Study on Photochromism of Amphiphilic Spiropyran Monolayers by Surface Reflection.

Shiratori, Koji; Nagamura, Toshihiko

doi:10.2494/photopolymer.14.233

Cited by 3 publications

(4 citation statements)

References 11 publications

(27 reference statements)

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“…Similar phenomena were reported for the Langmuir films of a different merocyanine (spiropyran) derivative. 18 If we assume that there are different types of J-aggregates in the Langmuir and the LB films in terms of excitonic delocalization, the distribution in the Langmuir films should be much larger than that in the LB films.…”

Section: Resultsmentioning

confidence: 99%

“…10-12 J-aggregates in Langmuir and Langmuir-Blodgett (LB) films are of considerable interest because the films have well-defined structures with low-dimensional nature. 4,8,9,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] When chromophores form J-aggregates and the delocalized excitonic state is formed, the absorption band is red-shifted and very narrow with a small Stokes shift compared to the case in which chromophores are in a monomeric state.…”

Section: Introductionmentioning

confidence: 99%

“…J-aggregates of dye molecules have been extensively investigated under various conditions − from the viewpoint of the application to the spectral sensitization, optical storage, , and nonlinear optics. − J-aggregates in Langmuir and Langmuir−Blodgett (LB) films are of considerable interest because the films have well-defined structures with low-dimensional nature. ,,,− When chromophores form J-aggregates and the delocalized excitonic state is formed, the absorption band is red-shifted and very narrow with a small Stokes shift compared to the case in which chromophores are in a monomeric state.…”

Section: Introductionmentioning

confidence: 99%

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Light-Induced J-Aggregation of Merocyanine in Langmuir and Langmuir−Blodgett Films

et al. 2002

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The structures and photoreactions of the Langmuir and LB films of an amphiphilic spiropyran, 1′,3′-dihydro-3′,3′-dimethyl-6-nitro-1′-octadecyl-8-(docosanoyloxymethyl)spiro[2H-1-benzopyran-2,2′-(2H)-indole] (SP) are investigated. A chloroform solution of SP at a concentration of 0.1 mM is spread on the water surface. When the Langmuir film of SP is compressed on a subphase at 30°C and a phase transition takes place, the monolayer changes into a mosaic structure where bilayer domains are buried in the monolayer. When the Langmuir films are illuminated with UV light, SP is isomerized to merocyanine (MC). J-aggregates of MC are formed at high temperatures and at high surface pressures where the bilayer domains are formed. The Langmuir films of SP are transferred as LB films onto solid substrates at 30°C. The LB films consist of the bilayer domains with a diameter of 10 to 20 µm and a height of 4 to 5 nm. Three-dimensional structures are present in almost all the bilayer domains. Room-temperature illumination of the LB films with UV light produces the J-aggregation of MC with the development of dendritic structures starting from the three-dimensional structures in the domains. These dendrites consist of the J-aggregates. Molecules are aligned radially in the dendrites. When the LB film is illuminated at 7°C, the J-aggregation of MC does not proceed. All these results indicate that the criteria of the J-aggregation of MC in the Langmuir and LB films are the presence of the bilayer domains and the nucleation sites with the mobility of the molecules large enough for the morphological change necessary for the J-aggregation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Light-Induced J-Aggregation of Merocyanine in Langmuir and Langmuir−Blodgett Films

et al. 2002

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“…Light-controlled J-aggregation [9][10][11] and triggered J-aggregation [12,13] of dye molecules are more important than J-aggregation itself because modification of the optical properties of selected areas will be possible. However, the design of desirable Pc J-aggregation that could be modulated by light is a real challenge.…”

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confidence: 99%

Novel azobenzene-phthalocyanine dyads――design of photo-modulated J-aggregation

et al. 2009

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Polystyrene bead-based system for optical sensing using spiropyran photoswitches

Scarmagnani¹,

Walsh²,

Slater³

et al. 2008

J. Mater. Chem.

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Spiropyran derivatives have been immobilised on the surface of polystyrene microbeads using different immobilisation strategies. These functionalised polymeric beads can be reversibly switched between the colourless inactive spiropyran (SP) and highly coloured (purple) active merocyanine (MC) forms using low power light sources, such as light emitting diodes (LEDs). A UV-LED (375 nm) is used for the SP to MC conversion, and a white LED (430-760 nm) for the reverse MC to SP conversion. The photochromic behaviour of the coated beads has been characterised using different LEDs and reflection spectroscopy, employing optic fibres and an in-house designed holder. Investigations into the metal-ion binding behaviour of the spiropyran modified microbeads have shown that Cu 2+ ions cause an appreciable colour and spectral change when brought into contact with the beads in the MC form, suggesting that a significant interaction is occurring. However, the Cu 2+ ions can be completely expelled by photonicconversion of the beads into the inactive SP form using a white LED. This sequence has been successfully repeated six times suggesting that it is possible to cycle through activation of the functionalised beads from a non-binding to a binding form (SP to MC) using a UV-LED, allow binding with Cu 2+ ions to occur, and subsequently, expel the bound ions and regenerate the passive SP surface using a white-LED. Other metals, such as calcium, do not cause any appreciable colour or spectral change over the same concentration range and in the presence of the same anion (final concentration 7.1 x 10 -4 M nitrate salt in ethanol). The system is therefore self-indicating in terms of whether the active MC or inactive SP forms are present, and whether Cu 2+ ions are bound to the MC form. In principle, therefore, these functionalised beads could form the basis of a photoswitchable stationary phase for metal ion binding and detection: irradiation of the stationary phase with UV-LEDs causes retention of guest species due to the presence of the MC form, while subsequent exposure to white LEDs causes release of guest species into the mobile phase.

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Study on Photochromism of Amphiphilic Spiropyran Monolayers by Surface Reflection.

Cited by 3 publications

References 11 publications

Light-Induced J-Aggregation of Merocyanine in Langmuir and Langmuir−Blodgett Films

Light-Induced J-Aggregation of Merocyanine in Langmuir and Langmuir−Blodgett Films

Novel azobenzene-phthalocyanine dyads――design of photo-modulated J-aggregation

Polystyrene bead-based system for optical sensing using spiropyran photoswitches

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