The BF microscopy and FL microscopy images were obtained using a Keyence BZ-8000 microscope (Osaka, Japan). Red fluorescent images were taken using a 540-nm excitation. Results and discussion Figure 4 shows typical UV-visible absorption spectra of the ten-layered LB film of MS and MEK inhibitor C20 with the molar mixing ratio of 1:2 before and after HTT (80°C, 60 min). The well-known J-band, which is located at
594 nm in the as-deposited state, shifts to 599 nm, as shown in Figure 4. The dichroic ratio R ≡ A // / A ⟂ = 1.81 at its peak around 594 nm before HTT but the anisotropy almost disappears (R = 1.03 at 599 nm) after HTT (80°C, 60 min), as shown in Figure 4. Furthermore, the band shape becomes appreciably sharper by HTT. These results are in good agreement with our previous works. Figure 4 Typical absorption spectra of a ten-layered MS-C 20 binary LB film. The thick solid and dashed lines represent A // and A ⟂of the as-deposited state, respectively; the thin solid and dashed lines represent
A // and A ⟂ after hydrothermal treatment (HTT) at 80°C for 60 min. Figure 5a shows a typical FL micrograph of the as-deposited MS-C20 LB film of ten layers with the schematic layered structure shown in Figure 5b. p38 MAPK activity Intense red fluorescence is observed over the whole film area, and the intensity steps are clearly seen at monomolecular steps created by shifts of selleck compound meniscus lines during the deposition process of the MS-C20 LB film, as shown by arrows in Figure 5a. It has been well known that MS and C20 are phase separated in MS-C20 binary LB system. Minari and coworkers estimated that the length of the MS J-aggregate as several hundred nanometers and that the MS J-aggregates are separated from the regions of matrix molecules of C20 based on the analytical model for characterizing the flow orientation effect during the transfer process of the LB deposition . Kato and coworkers also indicated that the MS-C20 mixed system is phase separated
into MS-rich (dye-rich) regions and C20-rich (fatty acid-rich) ones and that the MS-rich (dye-rich) regions are further separated into dye monomer regions and J-aggregate crystallites based on characterization by atomic force microscopy (AFM) observation, FL microscopy, and heptaminol second harmonic generation (SHG) microscopy [9, 28]. Kato and coworkers further estimate that the size of J-aggregate is in the range of 0.5 to 10 μm based on SHG microscopy observation. We hypothesize a similar mesoscopic texture in which the mixed ultrathin film is separated into MS-rich regions and C20-rich ones and the MS-rich regions are further separated into the dye monomer regions and J-aggregate crystallites in the as-deposited MS-C20 mixed system because the dye monomer band and J-band coexist at 545 to 555 nm and 594 nm, respectively, as shown in Figure 4.