Photochemical phase transition

Spectral change of polyion complex films due to thermal and photochemical phase transition. 

Photochemical Phase Transitions in Cuest/Host Systems... 

Photochemically induced phase transition photochemical phase transition) of LCs in guest/host systems is interpreted as follows. 81 If a small population of photochromic compounds such as azobenzene are dispersed in nematic LCs (NLCs), the phase structure of the NLCs is susceptible to change induced by photochemical reac-... 

Photochemical phase transition response time has been investigated in detail. 

As described above, the temperature range in which to induce photochemical phase transition of NLCs in guest/host systems is limited. In the temperature ranges above the Tni of trons-azobenzene/NLC mixtures and below the Tni of cis-azoben-... 

Fig. 8 Ti me-resolved measurements of the photochemical phase transition of the polymer azobenzene liquid crystal.

Shishido A, Tsutsumi O, Kanazawa A, Shiono T, Ikeda T, Tamai N. (1997) Distinct photochemical phase transition behavior of azobenzene liquid crystals evaluated by reflection-mode analysis. J Phys Chem B 101 2806-2810... 

Tong X, Cui L, Zhao Y. (2004) Confinement effects on photoahgnment, photochemical phase transition and thermochromic behavior of liquid crystahine azobenzene-containing diblock copolymers. Macromolecules 37 3101-3112... 

K.inazawa, A., Hirano, S., Shushido, A., Hasegawa, M., Tsutsumi, O., Shiono, T., Ikeda, T., Nagase, Y., Akiyama, E., and Takamura, Y. Photochemical phase transition behavior of polymer azobenzene liquid crystals with flexible siloxane units as a side-chain spacer. Liquid Crystals 23,193 1997). 

Yamamoto, X, Hasegawa, M., Kanazawa, A., Shiono, T., and Ikeda, T. Holographic gratings and holographic image storage via photochemical phase transitions of polymer azobenzene liquid-crystal films./. Materials Chem. 2000, 10, pp. 337-342. 

T. Ikeda, T. Miyamoto, S. Kurihara, M. Tsukada, and S. Tazuke, Effect of structure of photoresponsive molecules on photochemical phase transition of liquid crystals. II. Photochemical phase transition behavior of photochromic guest/host mixtures Mol. Cryst. Liq. Cryst. 182, 373-385 (1990). 

T. Ikeda, T. Sasaki, and H.-B. Kim, Intrinsic response of polymer liquid crystals in photochemical phase transition, 7. Phys. Chem. 95, 509-511 (1991). 

T. Sasaki, T. Ikeda, and K. Ichimura, Time-resolved observation of photochemical phase transition in polymer liquid crystal, Macromolecules 25, 3807-3811 (1992). 

Yamamoto T, et al. 2001. Phase type gratings formed by photochemical phase transition of polymer azobenzene liquid crystal. 2. Rapid switching of diffraction beams in thin films. J Phys Chem B 105(12) 2308 2313. 

Photochemical Phase Transitions of LCs. Cooperative motion of molecules in LC phases may be most advantageous in changing the molecular alignment by external stimuli. If a small portion of LC molecules change their... 

The photochemically induced phase transitions ( photochemical phase transitions ) are interpreted in terms of a change in the phase transition temperature of LC systems upon accumulation of one isomer of the photochromic guest molecule (Sung et al., 2002 Legge and Mitchell, 1992). The trans form of the... 

Figure 3.18. (a) Photoisomerization of 4,4 -disubstituted azobenzene derivative and (b, c) phase diagrams of the photochemical phase transition of azobenzene/ LC systems (N, nematic I, isotropic). Source Ikeda, 2003. 

LC copolymers were prepared, and their photochemical phase transition behavior was examined (Tsutsumi et al., 1998a Sasaki et al., 1992 Ikeda et al., 1990b,c). One of the important factors of the photoresponsive LCs is their responses to optical stimuli. In this respect, the response time of the photochemical phase transition has been explored by time-resolved measurements (Sasaki et al., 1992 Ikeda et al., 1991 Kurihara et al., 1990). 

Yamamoto T, Hasegawa M, Kanazawa A, Shiono T, Ikeda T. 1999. Phase t q)e gratings formed by photochemical phase transition of pol5mer azobenzene liquid crystals enhancement of diffraction efficiency by spatial modulation of molecular alignment. J Phys Chem 103 9873 9878. 

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