368
double bonds (Finkelman 1987; Percec and Hahn 1989; Boileau and Teyssié 1991;
Percec and Wang 1992; Białecka-Florjańczyk et al. 1995; Zhang et al. 1996; Dai
et al. 1997; Wan et al. 1998; Mery et al. 1999; Ganicz and Stańczyk 2003; Hu et al.
2003; Yao et al. 2005; Zheng et al. 2005; Zhang et al. 2006; Ahsan et al. 2007; Pan
et al. 2007; Kim et al. 2008; Han et al. 2008; Shibaev and Boiko 2009).
The silicone-based LC polymers with variable isotropic phase transition temperatures (T i ) have been synthesized from PMHS, 10-undecenoic acid-based crosslinking agent and cholesterol-based side chain mesogen (Jana et al. 2011). Side-chain
LC polysiloxanes were synthesized by cohydrosilylation of two mesogenes (a dyemonomer and LC monomer) with PMHS (Jia et al. 2003) or hydrosilylation of five
chiral LC monomers with PMHS. A flexible siloxane backbone and a long flexible
spacer led to a low T g , high thermostability and wide mesophase temperature range
(Zhang et al. 2007a). Other LCs were obtained from reaction of a cholesteric LC
monomer or a fluorinated nematic LC monomer with PMHS. These LC polymers
showed a smectic LC phase with very wide temperature ranges in the heating and
cooling cycles (Han et al. 2008). LC cyclosiloxanes with a very wide smectic-A
range were prepared by adding spacers containing fluorine atoms, with different
lengths, to pentamethylcyclopentasiloxane (D
H 5 ) (Kaneko et al. 2007).
New side chain LC polysiloxanes were synthesized by adding two vinylfunctional LC monomers into PMHS. The LCs with fluorinated mesogen showed
improved thermal stability (T 5 > 300 °C) (Meng et al. 2009). A LC side chain polysiloxane with 5-(pentyloxy)-3-methyloxy-9,10,16,17,23,24-hexakis(octenyloxy)
phthalocyanine groups was prepared by the hydrosilylation reaction of PMHS with
phthalocyanine having a single end alkenyloxy group, in toluene, and using the
catalyst Pt 2 [(ViSiMe 2 ) 2 O] 3 (Ganicz et al. 2012). The LC polysiloxanes obtained
from the reaction of PMHS with novel chiral LC monomers showed a high thermostability and wide mesophase temperature ranges (Wang and Zhang 2014).
The LC silsesquioxanes were also prepared by the hydrosilylation reaction of
Q 8 M
H 8 with alkene (Zhang et al. 2001) or allyloxy (Ba et al. 2003) functionalized
mesogens. The LC cubes had an average of five linked LC groups. Some LC-cube
derivatives showed LC transitions, with a tendency to form spinal muscular atrophy
(SmA) phase (Ba et al. 2003). A LC discotic side chain ladder-like polysiloxane
derivative was obtained by the hydrosilylation of vinyl functional ladder silsesquioxane with Si-H end triphenylene-containing mesogen (Białecka-Florjańczyk and
Sołtysiak 2010). The LC dendritic polymers of regular structure were prepared from
the reaction of the allyl functional carbosilane dendritic matrix of a first generation
with Si-H end cyanobiphenyl, methoxy-phenyl benzoate and cholesteryl mesogens
(Białecka-Florjańczyk and Sołtysiak 2010). Multimesogen LC materials were
obtained from the Si-H end (disiloxane)alkyl-substituted mesogen with a star
octa[(diallylmethyl)propyl]silane (Ponomarenko et al. 1996).
Carbosilane LC dendrimers from first to fifth generations with 8, 16, 32, 64 and
128, end chiral mesogenic groups, were prepared by coupling Si-H end mesogens
with carbosilane matrices containing end allylic groups, exhibiting T g values around
−5 °C. The LC dendrimers of the generations G-1-G-3 formed a ferroelectric smectic (SmC∗) phase up to ~180 °C, while the LC dendrimers of the generations G-4
and G-5 showed a rectangular columnar mesophase (Zhu et al. 2001).
J. J. Chruściel
double bonds (Finkelman 1987; Percec and Hahn 1989; Boileau and Teyssié 1991;
Percec and Wang 1992; Białecka-Florjańczyk et al. 1995; Zhang et al. 1996; Dai
et al. 1997; Wan et al. 1998; Mery et al. 1999; Ganicz and Stańczyk 2003; Hu et al.
2003; Yao et al. 2005; Zheng et al. 2005; Zhang et al. 2006; Ahsan et al. 2007; Pan
et al. 2007; Kim et al. 2008; Han et al. 2008; Shibaev and Boiko 2009).
The silicone-based LC polymers with variable isotropic phase transition temperatures (T i ) have been synthesized from PMHS, 10-undecenoic acid-based crosslinking agent and cholesterol-based side chain mesogen (Jana et al. 2011). Side-chain
LC polysiloxanes were synthesized by cohydrosilylation of two mesogenes (a dyemonomer and LC monomer) with PMHS (Jia et al. 2003) or hydrosilylation of five
chiral LC monomers with PMHS. A flexible siloxane backbone and a long flexible
spacer led to a low T g , high thermostability and wide mesophase temperature range
(Zhang et al. 2007a). Other LCs were obtained from reaction of a cholesteric LC
monomer or a fluorinated nematic LC monomer with PMHS. These LC polymers
showed a smectic LC phase with very wide temperature ranges in the heating and
cooling cycles (Han et al. 2008). LC cyclosiloxanes with a very wide smectic-A
range were prepared by adding spacers containing fluorine atoms, with different
lengths, to pentamethylcyclopentasiloxane (D
H 5 ) (Kaneko et al. 2007).
New side chain LC polysiloxanes were synthesized by adding two vinylfunctional LC monomers into PMHS. The LCs with fluorinated mesogen showed
improved thermal stability (T 5 > 300 °C) (Meng et al. 2009). A LC side chain polysiloxane with 5-(pentyloxy)-3-methyloxy-9,10,16,17,23,24-hexakis(octenyloxy)
phthalocyanine groups was prepared by the hydrosilylation reaction of PMHS with
phthalocyanine having a single end alkenyloxy group, in toluene, and using the
catalyst Pt 2 [(ViSiMe 2 ) 2 O] 3 (Ganicz et al. 2012). The LC polysiloxanes obtained
from the reaction of PMHS with novel chiral LC monomers showed a high thermostability and wide mesophase temperature ranges (Wang and Zhang 2014).
The LC silsesquioxanes were also prepared by the hydrosilylation reaction of
Q 8 M
H 8 with alkene (Zhang et al. 2001) or allyloxy (Ba et al. 2003) functionalized
mesogens. The LC cubes had an average of five linked LC groups. Some LC-cube
derivatives showed LC transitions, with a tendency to form spinal muscular atrophy
(SmA) phase (Ba et al. 2003). A LC discotic side chain ladder-like polysiloxane
derivative was obtained by the hydrosilylation of vinyl functional ladder silsesquioxane with Si-H end triphenylene-containing mesogen (Białecka-Florjańczyk and
Sołtysiak 2010). The LC dendritic polymers of regular structure were prepared from
the reaction of the allyl functional carbosilane dendritic matrix of a first generation
with Si-H end cyanobiphenyl, methoxy-phenyl benzoate and cholesteryl mesogens
(Białecka-Florjańczyk and Sołtysiak 2010). Multimesogen LC materials were
obtained from the Si-H end (disiloxane)alkyl-substituted mesogen with a star
octa[(diallylmethyl)propyl]silane (Ponomarenko et al. 1996).
Carbosilane LC dendrimers from first to fifth generations with 8, 16, 32, 64 and
128, end chiral mesogenic groups, were prepared by coupling Si-H end mesogens
with carbosilane matrices containing end allylic groups, exhibiting T g values around
−5 °C. The LC dendrimers of the generations G-1-G-3 formed a ferroelectric smectic (SmC∗) phase up to ~180 °C, while the LC dendrimers of the generations G-4
and G-5 showed a rectangular columnar mesophase (Zhu et al. 2001).
J. J. Chruściel