366
M. Funahashi
Fig. 18.7 Molecular structures of perylene bisimide derivatives bearing cyclotetrasiloxane rings
and their phase transition property
nanosegregated structures were retained during the photopolymerization process.
However, terminal polymerizable groups sometimes inhibit the formation of LC
phases and do not increase solubility sufficiently.
Cyclotetrasiloxane moieties polymerize in the presence of an acid or base catalyst in solution states. However, they are inactive to UV light illumination and the
photopolymerization method could not be adopted.
We synthesized perylene bisimide derivatives 7 and 8 which have four cyclotetrasiloxane rings at the terminals of alkyl chains (Fig. 18.7). The cyclotetrasiloxane
ring is very bulky compared to conventional alkyl side chains; nevertheless, these
compounds exhibit columnar phases at room temperature [30].
TOF measurements revealed a high electron mobility exceeding 0.1 cm
2 /Vs in
the columnar phase of compound 8 at room temperature. In spite of the presence
of the bulky cycloterasiloxane rings, π-conjugated units are closely organized and
form crystal-like order in the columnar phase.
The solubilities of these compounds are very high (>30 wt% for n-hexane), and
thin films could be produced by the spin-coating method. On non-treated glass
substrates, thin films with polydomain structures were produced. The domain size
was around several ten μm and columnar aggregates aligned parallel to the surface
of the substrates because of the surface tension at the air-solution interface.
Compound 8 polymerized in solution states in the presence of acid catalysts to
form gelatinous precipitates. However, the precipitates were not soluble in organic
solvents and thin films could not be produced. Figure 18.8a displays a schematic
illustration of the in situ polymerization of the spin-coated film of compound 8. The
spin-coated thin films can be insolubilized by an exposure on acid vapors at 70 °C.
The polymerization in the thin film proceeds via a ring-opening mechanism initiated
by acid vapors. In an IR absorption spectrum of the thin film, only absorption band for
Si–O stretching changed during the polymerization process, which support the ringopening of the cyclotetrasiloxane rings purged into the mantle area of the columnar
M. Funahashi
Fig. 18.7 Molecular structures of perylene bisimide derivatives bearing cyclotetrasiloxane rings
and their phase transition property
nanosegregated structures were retained during the photopolymerization process.
However, terminal polymerizable groups sometimes inhibit the formation of LC
phases and do not increase solubility sufficiently.
Cyclotetrasiloxane moieties polymerize in the presence of an acid or base catalyst in solution states. However, they are inactive to UV light illumination and the
photopolymerization method could not be adopted.
We synthesized perylene bisimide derivatives 7 and 8 which have four cyclotetrasiloxane rings at the terminals of alkyl chains (Fig. 18.7). The cyclotetrasiloxane
ring is very bulky compared to conventional alkyl side chains; nevertheless, these
compounds exhibit columnar phases at room temperature [30].
TOF measurements revealed a high electron mobility exceeding 0.1 cm
2 /Vs in
the columnar phase of compound 8 at room temperature. In spite of the presence
of the bulky cycloterasiloxane rings, π-conjugated units are closely organized and
form crystal-like order in the columnar phase.
The solubilities of these compounds are very high (>30 wt% for n-hexane), and
thin films could be produced by the spin-coating method. On non-treated glass
substrates, thin films with polydomain structures were produced. The domain size
was around several ten μm and columnar aggregates aligned parallel to the surface
of the substrates because of the surface tension at the air-solution interface.
Compound 8 polymerized in solution states in the presence of acid catalysts to
form gelatinous precipitates. However, the precipitates were not soluble in organic
solvents and thin films could not be produced. Figure 18.8a displays a schematic
illustration of the in situ polymerization of the spin-coated film of compound 8. The
spin-coated thin films can be insolubilized by an exposure on acid vapors at 70 °C.
The polymerization in the thin film proceeds via a ring-opening mechanism initiated
by acid vapors. In an IR absorption spectrum of the thin film, only absorption band for
Si–O stretching changed during the polymerization process, which support the ringopening of the cyclotetrasiloxane rings purged into the mantle area of the columnar