Chemistry Reference
In-Depth Information
Figure 8. Polar diagrams of absorbances measured from LC cells fabricated with 6F-HAB-CI films
which were treated by 0
°
(
θ
)- and 90
°
(
θ
)-exposure protocols in Table 1: here,
θ
is defined as the an-
gle between the longer axis of the glass slide and the electric vector of the linearly polarized actinic
UV light (260-380 nm wavelength). An energy of 0.50 J/cm
2
per exposure was employed.
sequential exposures because of large consumption of unreacted cinnamoyl moie-
ties. However, the polar diagrams obtained for the CI-0.25#5, CI-0.25#6, CI-
0.25#7 and CI-0.25#8 cells indicate that the photoalignment of polymer chains
generated by the first UV-exposure still governs strongly the LC alignment even
on the film sequentially exposured more than two times.
The sequential 0
)-exposures were conducted further with a high
exposure dose of 0.50-1.50 J/cm
2
. Figure 8 shows the polar diagrams measured
for the LC cells fabricated with polymer films exposed sequentially to a polarized
UV light of 0.50 J/cm
2
exposure dose. The first 0
°
(
θ
)- and 90
°
(
θ
°
(
θ
)-exposure causes the LC
alignment along the direction of
)-
exposure, the LC alignment is disturbed to some extent, but the principal director
of the LC alignment apparently is not changed. The slight disturbance in the LC
alignment is healed completely by the subsequent 0
ϕ
= 100
°
= 280
°
. For the subsequent 90
°
(
θ
°
(
θ
)-exposure. Thereafter, the
LC alignment apparently is not sensitive to further 90
)-exposure.
Figure 9 presents the polar diagrams for the LC cells prepared with polymer
films subjected to a linearly polarized UV light with an exposure dose of 1.50
J/cm
2
by sequential 0
°
(
θ
°
(
θ
)- and 90
°
(
θ
)-exposures. The first 0
°
(
θ
)-exposure induces
Search WWH ::
Custom Search