Multifarious Photoinduced Morphologies in Monomolecular Films of Azobenzene Side Chain Polymer on Mica

Autor:	Jun-ya Kojima, Kunihiro Ichimura, Takahiro Seki
Rok vydání:	2000
Předmět:	Vinyl alcohol Azo compound Polymers and Plastics Photoisomerization Organic Chemistry Photochemistry Cis trans isomerization Inorganic Chemistry chemistry.chemical_compound chemistry Azobenzene Monolayer Materials Chemistry Side chain Mica
Zdroj:	Macromolecules. 33:2709-2717
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma991439i
Popis:	Monomolecular films of a poly(vinyl alcohol) derivative having an azobenzene (Az) side chain (6Az10-PVA) transferred onto mica by the Langmuir−Blodgett technique were observed by atomic force microscopy in the noncontact mode. Multifarious features of the film morphology after the thermal and photostimulated processes were revealed, which were strongly dependent on the humidity of the atmosphere, the lateral packing density of the monolayer, and the light exposure dose. In a humidified atmosphere, a low-density film (1.2 nm2 Az-1) showed a network morphologythat exhibited a two-dimensional expansion upon irradiation with UV (365 nm) light (trans → cis Az isomerization). The films having the higher densities (0.4 or 0.3 nm2 Az-1) gave spongy-shaped or partially collapsed films and indicated a formation of three-dimensional protrusions on UV light illumination. In comparison with the spectroscopic data, these morphological changes could be related with the proceeding of the Az photoreaction. The morphologic...
Databáze:	OpenAIRE
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