CHED 431 |
| Laboratory experiments have been designed to explore aspects of nanoscale chemistry by constructing and spectroscopically analyzing thin films of photonic crystals. One method involves depositing an aqueous suspension of colloidal spheres into a growth cell and allowing the crystal spheres to assemble. Another method produces a film of colloidal spheres embedded in polydimethylsiloxane (PDMS) polymer. This is done by assembling a crystal film and filling in the spaces between the spheres with PDMS. These photonic crystal films exhibit diffraction-based stop bands, which prevent some wavelengths of light from passing through the films. These stop bands can shift reversibly upon exposure of the PDMS-infilled crystal films to some common solvents, visibly changing the color of the crystal. Topics covered in these experiments include crystallization, self-assembly, and diffraction. These experiments are most suited for undergraduate physical or materials chemistry courses, although they are sufficiently simple for use in introductory chemistry classes. |
|
Undergraduate Research Poster Session: Chemical Education
11:00 AM-1:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |