Low generation photochromic monodendrons on a solid surface
| Autor: | Vladimir V. Tsukruk, C. Houphouet-Boigny, Alexander Sidorenko, O. Villavicencio, Dominic V. McGrath |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
chemistry.chemical_classification
Azo compound Photoisomerization Metals and Alloys Surfaces and Interfaces Photochemistry Cis trans isomerization Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry.chemical_compound Photochromism chemistry Azobenzene Monolayer Materials Chemistry Organic chemistry Isomerization Alkyl |
| Zdroj: | Thin Solid Films. 410:147-158 |
| ISSN: | 0040-6090 |
| DOI: | 10.1016/s0040-6090(02)00278-x |
| Popis: | Zeroth through third generations of amphiphilic monodendrons containing a benzyl-15-crown-5 polar focal point, photochromic spacer, and alkyl tails as peripheral groups have been investigated for their ability to form photoresponsive surface monolayers. Thickness measurements, scanning probe microscopy, and molecular modeling were used to determine the microstructure of the monolayers. The tilted molecular packing of dendrons in the monolayers is proposed with bulky dendritic shell prohibiting dense packing of azobenzene groups and the aggregate formation. The two-stage trans–cis isomerization was observed for the photochromic monodendron layers composed of various generation dendrons. Fast changes within the first several minutes occurred in the azobenzene-containing monodendrons until the conversion of trans–cis isomerization reaches 13–33%. Then lateral steric hindrances in the monolayer decreases the transformation rate by three orders of magnitude. Diffusion limited intralayer reorganization is suggested to be a limiting factor in the rate of photoisomerization changes. |
| Databáze: | OpenAIRE |
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