Self-oscillating systems abound in the natural world and offer substantial potential for applications in controllers,micro-motors,medical equipments,and so on.Currently,numerical methods have been widely utilized for ...Self-oscillating systems abound in the natural world and offer substantial potential for applications in controllers,micro-motors,medical equipments,and so on.Currently,numerical methods have been widely utilized for obtaining the characteristics of self-oscillation including amplitude and frequency.However,numerical methods are burdened by intricate computations and limited precision,hindering comprehensive investigations into self-oscillating systems.In this paper,the stability of a liquid crystal elastomer fiber self-oscillating system under a linear temperature field is studied,and analytical solutions for the amplitude and frequency are determined.Initially,we establish the governing equations of self-oscillation,elucidate two motion regimes,and reveal the underlying mechanism.Subsequently,we conduct a stability analysis and employ a multi-scale method to obtain the analytical solutions for the amplitude and frequency.The results show agreement between the multi-scale and numerical methods.This research contributes to the examination of diverse self-oscillating systems and advances the theoretical analysis of self-oscillating systems rooted in active materials.展开更多
In this paper,we are concerned with a three-dimensional non-isothermal model for the compressible nematic liquid crystal flows in a periodic domain.Under some smallness and structural assumptions imposed on the time-p...In this paper,we are concerned with a three-dimensional non-isothermal model for the compressible nematic liquid crystal flows in a periodic domain.Under some smallness and structural assumptions imposed on the time-periodic force,we establish the existence of the time-periodic solutions to the system by using a regularized approximation scheme and the topological degree theory.We also prove a uniqueness result via energy estimates.展开更多
In this paper,we establish some regularity conditions on the density and velocity fields to guarantee the energy conservation of the weak solutions for the three-dimensional compressible nematic liquid crystal flow in...In this paper,we establish some regularity conditions on the density and velocity fields to guarantee the energy conservation of the weak solutions for the three-dimensional compressible nematic liquid crystal flow in the periodic domain.展开更多
Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since...Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.展开更多
Spatial light modulators,as dynamic flat-panel optical devices,have witnessed rapid development over the past two decades,concomitant with the advancements in micro-and opto-electronic integration technology.In partic...Spatial light modulators,as dynamic flat-panel optical devices,have witnessed rapid development over the past two decades,concomitant with the advancements in micro-and opto-electronic integration technology.In particular,liquid-crystal spatial light modulator(LC-SLM)technologies have been regarded as versatile tools for generating arbitrary optical fields and tailoring all degrees of freedom beyond just phase and amplitude.These devices have gained significant interest in the nascent field of structured light in space and time,facilitated by their ease of use and real-time light manipulation,fueling both fundamental research and practical applications.Here we provide an overview of the key working principles of LC-SLMs and review the significant progress made to date in their deployment for various applications,covering topics as diverse as beam shaping and steering,holography,optical trapping and tweezers,measurement,wavefront coding,optical vortex,and quantum optics.Finally,we conclude with an outlook on the potential opportunities and technical challenges in this rapidly developing field.展开更多
Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely a...Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely applied in flat panel display industries and inspires the wavefront modulation with the development of LC alignment techniques.However,most LC elements perform only one type of optical manipulation and are difficult to realize the multifunctionality and light integration.Here,flat multifunctional liquid crystal elements(FMLCEs),merely composed of anisotropic LC molecules with space-variant orientations,are presented for multichannel information manipulation by means of polarization,space and wavelength multiplexing.Specifically,benefiting from the unique light response with the change of the incident polarization,observation plane,and working wavelength,a series of FMLCEs are demonstrated to achieve distinct near-and far-field display functions.The proposed strategy takes full advantage of basic optical parameters as the decrypted keys to improve the information capacity and security,and we expect it to find potential applications in information encryption,optical anti-counterfeiting,virtual/augmented reality,etc.展开更多
We consider the Poiseuille flow of nematic liquid crystals via the full Ericksen-Leslie model.The model is described by a coupled system consisting of a heat equation and a quasilinear wave equation.In this paper,we w...We consider the Poiseuille flow of nematic liquid crystals via the full Ericksen-Leslie model.The model is described by a coupled system consisting of a heat equation and a quasilinear wave equation.In this paper,we will construct an example with a finite time cusp singularity due to the quasilinearity of the wave equation,extended from an earlier resultonaspecial case.展开更多
A series of bowlic cyclotriveratrylenes(CTV) with peripheral groups with different lengths were synthesized.These compounds were investigated by diferential scanning calorimetry and hot stage coupled polarizing micr...A series of bowlic cyclotriveratrylenes(CTV) with peripheral groups with different lengths were synthesized.These compounds were investigated by diferential scanning calorimetry and hot stage coupled polarizing microscopy.Several CTV derivatives show thermotropic liquid crystalline properties.The experimental results of their thermotropic liquid crystalline behavior indicate that the clear points,the entropy changes of melting points,the crystallization temperatures,and their entropy changes all exhibited an evident odd-even effect except the melting points,which decreased monotonously with the increase of the length of the alkoxy groups.The parameter values of CTVs with even number carbon atoms were larger than those of CTVs with odd number.When the length of alkoxyl chains was even longer,a monotonous decrease occured.Nevertheless,in the case of the entropy changes of both melting points and crystallization temperatures,the effect was valid for all the six species,and therefore,the whole curves presented as a zig-zag form.展开更多
This article is devoted to the study of the so-called incompressible limit for solutions of the compressible liquid crystals system. We consider the problem in the whole space R^N and a bounded domain of R^N with Diri...This article is devoted to the study of the so-called incompressible limit for solutions of the compressible liquid crystals system. We consider the problem in the whole space R^N and a bounded domain of R^N with Dirichlet boundary conditions. Here we set the number of dimension N = 2 or 3.展开更多
The planar texture of glassy cholesteric siloxane cyclic side-chain liquid crystals was fixed by quenching initially. Then the polymer network formed by the optically active polymerizable monomers imposed additional c...The planar texture of glassy cholesteric siloxane cyclic side-chain liquid crystals was fixed by quenching initially. Then the polymer network formed by the optically active polymerizable monomers imposed additional constraints on the motion of chain segments of the glassy liquid crystal and then further stabilized the molecule arrangement. A cholesteric liquid crystal film with stable optical properties was developed by this method.展开更多
A new liquid crystalline polyacetylene containing a phenyl benzoate mesogen (5) is synthesized,whose mesomorphic properties are found to be easily 'tunab1e' by simple mechanical perturbation. Thepolymerization...A new liquid crystalline polyacetylene containing a phenyl benzoate mesogen (5) is synthesized,whose mesomorphic properties are found to be easily 'tunab1e' by simple mechanical perturbation. Thepolymerization of 10- [ 4 - (4' -methoxyphenoxycarbonyl )phenoxycarbonyl] - 1 -decyne (4 ) in itiated by theWCl_6-Ph_4Sn/dioxane complex yields polymer 5 with a M_w of 28400. The molecular structure of 5 ischaracterized by NMR, IR, and UV spectroscopy and its liquid crystalline behavior is investigated by DSC,POM, and XRD analysis. Upon mechanical perturbation, 5 exhibits unusual agitation-induced high-strengthdisclinations, shear-induced inversion walls, and solidification-induced banded textures. Such phenomenahave been observed in the main-chain liquid crystalline polymers with rigid backbones, but have seldom beenreported for the side-chain liquid crystalline polymers with flexible backbones, suggesting that the rigidpolyacetylene backbone of 5 plays a constructive role in inducing the novel molecular alignments.展开更多
In this work, negative dielectric nematic liquid crystal SLC 12V620-400, chiral dopant S811, and laser dye DCM are used to prepare dye-doped chiral nematic liquid crystal laser sample. In order to investigate temperat...In this work, negative dielectric nematic liquid crystal SLC 12V620-400, chiral dopant S811, and laser dye DCM are used to prepare dye-doped chiral nematic liquid crystal laser sample. In order to investigate temperature-tunable lasing in negative dielectric chiral nematic liquid crystal, we measure the transmission and lasing spectrum of this sample. The photonic band gap (PBG) is observed to red shift with its width reducing from 71.2 nm to 40.2 nm, and its short-wavelength band edge moves 55.3 nm while the long-wavelength band edge only moves 24.9 nm. The wavelength of output laser is found to red shift from 614.4 nm at 20 ~C to 662.8 nm at 67 ~C, which is very different from the previous experimental phenomena. The refractive indices, parallel and perpendicular to the director in chiral nematic liquid crystal have different dependencies on temperature. The experiment shows that the pitch of this chiral nematic liquid crystal increases with the increase of temperature. The decrease in the PBG width, different shifts of band edges, and the red shift of laser wavelength are the results of refractive indices change and pitch thermal elongation.展开更多
Some diacetylene-containing copolyesters with different ratios of dipropargyl 1,10-decanate anddipropargyl terephthalate were synthesized. Properties of these copolymers were characterized by differentialscanning calo...Some diacetylene-containing copolyesters with different ratios of dipropargyl 1,10-decanate anddipropargyl terephthalate were synthesized. Properties of these copolymers were characterized by differentialscanning calorimetry and polarizing optical microscopy. The copolymer could be cross-linked easily by UVirradiation in a liquid crystal matrix without adding any photoinitiator. The preliminary studies showed thatthe diacetylene-containing polymer network can assist liquid crystal molecules to align with the externalelectric field, thus reducing the response time of display devices.展开更多
The synthesis and phase behaviour of chiral combined main/side chain liquid crystallinecopolymers containing pendant group constituted by chiral side group and trans-azobenzenemoiety with nitro end group are described...The synthesis and phase behaviour of chiral combined main/side chain liquid crystallinecopolymers containing pendant group constituted by chiral side group and trans-azobenzenemoiety with nitro end group are described. The formation of liquid crystalline polymorphism ofcopolymers is influenced by various contents of achiral side group.展开更多
The dynamic response of molecular orientation, and the temperature and pulse shape dependences of the switching behavior in ferroelectric liquid crystal are described. The switching speed and the surface energy of fer...The dynamic response of molecular orientation, and the temperature and pulse shape dependences of the switching behavior in ferroelectric liquid crystal are described. The switching speed and the surface energy of ferroelectric liquid crystal are given.展开更多
Two series of novel cholesteryl-containing H-bonded liquid crystals were prepared through facile self-assembly between cholesteryl isonicotinate (proton acceptor) exhibiting a monotropic cholesteric phase, and the 4...Two series of novel cholesteryl-containing H-bonded liquid crystals were prepared through facile self-assembly between cholesteryl isonicotinate (proton acceptor) exhibiting a monotropic cholesteric phase, and the 4-alkoxy-benzoic acid or 4-alkoxy cinnamic acid (proton donor). It was found that the increase of the conjugate length as well as the terminal length can contribute to enhance the interaction of molecules and thus significantly influenced the thermal behaviors of H-bonded LCs. The cholesteric reflection spectra of the induced mesogenic complexes were located in the visible region with the color tuneable thermo-sensitivity, which could be used for display application.展开更多
A mechanical model of liquid crystals (LCs) is applied to study the polymorphism of homologous series of terphenyl compounds. With a senti-experimental molecular orbit method, we calculate the moment of inertia whic...A mechanical model of liquid crystals (LCs) is applied to study the polymorphism of homologous series of terphenyl compounds. With a senti-experimental molecular orbit method, we calculate the moment of inertia which represents the rotation state to describe the phase transition temperature obtained from experimental data. We propose a novel explanation of the phase sequence or polymorphism of LC materials using the two key parameters, the moment of inertia and critical rotational velocity. The effect of molecular polarity on the appearance of liquid crystalline is also discussed.展开更多
Transition metal complexes of meso-tetra(4-myristyloxyphenyl)porphyrin TMPPM [M =Mn, Fe, Co, Ni, Cu, Zn; TMPP=mesotetra(4-myristyloxyphenyl)porphyrin] have been synthesized and characterized by means of elemental an...Transition metal complexes of meso-tetra(4-myristyloxyphenyl)porphyrin TMPPM [M =Mn, Fe, Co, Ni, Cu, Zn; TMPP=mesotetra(4-myristyloxyphenyl)porphyrin] have been synthesized and characterized by means of elemental analyses, UV-Vis spectra, infrared photoacoustic spectra, 1H NMR spectra, molar conductance and differential scanning calorimetry(DSC). The ligand and the Zn complex show liquid crystalline behavior. According to the DSC thermogram of the Zn complex, it exhibits a lower phase transition temperature -7.453 ℃ and a wide mesophase temperature span, 77 ℃.展开更多
In this article, we prove the global existence of weak solutions to the non- isothermal nematic liquid crystal system on T2, on the basis of a new approximate system which is different from the classical Ginzburg-Land...In this article, we prove the global existence of weak solutions to the non- isothermal nematic liquid crystal system on T2, on the basis of a new approximate system which is different from the classical Ginzburg-Landau approximation. Local in space energy inequalities are employed to recover the estimates on the second order spatial derivatives of the director fields locally in time, which cannot be derived from the basic energy balance. It is shown that these weak solutions satisfy the temperature equation, and also the total energy equation but away from at most finite many "singular" times, at which the energy concentration occurs and the director field losses its second order derivatives.展开更多
基金Project supported by the National Natural Science Foundation of China (No.12172001)the Anhui Provincial Natural Science Foundation of China (No.2208085Y01)+1 种基金the University Natural Science Research Project of Anhui Province of China (No.2022AH020029)the Housing and Urban-Rural Development Science and Technology Project of Anhui Province of China (No.2023-YF129)。
文摘Self-oscillating systems abound in the natural world and offer substantial potential for applications in controllers,micro-motors,medical equipments,and so on.Currently,numerical methods have been widely utilized for obtaining the characteristics of self-oscillation including amplitude and frequency.However,numerical methods are burdened by intricate computations and limited precision,hindering comprehensive investigations into self-oscillating systems.In this paper,the stability of a liquid crystal elastomer fiber self-oscillating system under a linear temperature field is studied,and analytical solutions for the amplitude and frequency are determined.Initially,we establish the governing equations of self-oscillation,elucidate two motion regimes,and reveal the underlying mechanism.Subsequently,we conduct a stability analysis and employ a multi-scale method to obtain the analytical solutions for the amplitude and frequency.The results show agreement between the multi-scale and numerical methods.This research contributes to the examination of diverse self-oscillating systems and advances the theoretical analysis of self-oscillating systems rooted in active materials.
基金partially supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202100523,KJQN202000536)the National Natural Science Foundation of China(12001074)+3 种基金the Natural Science Foundation of Chongqing(cstc2020jcyj-msxmX0606)supported by the National Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0278)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-K202100503)the Research Project of Chongqing Education Commission(CXQT21014)。
文摘In this paper,we are concerned with a three-dimensional non-isothermal model for the compressible nematic liquid crystal flows in a periodic domain.Under some smallness and structural assumptions imposed on the time-periodic force,we establish the existence of the time-periodic solutions to the system by using a regularized approximation scheme and the topological degree theory.We also prove a uniqueness result via energy estimates.
基金support by the NSFC(12071391,12231016)the Guangdong Basic and Applied Basic Research Foundation(2022A1515010860)support by the China Postdoctoral Science Foundation(2023M742401)。
文摘In this paper,we establish some regularity conditions on the density and velocity fields to guarantee the energy conservation of the weak solutions for the three-dimensional compressible nematic liquid crystal flow in the periodic domain.
基金support from the National Natural Science Foundation of China (No.62005164,62222507,62175101,and 62005166)the Shanghai Natural Science Foundation (23ZR1443700)+3 种基金Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission (23SG41)the Young Elite Scientist Sponsorship Program by CAST (No.20220042)Science and Technology Commission of Shanghai Municipality (Grant No.21DZ1100500)the Shanghai Municipal Science and Technology Major Project,and the Shanghai Frontiers Science Center Program (2021-2025 No.20).
文摘Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.
基金supports from National Natural Science Foundation of China (No.62235009).
文摘Spatial light modulators,as dynamic flat-panel optical devices,have witnessed rapid development over the past two decades,concomitant with the advancements in micro-and opto-electronic integration technology.In particular,liquid-crystal spatial light modulator(LC-SLM)technologies have been regarded as versatile tools for generating arbitrary optical fields and tailoring all degrees of freedom beyond just phase and amplitude.These devices have gained significant interest in the nascent field of structured light in space and time,facilitated by their ease of use and real-time light manipulation,fueling both fundamental research and practical applications.Here we provide an overview of the key working principles of LC-SLMs and review the significant progress made to date in their deployment for various applications,covering topics as diverse as beam shaping and steering,holography,optical trapping and tweezers,measurement,wavefront coding,optical vortex,and quantum optics.Finally,we conclude with an outlook on the potential opportunities and technical challenges in this rapidly developing field.
基金the supports from the National Natural Science Foundation of China (61905073, 61835004, 62134001, 61905031, 62105263, 62275077)Fundamental Research Fund for the Central Universities (531118010189, 310202011qd002)+1 种基金the support from Xi’an Science and Technology Association Youth Talent Support Project (095920211306)the Postdoctoral Innovation Talent Support Program of China (BX20220388)
文摘Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely applied in flat panel display industries and inspires the wavefront modulation with the development of LC alignment techniques.However,most LC elements perform only one type of optical manipulation and are difficult to realize the multifunctionality and light integration.Here,flat multifunctional liquid crystal elements(FMLCEs),merely composed of anisotropic LC molecules with space-variant orientations,are presented for multichannel information manipulation by means of polarization,space and wavelength multiplexing.Specifically,benefiting from the unique light response with the change of the incident polarization,observation plane,and working wavelength,a series of FMLCEs are demonstrated to achieve distinct near-and far-field display functions.The proposed strategy takes full advantage of basic optical parameters as the decrypted keys to improve the information capacity and security,and we expect it to find potential applications in information encryption,optical anti-counterfeiting,virtual/augmented reality,etc.
文摘We consider the Poiseuille flow of nematic liquid crystals via the full Ericksen-Leslie model.The model is described by a coupled system consisting of a heat equation and a quasilinear wave equation.In this paper,we will construct an example with a finite time cusp singularity due to the quasilinearity of the wave equation,extended from an earlier resultonaspecial case.
基金Supported by the National Natural Science Foundation of China(No.20774077)the Natural Science Foundation of Fujian Province,China(No.E0510003, E0710025)the Project of Science and Technology of Xiamen City,China(No.3502Z20055013)
文摘A series of bowlic cyclotriveratrylenes(CTV) with peripheral groups with different lengths were synthesized.These compounds were investigated by diferential scanning calorimetry and hot stage coupled polarizing microscopy.Several CTV derivatives show thermotropic liquid crystalline properties.The experimental results of their thermotropic liquid crystalline behavior indicate that the clear points,the entropy changes of melting points,the crystallization temperatures,and their entropy changes all exhibited an evident odd-even effect except the melting points,which decreased monotonously with the increase of the length of the alkoxy groups.The parameter values of CTVs with even number carbon atoms were larger than those of CTVs with odd number.When the length of alkoxyl chains was even longer,a monotonous decrease occured.Nevertheless,in the case of the entropy changes of both melting points and crystallization temperatures,the effect was valid for all the six species,and therefore,the whole curves presented as a zig-zag form.
基金supported by National Natural Science Foundation of China-NSAF: 11071043, 11131005
文摘This article is devoted to the study of the so-called incompressible limit for solutions of the compressible liquid crystals system. We consider the problem in the whole space R^N and a bounded domain of R^N with Dirichlet boundary conditions. Here we set the number of dimension N = 2 or 3.
基金This work was financially supported by the National High-Tech Research and Development Program of China (No. 2003AA327050).
文摘The planar texture of glassy cholesteric siloxane cyclic side-chain liquid crystals was fixed by quenching initially. Then the polymer network formed by the optically active polymerizable monomers imposed additional constraints on the motion of chain segments of the glassy liquid crystal and then further stabilized the molecule arrangement. A cholesteric liquid crystal film with stable optical properties was developed by this method.
基金This project was in part supported by the Hong Kong Research Grants Council(HKUST597/95P&6149/97P)
文摘A new liquid crystalline polyacetylene containing a phenyl benzoate mesogen (5) is synthesized,whose mesomorphic properties are found to be easily 'tunab1e' by simple mechanical perturbation. Thepolymerization of 10- [ 4 - (4' -methoxyphenoxycarbonyl )phenoxycarbonyl] - 1 -decyne (4 ) in itiated by theWCl_6-Ph_4Sn/dioxane complex yields polymer 5 with a M_w of 28400. The molecular structure of 5 ischaracterized by NMR, IR, and UV spectroscopy and its liquid crystalline behavior is investigated by DSC,POM, and XRD analysis. Upon mechanical perturbation, 5 exhibits unusual agitation-induced high-strengthdisclinations, shear-induced inversion walls, and solidification-induced banded textures. Such phenomenahave been observed in the main-chain liquid crystalline polymers with rigid backbones, but have seldom beenreported for the side-chain liquid crystalline polymers with flexible backbones, suggesting that the rigidpolyacetylene backbone of 5 plays a constructive role in inducing the novel molecular alignments.
基金supported by the National Natural Science Foundation of China(Grant No.61378042)the Outstanding Young Scholars Growth Plans of Colleges and Universities in Liaoning Province,China(Grant No.LJQ2013022)+1 种基金the Science and Technology Research of Liaoning Province,China(Grant No.L2010465)the Open Funds of Liaoning Province Key Laboratory of Laser and Optical Information of Shenyang Ligong University,China
文摘In this work, negative dielectric nematic liquid crystal SLC 12V620-400, chiral dopant S811, and laser dye DCM are used to prepare dye-doped chiral nematic liquid crystal laser sample. In order to investigate temperature-tunable lasing in negative dielectric chiral nematic liquid crystal, we measure the transmission and lasing spectrum of this sample. The photonic band gap (PBG) is observed to red shift with its width reducing from 71.2 nm to 40.2 nm, and its short-wavelength band edge moves 55.3 nm while the long-wavelength band edge only moves 24.9 nm. The wavelength of output laser is found to red shift from 614.4 nm at 20 ~C to 662.8 nm at 67 ~C, which is very different from the previous experimental phenomena. The refractive indices, parallel and perpendicular to the director in chiral nematic liquid crystal have different dependencies on temperature. The experiment shows that the pitch of this chiral nematic liquid crystal increases with the increase of temperature. The decrease in the PBG width, different shifts of band edges, and the red shift of laser wavelength are the results of refractive indices change and pitch thermal elongation.
基金This work was supported by the National Natural Science Foundation of China
文摘Some diacetylene-containing copolyesters with different ratios of dipropargyl 1,10-decanate anddipropargyl terephthalate were synthesized. Properties of these copolymers were characterized by differentialscanning calorimetry and polarizing optical microscopy. The copolymer could be cross-linked easily by UVirradiation in a liquid crystal matrix without adding any photoinitiator. The preliminary studies showed thatthe diacetylene-containing polymer network can assist liquid crystal molecules to align with the externalelectric field, thus reducing the response time of display devices.
文摘The synthesis and phase behaviour of chiral combined main/side chain liquid crystallinecopolymers containing pendant group constituted by chiral side group and trans-azobenzenemoiety with nitro end group are described. The formation of liquid crystalline polymorphism ofcopolymers is influenced by various contents of achiral side group.
文摘The dynamic response of molecular orientation, and the temperature and pulse shape dependences of the switching behavior in ferroelectric liquid crystal are described. The switching speed and the surface energy of ferroelectric liquid crystal are given.
基金supported by National Natural Science foundation(No.20674005)Program of National High Technology 863 program of China(No.2006AA03Z108)Science and Technology Program of Beijing,China (No.Y0405004040121)
文摘Two series of novel cholesteryl-containing H-bonded liquid crystals were prepared through facile self-assembly between cholesteryl isonicotinate (proton acceptor) exhibiting a monotropic cholesteric phase, and the 4-alkoxy-benzoic acid or 4-alkoxy cinnamic acid (proton donor). It was found that the increase of the conjugate length as well as the terminal length can contribute to enhance the interaction of molecules and thus significantly influenced the thermal behaviors of H-bonded LCs. The cholesteric reflection spectra of the induced mesogenic complexes were located in the visible region with the color tuneable thermo-sensitivity, which could be used for display application.
文摘A mechanical model of liquid crystals (LCs) is applied to study the polymorphism of homologous series of terphenyl compounds. With a senti-experimental molecular orbit method, we calculate the moment of inertia which represents the rotation state to describe the phase transition temperature obtained from experimental data. We propose a novel explanation of the phase sequence or polymorphism of LC materials using the two key parameters, the moment of inertia and critical rotational velocity. The effect of molecular polarity on the appearance of liquid crystalline is also discussed.
文摘Transition metal complexes of meso-tetra(4-myristyloxyphenyl)porphyrin TMPPM [M =Mn, Fe, Co, Ni, Cu, Zn; TMPP=mesotetra(4-myristyloxyphenyl)porphyrin] have been synthesized and characterized by means of elemental analyses, UV-Vis spectra, infrared photoacoustic spectra, 1H NMR spectra, molar conductance and differential scanning calorimetry(DSC). The ligand and the Zn complex show liquid crystalline behavior. According to the DSC thermogram of the Zn complex, it exhibits a lower phase transition temperature -7.453 ℃ and a wide mesophase temperature span, 77 ℃.
基金Hong Kong RGC Earmarked Research Grants 14305315,CUHK4041/11P and CUHK4048/13PThe Chinese University of Hong Kong,a Croucher Foundation-CAS Joint Grant,and a NSFC/RGC Joint Research Scheme(N-CUHK443/14)
文摘In this article, we prove the global existence of weak solutions to the non- isothermal nematic liquid crystal system on T2, on the basis of a new approximate system which is different from the classical Ginzburg-Landau approximation. Local in space energy inequalities are employed to recover the estimates on the second order spatial derivatives of the director fields locally in time, which cannot be derived from the basic energy balance. It is shown that these weak solutions satisfy the temperature equation, and also the total energy equation but away from at most finite many "singular" times, at which the energy concentration occurs and the director field losses its second order derivatives.