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Photoswitchable Spirobenzopyran‐ Based Photochemically Controlled Photonic Crystals
Author(s) -
Kamenjicki Maurer M.,
Lednev I. K.,
Asher S. A.
Publication year - 2005
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200400070
Subject(s) - spiropyran , materials science , diffraction , visible spectrum , colloidal crystal , photonic crystal , self healing hydrogels , photochromism , colloid , photochemistry , chemical engineering , optoelectronics , nanotechnology , optics , polymer chemistry , chemistry , physics , engineering
We have developed a photochemically controlled photonic‐crystal material by covalently attaching spiropyran derivatives to polymerized crystalline colloidal arrays (PCCAs). These PCCAs consist of colloidal particles that self‐assemble into crystalline colloidal arrays (CCAs), which are embedded in crosslinked hydrogels. Photoresponsive PCCAs were made two ways: 1) by functionalizing the hydrogel network with spiropyran derivatives, and 2) by functionalizing the colloidal particles with spiropyran derivatives. These materials can diffract light in the UV, visible, or near‐IR spectral regions. The diffraction of the PCCAs is red‐shifted by exciting the spiropyran with UV light. Alternatively, the diffraction is blue‐shifted by exciting the spiropyran with visible irradiation. Thus, this material acts as a memory storage material where information is recorded by illuminating the PCCA and information is read out by measuring the photonic‐crystal diffraction wavelength. UV excitation forms the open spiropyran form while visible excitation forms the closed spiropyran form. The diffraction shifts result from changes in the free energy of mixing of the PCCA system as the spiropyran is photoexcited to its different stable forms.