Thermally Switchable Periodicities and Diffraction from Novel Mesoscopically Ordered Materials.
Abstract
Two novel switchable, mesoscopically periodic materials were created by combining crystalline colloidal array (CCA) self-assembly with the temperature-induced volume phase transition of poly(N-isopropylacrylamide) (PNIPAM). Body-centered cubic (BCC) CCA of hydrated, swollen PNIPAM particles Bragg diffract infrared (IR), visible, and ultraviolet (UV) light weakly, while arrays of compact shrunken particles diffract efficiently. A tunable diffracting array was also created by embedding a CCA of polystyrene spheres within a PNIPAM hydrogel, that swells and contracts with temperature; thus, the array lattice constant varies with temperature and the diffracted wavelength is thermally tunable across the entire visible spectrum. These materials may find applications in many areas of optics and materials science.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1996
- Accession Number
- ADA314858
Entities
People
- A. S. Tse
- H. B. Sunkara
- J. M. Weissman
- S. A. Asher
Organizations
- University of Pittsburgh