title: Triggered J-aggregation in mixed Langmuir-Blodgett films of amphiphilic spiropyran having a methoxy group at the 5' position and an azobenzene derivative.
abstract: Here, we describe the formation of J-aggregates triggered by isomerization of an azobenzene derivative, N-[p-[(p-dodecylphenylazo)phenyloxy]dodecylpyridinium bromide (AzP), in mixed Langmuir-Blodgett (LB) films that contain an amphiphilic spiropyran with a methoxy group at the 5' position, MeO-SP1822. Pure LB films of MeO-SP1822 consist of multilayer domains embedded in a monolayer. UV irradiation of the films causes the isomerization of MeO-SP1822 to its merocyanine form, MeO-MC1822. Pure LB films of AzP comprise finger-like domains and granular domains. Irradiating mixed films of MeO-SP1822 and AzP with alternating UV and visible light causes J-aggregation of MeO-MC1822, with the amount of J-aggregates reaching a maximum at a 1:1 molar ratio. J-aggregation occurs in flat finger-like structures originating in the AzP-rich granular domains that are located on top of the MeO-MC1822-rich multilayer domains. J-aggregates are also present under the AzP-rich granular domains, though these domains do not serve as nucleation sites for the finger-like structures. We propose that granular domains serving as nucleation sites are partially buried in the multilayer domains, whereas those triggering the J-aggregation of MeO-MC1822 under the granular domains are situated on top of the multilayer domains.
authors.affiliation: Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Shinnosuke
authors.initials: S
authors.lastname: Tozawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Matani
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Hayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Shibata
authors.forename: Mutsuyoshi
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry; D007211:Indoles / Q000737:chemistry; D007536:Isomerism; D008567:Membranes, Artificial; D015394:Molecular Structure; D009574:Nitro Compounds / Q000737:chemistry; D011726:Pyridinium Compounds / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents; D014466:Ultraviolet Rays
chemical_list: D001391:Azo Compounds; D001578:Benzopyrans; D007211:Indoles; D008567:Membranes, Artificial; D009574:Nitro Compounds; D011726:Pyridinium Compounds; D013501:Surface-Active Agents; C088184:spiropyran; C009850:azobenzene