, The Wheatley School, Old Westbury, NY

National Winners $20,000 Team Scholarship

Southwest Region Silver Medal Winners

"The Effects of Nanoparticles on Selective Gas Permeability of Thin Film Membranes Using Supercritical Fluid"

In their research, Allyson Ho and Alex Thachara explored ways to improve, modify and control the porosity of polymer thin films. The applications for this technology are many: gas masks which filter out large molecules, viruses and bacteria while allowing free flow of oxygen and carbon dioxide, specialized food wrappings, as well as specialized permeable bandages for burns. Such devices could for instance prevent airborne pathogens such as SARS from infecting people and provide preventative measures against bio-terrorism.


Ms. Ho and Mr. Thachara combined two techniques to modify the permeability of very thin polymer films made from polystyrene and poly (methyl methacrylate). They added assorted nanoparticles, then subjected the films to treatment in high pressure, super-critical carbon dioxide – pressure greater than 1,073 pounds per square inch and at temperatures greater than 31.3 celsius. Both these treatments affect the porosity. Ms Ho and Mr. Thachara carefully controlled and measured the resulting oxygen permeability of their films after a combination of these treatments. Their mentors were Luckner John Jerome and Dr. Miriam Rafailovich.

Fluent in Mandarin, Ms. Ho, a junior, enjoys swimming and arts and crafts. She is a member of the Junior Engineering Technical Society (JETS), Youth Expanding Service (YES) and Texas Association of Future Educators (TAFE). She received semi-finalist honors in the 2003 Siemens Westinghouse Competition and honorable mention at the 2004 Exxon Mobile Texas Science and Engineering Fair. Ms. Ho’s sister, Madelyn, was a national finalist in the 2002-03 Siemens Westinghouse Competition.

Fluent in Malayalam and Spanish, Mr. Thachara, a junior, has been playing the clarinet for almost ten years. He is a member of the Medical Explorers Club and volunteers at North Shore University Hospital. He enjoys basketball and football and plans to study pre-law in college.

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