Side-chain Liquid Crystalline Polysiloxanes Research Articles

Side chain liquid crystalline polysiloxane hydroxamic acids and their liquid crystalline behaviour

The synthesis and properties of side chain polysiloxane hydroxamic acids have been described. The N-p substituted phenyl hydroxamic acids were synthesized by reacting p - allyloxy benzoyl chloride and acryloyloxy sebacoyl chloride with N-arylhydroxylamines in toluene medium, rendered basic with aqueous suspension of sodium bicarbonate at 0 °C or lower. The synthesized N-phenyl substituted hydroxamic acids were attached to poly(methylhydrosiloxane) via hydrosilylation reaction in the presence of platinum catalyst The polysiloxane hydroxamic acids were characterized by melting point, FT – IR, NMR and Mass spectral techniques. The liquid crystalline behaviour of the side chain polysiloxane hydroxamic acids with allyloxy and acryloylsebacoyloxy spacer have been studied by optical.polansed microscopy and differential scanning calorimetry. Side chain liquid crystalline polysiloxane hydroxamic acids with allyloxy spacer (N-p substituted phenyl p-[(3-polysiloxane propyloxy) benzo] hydroxamic acids, (PHA – 1 to PHA −4) show nematic phases, while the second series with acryloylsebacoyloxy spacer (N-p-substituted phenyl (3-polysiloxane propanone) octyl carbonyloxy hydroxamic acids, (PHA – 5 to PHA – 8) show nematic as well as smectic phases. The liquid crystalline behaviour of the side chain polysiloxane hydroxamic acids with allyloxy and acrylsebacoyloxy spacer have been studied.

Design and Investigation of a Side-Chain Liquid Crystalline Polysiloxane with a Ntb-Phase-Forming Side Chain

A new mesogenic non-symmetric dimeric monomer with a terminal olefin function, forming a twist bend nematic (Ntb) as well as a nematic (N) phase, was synthesized, using an enhanced synthetic methodology, which avoids isomerization of the terminal double bond in the preparation of the dimer. This monomer was attached to a pentamethyldisiloxane group, resulting in the SmA LC phase behavior of the ensuing material. Linking the monomer to a siloxane main chain resulted in nematic phase behavior. Detailed studies with the Ntb phase forming dimer DTC5C7 show full miscibility of the dimer and the new LC polymer in the LC state, suggesting that the side-chain LC polymer forms a Ntb phase as the low-temperature nematic phase. Copolymerizing the monomer with a cyanobiphenyl-based monomer allows us to tune the glass transition and phase behavior further.

High intrinsic thermally conductivity side-chain liquid crystalline polysiloxane films grafted with pendent difunctional mesogenic groups

Herein, the microscopic ordered aggregation morphologies of SCLCP films are investigated, and molecular structures with regular arrangement can increase heat transfer via suppressing the scattering of phonons, thus greatly improving the λ of SCLCPs.

A series of novel side chain liquid crystalline polysiloxanes containing cyano‐ and cholesterol‐terminated substituents: Where will the structure‐dependence of terminal behavior of the side chain reappear?

ABSTRACTA series of polysiloxane side chain liquid crystal polymers with strong polarity cyano substitution‐terminated achiral side chains and cholesterol‐terminated chiral side chains was successfully synthesized via thiol‐ene click chemistry. 1H‐NMR, FT‐IR, and thermogravimetric analysis were used to confirm their chemical structures and thermal stabilities. Their phase transition behaviors and phase structures were systematically investigated by a combination of analysis methods such as differential scanning calorimetry, polarized optical microscopy, and X‐ray. Results revealed that attributing to the decisive role of the polarity interaction, all the polymers only developed a monolayer interdigitated SmA phase in which the period arrangement was determined by the cyano‐terminated side chains, the increased content of cholesterol‐terminated chiral side chains (Xchol) just expanded the distance between neighboring molecules within a layer. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1765–1772

PB12 側鎖型液晶性ポリシロキサンのER効果に及ぼす側鎖末端基の影響(化学・材料)

PB12 側鎖型液晶性ポリシロキサンのER効果に及ぼす側鎖末端基の影響(化学・材料)

Cholesteric Cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes

Two new kinds of Cholesteric cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes (PAand PB) were synthesized via hydrosilylation reaction of polymethyl hydrogen siloxane with cyclohexane mesogenic monomers (MAand MB). The yield of PA, PBwere 71.6%, 82.5% and 81.0%, respectively. The molecular structures of MAand MB, PAand PBwere investigated by Fourier transform infrared spectroscopy (FTIR) and hydrogen-nuclear magnetic resonance spectra (1H-NMR). The corresponding liquid crystalline phase type was also observed by polarizing optical microscopy (POM) and X-ray diffraction (XRD). The liquid crystalline phase behavior and thermal properties of the polymers were analyzed by differential scanning calorimetry (DSC). Results showed that MAand MBexhibited multicolor platelet texture of a blue phase and cholesteric phase, and the Tmand Tiof MAand MBincreased with the increasing flexible chain length. The mesophase temperature range of PAand PBwas broader than that of MAand MB. PAexhibited a rare nematic phase----spherulite texture of polymeric smectic A phase. PBwere of cholesteric and nematic---- cholesteric phase. The Tmand Tiof PAand PBincreased with the increasing flexible spacer groups.

Synthesis and characterization of a graft side-chain liquid crystalline polysiloxane

A graft side-chain crystalline polymer PI with polysiloxane as backbone and a liquid crystal polymer, poly{6-(4′-octyloxyphenyl-4″-benzoyl)hexyl acrylate}, as side chain has been synthesized via atom transfer radical polymerization (ATRP) technique. Attaching mesogenic polymers to the polysiloxane main chain through ATRP technique brings about the high density of mesogenic units and avoids the subsequent crosslinking reaction by the residual Si–H in the traditional hydrosilylation. The properties of the graft liquid crystal polymer PI was studied in detail by TGA, DSC, POM and XRD. Thermal analysis shows that the polymer PI has wider mesophase temperature ranges with a high thermal stability in comparison to its mesogenic monomer.

Liquid Crystalline Polymer–Co Nanorod Hybrids: Structural Analysis and Response to a Magnetic Field

This work deals with the structural analysis of side-chain liquid crystalline polysiloxanes, doped with magnetic cobalt nanorods, and their orientational properties under a magnetic field. These new materials exhibit the original combination of orientational behavior and ferromagnetic properties at room temperature. Here we show that, within the liquid crystal polymer matrix, the cobalt nanorods self-assemble in bundles made of nanorod rows packed in a 2-dimensional hexagonal lattice. This structure accounts for the magnetic properties of the composites. The magnetic and orientational properties are discussed with respect to the nature of the polymer matrix.

Synthesis and properties of novel chiral side-chain liquid crystalline polysiloxanes containing different chiral pendant groups

Two novel chiral liquid crystalline monomers, and a series of their corresponding chiral side-chain polymers (P1–P7) based on poly(methylhydrogeno)siloxane have been prepared. The chemical structures and liquid crystalline properties of the synthesized monomers and polymers have been investigated using various experimental techniques. Thermal analysis shows that all polymers have wide mesophase temperature ranges with a high thermal stability. With the increase of M2 molar ratio in the polymer systems, the isotropic phase transition and glass transition temperatures of all polymers increase, and the temperature ranges of N* phase and mesophase become broad. The effect of cholesteryl mesogens on mesophase behaviors, optical properties, and molecular arrangement of LC polysiloxanes and their advanced applications have also been discussed. For homopolymer P1, it shows a single SA phase. With increasing the content of M2 in the polymer systems, P2 and P3 reveal a SA–N* phase transition when they are heated, and P4–P7 reveal a N* phase. For N* phase polymers P4–P7, the reflection wavelengths exhibit blue shift, suggesting that the pitch decreases with a decrease in the amount of the smectic domains induced by the M1. The reflection wavelengths of P4–P7 are almost across the entire visible region when they are heated, which offer stremendous potential for various optical applications. For P2 and P3, the reflection wavelengths show a very steep change around the temperature of the SA–N* phase transition, which can be used as thermally sensitive liquid crystal devices requiring fast response, such as sensors, and thermally induced tuning.

3-Hydroxy-4-[(phenylimino)methyl]phenyl 4-(Hexadecanoyloxy)benzoate

A new Schiff base ester, 3-hydroxy-4-[(phenylimino)methyl]phenyl 4-(hexadecanoyloxy)benzoate was synthesized and its IR, 1H-NMR, 13C-NMR and MS spectroscopic data are presented.

Properties Research on Chiral Liquid Crystalline Polysiloxanes Containing Chiral and Electron Withdrawing Group

A series of new chiral side-chain liquid crystalline polysiloxanes(P0-P7) bearing cyano groups were synthesized with a cholesteric LC monomer and a nematic monomer with cyano units(electron withdrawing). The chemical structures and LC properties of the polymers were measured by spectrum and thermal analysis techniques. The obtained polymers were soluble in many solvents and the specific rotations showed negative values and increased with the increasing content of chiral reagent. P1 showed grained texture of smectic A, P2~P7 showed lined texture of chiral smectic C(SC*). XRD curves of P1~P7 samples showed sharp and strong peaks at low angle, but no sharp peak was seen for P0 sample. The temperatures at which 5% weight loss occurred(Td) were greater than 300oC for all the polymers, which reveals all the polymers were stable. And the Tg values of polymers were all low. The Tg and Ti values are all increased with the increasing chiral contents. All the polymers displayed wide range of liquid crystal phase on heating and cooling cycle.

Synthesis and Characterisation of Side-Chain Liquid-Crystalline Polysiloxane Exhibiting Spherulite Texture of Polymeric Smectic a Phase

A new type of side-chain liquid-crystalline polysiloxane was synthesised by graft copolymerisation, using (trans, trans)-4-propyl-4'-vinylbicyclohexane exhibiting platelet texture of a blue phase as a mesogenic monomer. The graft copolymerisation was confirmed by characterising the chemical structure of the mesogenic monomer and the polymer by FT-IR, 1H NMR and 13C NMR. Microstructures of the mesogenic monomer and the polymer were analysed by polarising optical microscopy and X-ray diffraction. Thermal properties of the mesogenic monomer and the polymer were studied by differential scanning calorimetry (DSC). Meanwhile, the spherulite texture of the polymeric smectic A phase of the mesogenic polymer was revealed in the cooling process by polarising optical microscopy. This texture is uncommon in other liquid crystalline polymers.

Study on the Properties of Mesogenic Monomer Exhibiting Blue Phase and Synthesis of Side-Chain Liquid-Crystalline Polysiloxanes

A new type of Side-Chain Liquid-Crystalline Polysiloxanes was synthesized by graft polymerization, using (Trans, trans)- 4-propyl-4’-vinyl-bicyclohexane(3HHV) with platelet texture of a blue phase as mesogenic monomer. Microstructure of monomer and polymer were analyzed by polarizing optical microscopy and X-ray diffraction. Thermal properties of monomer and polymer were researched by differential scanning calorimetry. Meanwhile, spherulite texture of polymeric smectic A phase of liquid crystal polymer was revealed in the cooling cycle by polarizing optical microscopy, and this texture was so uncommon that can hardly be found in the liquid crystalline polymers.

Synthesis and characterization of side-chain liquid crystalline polymers and oriented elastomers containing terminal perfluorocarbon chains

Several novel chiral side-chain liquid crystalline (LC) polysiloxane resins containing epoxy groups and mesogenic components have been graft copolymerized by a one-step hydrosilylation reaction with poly(methylhydrogeno)siloxane, an epoxy monomer 2-(allyloxymethyl)oxirane, and chiral fluorinated liquid-crystalline monomers 4′-(4-(allyloxy)benzoyloxy)biphenyl-4-yl 6-(perfluorooctanoyloxy)hexahydrofuro[3,2-b]furan-3-yl adipate and 4′-(4-(undec-10-enoyloxy)benzoyloxy)biphenyl-4-yl 6-(perfluorooctanoyloxy)hexahydrofuro[3,2-b]furan-3-yl adipate. The synthesized epoxy resins are cured using 4,4′-diaminodiphenyl-methane in mesophase state under a magnetic field to obtain crosslinked oriented elastomers. The chemical structures, LC properties and surface morphology of the monomers, the resins and the liquid crystalline elastomers (LCEs) are characterized by use of various experimental techniques such as FTIR, 1H NMR, EA, TGA, DSC, POM, and X-ray measurements. The mesomorphic properties of the synthesized resins and corresponding oriented elastomers are influenced by the terminal perfluorocarbon chains components effectively. The resins show chiral nematic and chiral smectic C phases (Sc*), and Sc* are frozen in their corresponding oriented elastomers. The LC phases are verified by X-ray measurements, and the orientational order parameters of the oriented LCEs are calculated as well.

偏振光照对偶氮苯侧链聚硅氧烷膜表面能的提高

Azobenzene containing side-chain liquid crystalline polymer was synthesized by hydrosilation reaction of poly(methylhydrosiloxane) with the azo monomer.The chemical structure and its liquid crystalline properties were investigated by FITR,DSC and POM with a hot stage.Photo-alignment treatment was performed on the polysiloxane film by using a linearly polarized light source with the wavelength of 473 nm.A static contact angle mea-surement was carried out and the surface free energy was also calculated from the contact angles of a drop of water on the polymer film.The water contact angles was decreased from 94.5° to 76.5° after the light irradiation.We conclude that the changes in the hydrophilic of LC polymer were influenced by the surface compositions upon the photoinduced reorientation of the azobenzene side groups perpendicularly towards the film surface,which was confirmed by conoscopic POM observation results.

Effect of chiral isosorbide groups on mesomorphic properties of side-chain liquid-crystalline polysiloxanes

Chiral side-chain liquid-crystalline (LC) polysiloxanes containing isosorbide groups were graft copolymerised with poly(methylhydrogeno)siloxane, a chiral LC monomer 6-(4-methoxy-benzoyloxy)-hexahydro-furo[3,2-b]furan-3-yl 4'-(4-undec-10-enoyloxy-benzoyloxy)-biphenyl-4-yl adipate and a nematic LC monomer 4'-(4-methoxy-benzoyloxy)-biphenyl-4-yl 4-(2-undec-10-enoyloxy-ethoxy)-benzoate. The chemical structures and LC properties of the monomers and polymers were characterised by use of various experimental techniques including Fourier transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance (NMR), element analyses (EA), differential scanning calorimetry (DSC), polarised optical microscopy (POM) and X-ray diffraction (XRD). All the chiral LC polymers showed LC properties with very wide mesophase temperature ranges and the chiral component in the LC polymer systems lead to the appearance of a cholesteric phase. The polymers bearing most chiral LC monomer component showed smectic phases by reason of regular structures in the polymer systems. With the increase of another nematic LC monomer in the polymers, the regular polymer structures were destroyed because of different chemical structures between the two kinds of LC monomers, leading to the disappearance of the smectic arrangement.

Sorption Properties of Functionalized Liquid Crystalline Networks

Functionalized polydomain chiral elastomers were obtained by cross-linking side-chain liquid crystalline polysiloxanes bearing acid functions. Sorption experiments were performed by the use of an electronic microbalance, in the presence of one enantiomer of a chiral amine molecule, able to interact with the acid groups. The results showed that Fick's diffusion law is not valid anymore as soon as an interaction between the material and the molecule is present. Moreover, it was demonstrated that the grafting of interacting groups on a chiral elastomer enhanced both the capacity and selectivity toward one enantiomer.

Synthesis and characterization of side-chain liquid-crystalline polysiloxanes containing fluorinated units

Several new chiral side-chain LC polysiloxanes (IP–VIIP) bearing fluorinated methyl groups were synthesized with a cholesteric LC monomer and a non-LC monomer containing fluorinated units. The chemical structures and LC properties of the monomers and polymers were characterized by use of various experimental techniques. The effect of copolymer composition on mesomorphic properties of the fluorine-containing polymers was studied as well. The obtained polymers were soluble in many solvents and the specific rotations showed negative values. The temperatures at which 5% weight loss occurred (Td) were greater than 300 °C for all the polymers and the residue weight on heating to 600 °C increased slightly with increase of the monomer containing fluorinated units in the polymer systems. All the polymers displayed two-phase transitions when they were heated and cooled. The IP, IIP, and IIIP exhibited cholesteric textures when they were heated and cooled, while IVP, VP, VIP, and VIIP showed smectic fan-shaped textures. XRD curves of samples of IVP, VP, VIP, and VIIP displayed sharp and strong peaks at low angle, but no sharp peaks were shown at low angle for the samples IP, IIP, and IIIP.

Chiral side-chain liquid crystalline polysiloxanes bearing fluorinated mesogens and cholesteryl groups

A series of chiral side-chain liquid crystalline (LC) polysiloxanes bearing fluorinated mesogens were synthesized with a cholesteric LC monomer and a fluorinated nematic LC monomer. They were characterized by use of various experimental techniques, and effect of fluorinated mesogens on characteristic of LC polysiloxanes was studied as well. In photoluminescence spectra, a narrow and a broad peak occur at around 270–317 nm, originated, respectively, from fluorinated phenyl groups and the conjugated xenene structure. The specific rotation analysis of all polymers showed negative values, but absolute values were lower than those of the chiral monomers. All polymers showed smectic LC phase with very wide temperature ranges on heating and cooling cycles. Especially, only polymers bearing more fluorinated component exhibited smectic–cholesteric phase transition when they were heated. As the polymers contained more fluorinated mesogens, segregation of the fluorinated segment to the surface should occur at mesomorphic temperature. The highly ordered lamellar mesogen–siloxane matrix systems should be disturbed severely by separation of fluorinated mesogens, suggesting mesogenic orders transition from lamellar smectic to cholesteric phase.

Study on an Electrorheological Effect of Side-Chain Polysiloxanes Including Fluorine Atoms by the Preshearing Method

Side-chain liquid-crystalline polysiloxane derivatives possessing fluorinated mesogens that have positive dielectric-anisotropy parallel to the long axis of mesogen were synthesized to study phase-transition behavior and electrorheological (ER) effect of the polymers with a preshearing method. About 2000 Pa increments in shear stress could be obtained after preshearing as an ER effect. In addition, shear rate dependence on shear stress as a function of temperature was investigated. As a result, it was shown that the preshearing treatment with high shear rate was important to generate a larger ER effect.