Linear and hyperbranched liquid crystalline polysiloxanes

Novel oligocarbosilazanes bearing promesogenic end groups

“…The hydrosilylation reactions leading to the formation of oligocarbosilazanes bearing promesogenic end groups were performed following a procedure described previously with some minor changes [7]. In a typical experiment, 1 g (1.84 mmol) of mesogen B (see Figure 3), 1,1,3,3-tetramethyl-1-[5-(4′-undecyloxy-biphenyl-4-yloxy)-pentyl]-disiloxane) was dissolved in toluene (10 ml) in a flame-dried Schlenk tube equipped with an argon inlet.…”

“…The reaction was monitored by FTIR, through the disappearance of the Si-H stretching band at 2130 cm -1 . The reaction conditions were typical for this type of process [7]. All the syntheses were carried out at 60°C in toluene under an inert atmosphere ( Figure 3).…”

“…Although both starting mesogens exhibit LC properties in a free form [8,9], it was previously found that mesogen A, when attached as a side chain to polymers with relatively low molar ratio of functional units, produced materials with poor or even no LC properties [5,7,8]. Therefore, during the course of our research, we directed our attention to mesogen B which was reported to be more effective in systems with a low degree of functionalization [7,9]. In the case of samples B1 and B2, small birefringent droplets 'dissolved' in an amorphous phase were observed by POM ( Figure 5).…”

Side-Chain Liquid Crystal Conducting Polymers

“…6 An example was reported by Wang et al 7 , who synthesised a liquid crystalline polysiloxane with a grafted biphenyl mesogenic side-chain (Figure 2). Both the monomer and the grafted polymer had liquid crystalline properties, without any need for a large fraction of the siloxane units to have mesogenic substituents.…”

Hyperbranched polysiloxane functionalized graphene oxide for dicyclopentadiene bisphenol dicyanate ester nanocomposites with high performance

“…Anchoring the hyperbranched polymers on the silica nanoparticles [23] and carbon nanotubes [24] has been studied for improving solubility of the inorganic materials, and the obtained hybrid nanoparticles exhibited some novel properties. Among reported hyperbranched polymers so far, hyperbranched polysiloxanes are beginning to attract interests as new organic inorganic hybrid materials because they combine the unique chemical structure of polysiloxane and hyperbranched topology structure, and thus possess low viscosity, high reactivity, low surface energy and interface tension [25,26]. Gu's group [27][28][29] investigated the effects of hyperbranched polysiloxane on the properties of cyanate ester resin, and the results show that hyperbranched polysiloxane has good compatibility with cyanate ester matrix and the incorporation of hyperbranched polysiloxane in cyanate ester leads to an obvious improvement in the mechanical and thermal properties.…”