The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The blo...The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.展开更多
A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;(exce...A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;(except that with substituent of methoxy) and the clearing temperature T;of the polymers change regularly with varying of the length of the alkyl substituent groups.展开更多
Poly{2,5-bis[(p-methoxyphenyl)oxycarbonyl]styrene}was successfully synthesized.This new polymer has a structure characteristic of mesogen-jacketed liquid cyrstalline polymers(MJLCPs)and does form a liquid crystal phas...Poly{2,5-bis[(p-methoxyphenyl)oxycarbonyl]styrene}was successfully synthesized.This new polymer has a structure characteristic of mesogen-jacketed liquid cyrstalline polymers(MJLCPs)and does form a liquid crystal phase above its glass transition.It thus became the starting member of a new series of MJLCPs.The synthesis of the polymer as well as the liquid crystalline properties of the polymer and its monomer was discussed.A brief comparison of the new monomer and polymer with some previously reported counterparts was also included.展开更多
A series of 'liquid crystal polymers with two-dimensional mesogeuic units' were synthesized by the polycondensations of the monomer 2, 5-dihydroxybenzylidene-4-phenetidine with a diacid chloride selected from ...A series of 'liquid crystal polymers with two-dimensional mesogeuic units' were synthesized by the polycondensations of the monomer 2, 5-dihydroxybenzylidene-4-phenetidine with a diacid chloride selected from a series of α, ω-bis(4-chloroformylphenyloxy)carbonylalkues. This is the first series of polymers reported under the newly proposed concept 'liquid crystal polymers with two dimensional mesogenic units'.展开更多
The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The...The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.展开更多
A series of liquid crystalline polymers with T-shaped two-dimensional mesogenic unitswere synthesized via low temperature solution polycondensation of 2-(4'-alkoxy-phenyl)hydroquinone with various diacyl dichlorid...A series of liquid crystalline polymers with T-shaped two-dimensional mesogenic unitswere synthesized via low temperature solution polycondensation of 2-(4'-alkoxy-phenyl)hydroquinone with various diacyl dichlorides. The polymers were found to be nematic andshown thermotropic liquid crystalline behaviors through observations using DSC, polarizedmicroscopy and X-ray diffraction. The melting temperature T_m and the isotropizationtemperature T_i of the polymers change regularly with varying of the monomer structures.展开更多
Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers ...Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers with different diacyl dichlorides. The polymers were found to be nematic and shown liquid crystalline behavior. The melting temperature T-m and the clearing temperature T-i of the polymers change regularly with varying of the monomer structures.展开更多
A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the...A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.展开更多
The transparent solid medium of a thermotropic liquid crystal polymer have a comb structure of mesogenic side chains which exhibit a nonlinear optical response of electronic origin.The main chain of the liquid crystal...The transparent solid medium of a thermotropic liquid crystal polymer have a comb structure of mesogenic side chains which exhibit a nonlinear optical response of electronic origin.The main chain of the liquid crystal polymers can be selected from a number of suitable polymerized monomeric and comonomeric structures such as polyvinyl,polysiloxane,polyoxyalkylene, polyester etc.The electrooptic light modulator is provided,which have potential to using in the systems of laser modulation and deflection,and information control in optical circuitry etc.展开更多
Lumped element lowpass filter(LPF)for ultra-high frequency(UHF)radio frequency(RF)front-end system is presented based on multilayer liquid crystal polymer(LCP).The lumped element LPF can achieve miniaturization and on...Lumped element lowpass filter(LPF)for ultra-high frequency(UHF)radio frequency(RF)front-end system is presented based on multilayer liquid crystal polymer(LCP).The lumped element LPF can achieve miniaturization and one transmission zero on the stopband by the 8-shaped inductor.The lumped element LPF is fabricated on a 4-layer LCP substrate with a compact size of 9 mm×14 mm×0.193 mm.The measured cut off frequency of the lumped element LPF is 0.5 GHz with insertion loss(IL)less than 0.37 dB.Both measured and simulated results suggest that it is a possible candidate for the application of UHF RF front-end system.展开更多
Crosslinked liquid crystal polymers(CLCPs)are smart materials that combine the anisotropy of liquid crystals(LCs)with the elasticity of rubber.When subjected to external stimuli,they exhibit exceptional two-way shape ...Crosslinked liquid crystal polymers(CLCPs)are smart materials that combine the anisotropy of liquid crystals(LCs)with the elasticity of rubber.When subjected to external stimuli,they exhibit exceptional two-way shape memory behavior.Among the various stimuli,electrical energy has the advantages of cleanliness,stability,and high controllability;hence,it is widely used for controlling CLCP-based soft actuators,thus presenting potential for application in diverse,complex scenarios.By combining electrically driven mode and sensor equipment,precise control of CLCPs can be achieved,and the electrically driven CLCPs can accomplish more intricate and sophisticated tasks.This study presents a comprehensive review of electrically driven CLCPs with various driving mechanisms,including the electroclinic effect of ferroelectric CLCPs,the reorganization of LC molecules,the Maxwell effect of dielectric CLCPs,and the Joule heating effect of electrothermally responsive CLCP systems.In addition,a detailed analysis of the applications of electrically driven CLCPs in various research fields is presented.Finally,the current challenges in the field of electrically driven CLCP technology are summarized,along with predictions for future prospects.展开更多
Photoresponsive linear liquid crystal polymers(LLCPs)are attractive because of the excellent stimuli-responsibility and the good processability.In this study,a new photoresponsive LLCP containing azoester(PC11AE6)with...Photoresponsive linear liquid crystal polymers(LLCPs)are attractive because of the excellent stimuli-responsibility and the good processability.In this study,a new photoresponsive LLCP containing azoester(PC11AE6)with good mesophase stability was synthesized by ringopening metathesis polymerization.By introducing photoresponsive azoester mesogenic unit,which has high rigidity and a large lengthdiameter ratio,the resultant polymer possesses a broad mesophase temperature interval(isotropic temperature=180℃).A study on mesophase by 2D-wide angle X-ray diffraction indicated that the mesogens were orientated spontaneously into smectic A phase after annealing.The orientated films and fibres exhibited macroscopic,rapid and reversible deformations under light irradiation as a result of the photoisomerization of azoester as confirmed by UV-Vis absorption spectrophotometry.We anticipate that this work provides a strategy for preparing LLCP with a broad mesophase temperature range,which is positive for potential applications.展开更多
A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network(LCN) was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opa...A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network(LCN) was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties, respectively. A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN. More importantly, the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation. On the basis of this effective phototuning process, microscopic patterning of photonic film was developed under both fluorescence mode and reflection mode. The work demonstrated here provides a new route to construct photo-responsive photonic film.展开更多
Molecular mobility in thermotropic polyesters and side-chain polymers with different struc-ture of mesogens and spacers has been studied by dielectrical method in dilutesolutions. The results made it possible to estab...Molecular mobility in thermotropic polyesters and side-chain polymers with different struc-ture of mesogens and spacers has been studied by dielectrical method in dilutesolutions. The results made it possible to establish the multiplicity of dielectric relaxationtransitions which reflects the small- and large-scale types of molecular motion. It was shownthat dielectric relaxation processes occurring in accordance with local mechanism (relaxationtimes 10^(-9)--10^(-7)s. and the activation energy 10--50kJ/mol) are due to the mobility of kineticchain elements of different length within a monomer units. It was found that the dielectricrelaxation process connected with a large-scale form of molecular motion (relaxation times10^(-5)--10^(-6)s. and the activation energy 100kJ/mol) did not depend on the molecular massbut was infiuenced by factors changing the conformational state of the macromolecule. It isestablished tha the cooperative reorientation mobility of associated mesogenic fragments isthe source of the large-scale process.展开更多
Photochromic liquid crystal polymer(LCP)films can undergo spontaneous mechanical deformations upon light illuminations.The light-induced strain is due to photoisomerization and the nematic–isotropic phase transition....Photochromic liquid crystal polymer(LCP)films can undergo spontaneous mechanical deformations upon light illuminations.The light-induced strain is due to photoisomerization and the nematic–isotropic phase transition.A gradient strain exists due to absorption decay of the light intensity and will produce bending of LCP strips.Beam bending models are studied for single layered and bilayered LCP strips with substrate.The results show that the multilayered structures can have much larger bending curvature due to the utilization of the average light-induced contractions which were mostly not active for single-layered LCPs.Some structural optimizations for bilayered laminate are also discussed.展开更多
A series of poly{2,5-bis[(4-butoxyphenyl)-oxycarbonyl]styrenes}(PBPCS)with low mo-lecular weight distribution was synthesized by atom transfer radical polymerization(ATRP).The me-somorphic properties were investigated...A series of poly{2,5-bis[(4-butoxyphenyl)-oxycarbonyl]styrenes}(PBPCS)with low mo-lecular weight distribution was synthesized by atom transfer radical polymerization(ATRP).The me-somorphic properties were investigated by differential scanning calorimetry(DSC),polarizing optical microscopy(POM)and rheometer.PBPCS showed the phase transition from isotropic into liquid crystal(LC)phase,and the LC phase formed at high temperature and disappeared in the subsequent cooling procedure.Using the WAXD fiber pattern,the phase structure of the PBPCS at higher tem-perature showed hexagonal columnar nematic phase.Experimental results demonstrated that the driving force of the entropy is an important factor during the unusual LC phase formation of PBPCS.展开更多
A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris(11-acryloxyundecyloxy)- benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by et...A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris(11-acryloxyundecyloxy)- benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by etherification, acylation and finally neutralization. The chemi- cal structure was confirmed by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance spectral analysis. The self-organization behavior of the monomer with deionized water in methanol at room temperature was also demonstrated. The assemblies were char- acterized by polarized optical microscope and X-ray diffraction. The results show that a solution containing 80:20 of the monomer to water was found to be able to self-organize into Lamellar (La) phase and 92:8 with inverted hexagonal (H]I) phase, which was in ac- cordance with the theoretical calculation of critical packing parameter. It suggests that the concentration of the monomer was the key factor to influence assembly structure. Addi- tionally, the acrylate conversion with different photoinitiators and nanostructure retention after polymerization were investigated. The research shows that the acrylate conversion of the monomer with Darocur2959 could reach up to 78% when irradiated by 30 mW/cm2 UV light of 365 nm for 30 min characterized by Real-time FT-IR as well as the sol-gel method. Meanwhile, the La and HII phase nanostructures were both retained after polymerization.展开更多
In this paper, we demonstrate an alternative approach to fabricating an electrically tunable holographic polymer tem- plated blue phase liquid crystal grating. This grating is obtained by preforming a polymer template...In this paper, we demonstrate an alternative approach to fabricating an electrically tunable holographic polymer tem- plated blue phase liquid crystal grating. This grating is obtained by preforming a polymer template comprised of periodic fringes, and then refilling it with a blue phase liquid crystal. Compared with conventional holographic polymer dispersed liquid crystal gratings, our grating can remarkably reduce its switching voltage from 200 V to 43 V while maintaining a sub-millisecond response time. The holographic polymer templated blue phase liquid crystal (HPTBPLC) grating is free from electrode patterning, thus leading to a lower cost and more flexible applications.展开更多
This paper investigates the monomer kinetics of polymer dispersed liquid crystal (PDLC) grating. Fourier transform infrared (FTIR) spectra are used in the studies of photoreaction kinetics. The results indicate th...This paper investigates the monomer kinetics of polymer dispersed liquid crystal (PDLC) grating. Fourier transform infrared (FTIR) spectra are used in the studies of photoreaction kinetics. The results indicate that there is a relative stable stage arises after a very short initial stage. Based on FTIR studies, the monomer diffusion equation is deduced and necessary numerical simulations are carried out to analyse the monomer conversion which is an important point to improve phase separation structure of PDLC grating. Some simulation results have a good agreement with experimental data. In addition, the effects induced by monomer diffusion constant D and diffusion-polymerization-ratio rate R are discussed. Results show that monomer conversion can be improved by increasing value of D. Besides, a good equilibrium state (R = 1) is more beneficial to the diffusion of monomer which is important in the process of phase separation.展开更多
A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described(PLCs). Two types of PLCs of propyl hydroxypropyl cellulose ester(PPC) and octyl hydroxypropyl cellulos...A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described(PLCs). Two types of PLCs of propyl hydroxypropyl cellulose ester(PPC) and octyl hydroxypropyl cellulose ester(OPC) were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy(POM) and scanning electron microscopy(SEM), suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin(BSA) as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.展开更多
基金This project was supported by the Foundation of Peking University for Young Scientist and the National Natural Science Foundation of China.
文摘The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.
基金This work was supported by the FEYUT, SEDC, CHINA and by the National Natural Science Foundation of China.
文摘A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;(except that with substituent of methoxy) and the clearing temperature T;of the polymers change regularly with varying of the length of the alkyl substituent groups.
基金This work is supported by the National Natural Science Foundation of China.
文摘Poly{2,5-bis[(p-methoxyphenyl)oxycarbonyl]styrene}was successfully synthesized.This new polymer has a structure characteristic of mesogen-jacketed liquid cyrstalline polymers(MJLCPs)and does form a liquid crystal phase above its glass transition.It thus became the starting member of a new series of MJLCPs.The synthesis of the polymer as well as the liquid crystalline properties of the polymer and its monomer was discussed.A brief comparison of the new monomer and polymer with some previously reported counterparts was also included.
文摘A series of 'liquid crystal polymers with two-dimensional mesogeuic units' were synthesized by the polycondensations of the monomer 2, 5-dihydroxybenzylidene-4-phenetidine with a diacid chloride selected from a series of α, ω-bis(4-chloroformylphenyloxy)carbonylalkues. This is the first series of polymers reported under the newly proposed concept 'liquid crystal polymers with two dimensional mesogenic units'.
基金This work was supported by the Foundation of Peking University for Young Scientist and the National Natural Science Foundation of China(Grant No.29874003).
文摘The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.
基金This work was supported by the National Natural Science Foundation of China.
文摘A series of liquid crystalline polymers with T-shaped two-dimensional mesogenic unitswere synthesized via low temperature solution polycondensation of 2-(4'-alkoxy-phenyl)hydroquinone with various diacyl dichlorides. The polymers were found to be nematic andshown thermotropic liquid crystalline behaviors through observations using DSC, polarizedmicroscopy and X-ray diffraction. The melting temperature T_m and the isotropizationtemperature T_i of the polymers change regularly with varying of the monomer structures.
基金Tins work was supported by the National Natural Science Foundation of China.
文摘Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers with different diacyl dichlorides. The polymers were found to be nematic and shown liquid crystalline behavior. The melting temperature T-m and the clearing temperature T-i of the polymers change regularly with varying of the monomer structures.
文摘A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.
文摘The transparent solid medium of a thermotropic liquid crystal polymer have a comb structure of mesogenic side chains which exhibit a nonlinear optical response of electronic origin.The main chain of the liquid crystal polymers can be selected from a number of suitable polymerized monomeric and comonomeric structures such as polyvinyl,polysiloxane,polyoxyalkylene, polyester etc.The electrooptic light modulator is provided,which have potential to using in the systems of laser modulation and deflection,and information control in optical circuitry etc.
基金Supported by the Shaanxi Provincial Innovation Team Project(2020TD-019)the Xi'an Sciences Plan Project(21XJZZ0075)。
文摘Lumped element lowpass filter(LPF)for ultra-high frequency(UHF)radio frequency(RF)front-end system is presented based on multilayer liquid crystal polymer(LCP).The lumped element LPF can achieve miniaturization and one transmission zero on the stopband by the 8-shaped inductor.The lumped element LPF is fabricated on a 4-layer LCP substrate with a compact size of 9 mm×14 mm×0.193 mm.The measured cut off frequency of the lumped element LPF is 0.5 GHz with insertion loss(IL)less than 0.37 dB.Both measured and simulated results suggest that it is a possible candidate for the application of UHF RF front-end system.
基金The authors would like to acknowledge the financial support from the National Key Research and Development Program of China(No.2022YFA1405000)the National Natural Science Foundation of China(Nos.21971037,52173109).
文摘Crosslinked liquid crystal polymers(CLCPs)are smart materials that combine the anisotropy of liquid crystals(LCs)with the elasticity of rubber.When subjected to external stimuli,they exhibit exceptional two-way shape memory behavior.Among the various stimuli,electrical energy has the advantages of cleanliness,stability,and high controllability;hence,it is widely used for controlling CLCP-based soft actuators,thus presenting potential for application in diverse,complex scenarios.By combining electrically driven mode and sensor equipment,precise control of CLCPs can be achieved,and the electrically driven CLCPs can accomplish more intricate and sophisticated tasks.This study presents a comprehensive review of electrically driven CLCPs with various driving mechanisms,including the electroclinic effect of ferroelectric CLCPs,the reorganization of LC molecules,the Maxwell effect of dielectric CLCPs,and the Joule heating effect of electrothermally responsive CLCP systems.In addition,a detailed analysis of the applications of electrically driven CLCPs in various research fields is presented.Finally,the current challenges in the field of electrically driven CLCP technology are summarized,along with predictions for future prospects.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21734003,51573029,51721002)Natural Science Foundation of Shanghai(No.17ZR1440100)Innovation Program of Shanghai Municipal Education Commission(No.2017-01-07-00-07-E00027).
文摘Photoresponsive linear liquid crystal polymers(LLCPs)are attractive because of the excellent stimuli-responsibility and the good processability.In this study,a new photoresponsive LLCP containing azoester(PC11AE6)with good mesophase stability was synthesized by ringopening metathesis polymerization.By introducing photoresponsive azoester mesogenic unit,which has high rigidity and a large lengthdiameter ratio,the resultant polymer possesses a broad mesophase temperature interval(isotropic temperature=180℃).A study on mesophase by 2D-wide angle X-ray diffraction indicated that the mesogens were orientated spontaneously into smectic A phase after annealing.The orientated films and fibres exhibited macroscopic,rapid and reversible deformations under light irradiation as a result of the photoisomerization of azoester as confirmed by UV-Vis absorption spectrophotometry.We anticipate that this work provides a strategy for preparing LLCP with a broad mesophase temperature range,which is positive for potential applications.
基金financially supported by the National Natural Science Foundation of China (Nos. 51773009, 51573012 and 51373013)
文摘A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network(LCN) was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties, respectively. A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN. More importantly, the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation. On the basis of this effective phototuning process, microscopic patterning of photonic film was developed under both fluorescence mode and reflection mode. The work demonstrated here provides a new route to construct photo-responsive photonic film.
文摘Molecular mobility in thermotropic polyesters and side-chain polymers with different struc-ture of mesogens and spacers has been studied by dielectrical method in dilutesolutions. The results made it possible to establish the multiplicity of dielectric relaxationtransitions which reflects the small- and large-scale types of molecular motion. It was shownthat dielectric relaxation processes occurring in accordance with local mechanism (relaxationtimes 10^(-9)--10^(-7)s. and the activation energy 10--50kJ/mol) are due to the mobility of kineticchain elements of different length within a monomer units. It was found that the dielectricrelaxation process connected with a large-scale form of molecular motion (relaxation times10^(-5)--10^(-6)s. and the activation energy 100kJ/mol) did not depend on the molecular massbut was infiuenced by factors changing the conformational state of the macromolecule. It isestablished tha the cooperative reorientation mobility of associated mesogenic fragments isthe source of the large-scale process.
基金support of the National Natural Science Foundation of China(No.11072062&10772049)the High Technology Develop Program of China(863 Program:2009AA04Z408).
文摘Photochromic liquid crystal polymer(LCP)films can undergo spontaneous mechanical deformations upon light illuminations.The light-induced strain is due to photoisomerization and the nematic–isotropic phase transition.A gradient strain exists due to absorption decay of the light intensity and will produce bending of LCP strips.Beam bending models are studied for single layered and bilayered LCP strips with substrate.The results show that the multilayered structures can have much larger bending curvature due to the utilization of the average light-induced contractions which were mostly not active for single-layered LCPs.Some structural optimizations for bilayered laminate are also discussed.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20134010)the Ministry of Education of China(Key Project No.104005).
文摘A series of poly{2,5-bis[(4-butoxyphenyl)-oxycarbonyl]styrenes}(PBPCS)with low mo-lecular weight distribution was synthesized by atom transfer radical polymerization(ATRP).The me-somorphic properties were investigated by differential scanning calorimetry(DSC),polarizing optical microscopy(POM)and rheometer.PBPCS showed the phase transition from isotropic into liquid crystal(LC)phase,and the LC phase formed at high temperature and disappeared in the subsequent cooling procedure.Using the WAXD fiber pattern,the phase structure of the PBPCS at higher tem-perature showed hexagonal columnar nematic phase.Experimental results demonstrated that the driving force of the entropy is an important factor during the unusual LC phase formation of PBPCS.
文摘A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris(11-acryloxyundecyloxy)- benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by etherification, acylation and finally neutralization. The chemi- cal structure was confirmed by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance spectral analysis. The self-organization behavior of the monomer with deionized water in methanol at room temperature was also demonstrated. The assemblies were char- acterized by polarized optical microscope and X-ray diffraction. The results show that a solution containing 80:20 of the monomer to water was found to be able to self-organize into Lamellar (La) phase and 92:8 with inverted hexagonal (H]I) phase, which was in ac- cordance with the theoretical calculation of critical packing parameter. It suggests that the concentration of the monomer was the key factor to influence assembly structure. Addi- tionally, the acrylate conversion with different photoinitiators and nanostructure retention after polymerization were investigated. The research shows that the acrylate conversion of the monomer with Darocur2959 could reach up to 78% when irradiated by 30 mW/cm2 UV light of 365 nm for 30 min characterized by Real-time FT-IR as well as the sol-gel method. Meanwhile, the La and HII phase nanostructures were both retained after polymerization.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB328804)the National Natural Science Foundation of China(Grant No.61307028)+1 种基金the Funds from the Science and Technology Commission of Shanghai Municipality(Grant Nos.11JC1405300,13ZR1420000,and14ZR1422300)the Fundamental Research Funds for the Central Universities,China(Grant No.XDJK 2011C047)
文摘In this paper, we demonstrate an alternative approach to fabricating an electrically tunable holographic polymer tem- plated blue phase liquid crystal grating. This grating is obtained by preforming a polymer template comprised of periodic fringes, and then refilling it with a blue phase liquid crystal. Compared with conventional holographic polymer dispersed liquid crystal gratings, our grating can remarkably reduce its switching voltage from 200 V to 43 V while maintaining a sub-millisecond response time. The holographic polymer templated blue phase liquid crystal (HPTBPLC) grating is free from electrode patterning, thus leading to a lower cost and more flexible applications.
基金supported by Natural Science Foundation of China (Grants Nos 60578035 and 50473040)Science Foundation of Jilin Province,China (Grant Nos 20050520 and 20050321-2)
文摘This paper investigates the monomer kinetics of polymer dispersed liquid crystal (PDLC) grating. Fourier transform infrared (FTIR) spectra are used in the studies of photoreaction kinetics. The results indicate that there is a relative stable stage arises after a very short initial stage. Based on FTIR studies, the monomer diffusion equation is deduced and necessary numerical simulations are carried out to analyse the monomer conversion which is an important point to improve phase separation structure of PDLC grating. Some simulation results have a good agreement with experimental data. In addition, the effects induced by monomer diffusion constant D and diffusion-polymerization-ratio rate R are discussed. Results show that monomer conversion can be improved by increasing value of D. Besides, a good equilibrium state (R = 1) is more beneficial to the diffusion of monomer which is important in the process of phase separation.
基金Funded by the National Natural Science Foundation of China(Nos.31170911 and 31040027)the Research Development and Innovation Fund of Jinan University(No.21611410)+1 种基金the Open Fund of the First Affiliated Hospital,Jinan University,Guangzhou(No.511005024)the Macao Science and Technology Development Fund(No.064/2013/A2)
文摘A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described(PLCs). Two types of PLCs of propyl hydroxypropyl cellulose ester(PPC) and octyl hydroxypropyl cellulose ester(OPC) were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy(POM) and scanning electron microscopy(SEM), suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin(BSA) as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.