Energy transfer and excimer formation in layered polymer films prepared by the Langmuir-Blodgett technique

Ito, Shinzaburo; Okubo, Hiromasa; Ohmori, Satoru; Yamamoto, Masahide

doi:10.1016/0040-6090(89)90219-8

Cited by 22 publications

(12 citation statements)

References 6 publications

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“…Previous works showed that the presence of chromophore up to 15% did not affect the stability of the monolayer, which could be transferred onto solid substrates with a good transfer ratio around unity, although a gradual decrease of the collapse pressure was observed with the increase of chromophore content. 14,15 Figure 2 shows the fluorescence spectrum of PVO-PA monolayer at 20 mN m -1 . The P units are selectively excited by 290 nm light through an interference filter with a band width of 10 nm.…”

Section: Resultsmentioning

confidence: 99%

Micro-Brownian Motion of Polymer Segments in a Monolayer at the Air−Water Interface: A Time-Resolved Study of Intralayer Energy Transfer

et al. 1996

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This work is concerned with micro-Brownian motion of polymer segments on a water surface, which is observed as the lateral diffusion of fluorescence probes attached to the polymer chains. Poly(vinyl octanal acetal)s labeled with phenanthrene (P: energy donor) and anthracene (A: energy acceptor) are spread on water, yielding a stable monolayer in which the probes are able to take statistically random distributions in the two-dimensional plane. The time-resolved fluorescence analysis of the energy transfer between the P and A probes allows us to evaluate the acceptor densities and lateral diffusion coefficients of polymer segments on the water surface. The result is obtained by fitting the fluorescence decay data with the theoretical prediction by the Monte Carlo simulation. It is found that this polymer forms a viscous monolayer, in which the lateral diffusion of polymer segments takes place with a diffusion coefficient of ca. 8 × 10-8 cm2 s-1.

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Section: Resultsmentioning

confidence: 99%

Micro-Brownian Motion of Polymer Segments in a Monolayer at the Air−Water Interface: A Time-Resolved Study of Intralayer Energy Transfer

et al. 1996

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“…Figure 4 shows UV absorption spectra of P(VO-VC) LB films before and after irradiation with 289 nm light. The sample consists of 4 layers of precoating PVO, 20 layers of photoreactive P(VO-VC), and 2 layers of protecting PVO on a clean quartz plate in this order. The absorption band of the cinnamoyl group at 280 nm decreases with a few minutes of irradiation.…”

Section: Resultsmentioning

confidence: 99%

Photochemical Stabilization of Ultrathin Polymer Films Prepared by the Langmuir-Blodgett Technique

Hayashi¹,

Mabuchi²,

Mitsuishi³

et al. 1995

Macromolecules

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Photoreactive Langmuir-Blodgett films were made of poly(vinyl octanal acetal-co-vinyl cinnamate) (P(VO-VC)), and the effect of photo-cross-linking on the stability of a layered structure against thermal and chemical treatments has been demonstrated by energy transfer and surface plasmon spectroscopy. Photochemical cross-linking in P(VO-VC) layers easily occurred by UV irradiation for a few minutes, and consequently, the polymer became insoluble in a good solvent, dichloromethane. The durability against the solvent was measured by both UV absorption and surface plasmon resonance.A clear contrast between the irradiated part and nonirradiated part was seen in the picture taken by a surface plasmon microscope. The curing effect on the thermal relaxation of the layered structure was studied by the energy transfer method, which is very sensitive to changes in the layer distances. These findings indicate that photochemical cross-linking of the LB film greatly improves the thermal stability without any serious disordering of the layered structure.

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“…Thus, it is necessary to know the mechanism of the structural relaxation of the LB films. We have studied the layered structure of poly(vinyl octanal acetal) (PVO) LB films and its thermal relaxation behavior through the interlayer energy transfer. − The energy-transfer method is a powerful one to observe the structures in a molecular dimension. Previously, the effect of side chain length 13 and that of molecular weight 14 on the structural relaxation have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…PVO is an excellent LB material because of its good transferability in a wide range of conditions . Besides, it is also useful as a base polymer to which various kinds of fluorescent moieties can be introduced as a side chain . PVOs with various tacticities were prepared and the thermal stability of the LB films was investigated by the energy-transfer method.…”

Section: Introductionmentioning

confidence: 99%

Structural Relaxation of Langmuir−Blodgett Films of Poly(vinyl octanal acetal) with Various Tacticities

et al. 1998

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Poly(vinyl octanal acetal) (PVO) was prepared from poly(vinyl alcohol) (PVA) in which the main chain had three different tacticities and the stereoregularity was characterized by 1H NMR spectroscopy. a-PVO prepared from atactic-PVA and s-PVO from syndiotactic-PVA had similar fractions of cis- and trans-acetals in the main chain, but i-PVO from isotactic-PVA had different ones. Ultrathin films of these polymers were prepared by the Langmuir−Blodgett (LB) technique, and the thermal relaxation of their multilayer structure was investigated by the energy-transfer method. When the LB films were composed of polymers which had a main chain with a similar stereostructure, the polymers were intermingled with each other by the thermal treatment and the onset of the diffusion of polymer segments was affected by the glass-transition temperature of the bulk. In contrast, the polymers with different stereostructures in each layer were not mixed with each other, but phase-separated, presumably forming droplets in the ultrathin films. It is concluded that the relaxation behavior of polymer LB films strongly reflects the stereoregularity of the sample polymers.

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Energy transfer and excimer formation in layered polymer films prepared by the Langmuir-Blodgett technique

Cited by 22 publications

References 6 publications

Micro-Brownian Motion of Polymer Segments in a Monolayer at the Air−Water Interface: A Time-Resolved Study of Intralayer Energy Transfer

Micro-Brownian Motion of Polymer Segments in a Monolayer at the Air−Water Interface: A Time-Resolved Study of Intralayer Energy Transfer

Photochemical Stabilization of Ultrathin Polymer Films Prepared by the Langmuir-Blodgett Technique

Structural Relaxation of Langmuir−Blodgett Films of Poly(vinyl octanal acetal) with Various Tacticities

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