Liquid crystalline vitimers （LC-vitrimers） can be easily processed into complex three-dimensional configurations. In this paper, we present a photo-responsive LC-vitrimer by simply introducing a photo- thermal agent...Liquid crystalline vitimers （LC-vitrimers） can be easily processed into complex three-dimensional configurations. In this paper, we present a photo-responsive LC-vitrimer by simply introducing a photo- thermal agent aniline trimer into the LC-vitrimer system. As aniline trimer acts as a curing agent, it can be homogeneously dispersed in the material, avoiding aggregation which commonly happens to nano- fillers. As a result, the resultant polymer not only can perform three light-controlled functions （welding, healing and shape memory）, but also can be prepared into aligned monodomain LC actuators with strains of about 40%-45%.展开更多
Realizing both a high emission efficiency and luminescence dissymmetry factor(g_(lum))in circularly polarized solution processable organic light-emitting diodes(CP-OLEDs)remains a significant challenge.In this contrib...Realizing both a high emission efficiency and luminescence dissymmetry factor(g_(lum))in circularly polarized solution processable organic light-emitting diodes(CP-OLEDs)remains a significant challenge.In this contribution,two chiral phosphorescent liquid crystals based on cyclometalated platinum complexes are prepared,in which the chiral s-2-methyl-1-butyl group is introduced into the cyclometalating ligand and the mesogenic fragment is attached to the periphery of the ancillary ligand.The platinum complexes exhibit both smectic and chiral nematic phases as evidenced by polarized optical microscopy,differential scanning calorimetry and small-angle X-ray diffraction.Remarkably,a high photoluminescent quantum efficiency of over 78%and clear circularly polarized luminescent signal with g_(PL)of about 10^(-2)are observed for the complexes.Further,solution-processed CP-OLEDs show maximum external quantum efficiencies(EQE)of over 15%and strong circularly polarized electroluminescent signals with a g_(EL)≈10^(-2).This research demonstrates that both liquid crystallinity and the number of chiral centers play key roles in improving the chiroptical property,paving the way for a new approach for the design of high-efficiency CPL emitters.展开更多
The great potential of liquid-crystalline block copolymers(LCBCs)containing photoresponsive mesogens toward novel applications in photonics and nanotechnology has been attracting increasing attention,due to the combin...The great potential of liquid-crystalline block copolymers(LCBCs)containing photoresponsive mesogens toward novel applications in photonics and nanotechnology has been attracting increasing attention,due to the combination of the inherent property of microphase separation of block copolymers and the hierarchically-assembled structures of liquid-crystalline polymers(LCPs).The periodically ordered nanostructures in bulk film of LCBCs can be acquired by supramolecular cooperative motion,derived from the interaction between liquid-crystalline elastic deformation and microphase separation,which are able to improve physical properties of polymer film toward advanced functional applications.Moreover,various micro/nano-patterned structures have been fabricated via light manipulation of photoresponsive LCBCs with good reproducibility and mass production.Thanks to recent developments in synthesis and polymerization techniques,diverse azobenzene-containing LCBCs have been designed,resulting in the creation of a wide variety of novel functions.This review illustrates recent progresses in macroscopic regulation of hierarchical nanostructures in LCBCs towards functional materials.The existing challenges are also discussed,showing perspectives for future studies.展开更多
Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid...Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid molecules of various families (DNA and poly(I)xpoly(C)). This Au-size-dependent process is accompanied by a decrease in amplitudes of abnormal bands in the CD spectra specific to initial cholesteric liquid-crystalline dispersions and simultaneously by an appearance of plasmon resonance band in visible absorption spectrum. The study of properties of particles of cholesteric liquid-crystalline dispersion treated with Au-nanoparticles by means of various physico-chemical methods demonstrates that incorporation of Au-nanoparticles into quasinematic layers of these particles results in two effects: i) it facilitates reorganization of the spatial cholesteric structure of particles, and ii) it induces the formation of Au-clusters in the content of particles. It is not excluded that these effects represent a possible reason for genotoxicity of Au-nanopar- ticles.展开更多
A series ofpolypeptides bearing biphenyl mesogenic side-chains and oligo-ethylene-glycol （OEG） tails （PPLGn-g- BPOEGm, n = 26 and 63, m = 2, 3, and 7） has been synthesized via a 1,3-dipolar cycloaddition with quan...A series ofpolypeptides bearing biphenyl mesogenic side-chains and oligo-ethylene-glycol （OEG） tails （PPLGn-g- BPOEGm, n = 26 and 63, m = 2, 3, and 7） has been synthesized via a 1,3-dipolar cycloaddition with quantitative grafting density. FTIR results revealed that the polypeptides adopted highly stable a-helix in the temperature range of 25-200 ℃. DSC, POM and WAXS analysis revealed that PPLGn-g-BPOEGm （m ≤ 3） samples with short OEG tail length showed two main phase transitions including crystal to liquid crystalline （smectie C, SmC） phase transition and the melting transition of crystalline E-phase, while PPLG,-g-BPOEG7 with longer OEG tail length （m = 7） exhibited the melting transitions without the formation of liquid crystalline phase.展开更多
For side-chain liquid-crystalline polymers(SCLCPs)bearing calamitic mesogens,nematic and typical smectic(Sm)phases are expected.Here,using a precise polyethylene derivative with the biphenyl moiety tethered on every n...For side-chain liquid-crystalline polymers(SCLCPs)bearing calamitic mesogens,nematic and typical smectic(Sm)phases are expected.Here,using a precise polyethylene derivative with the biphenyl moiety tethered on every ninth carbon(P9,b),we demonstrated that an SCLCP could form a crystal(Cr)phase in addition to an Sm phase.Two opposing interrelations of main-and side-chains determined the molecular packings.While the side-chain inclined to be perpendicular to the main-chain in the Sm phase,they paralleled and coassembled in the Cr phase with an orthorhombic structure.The Sm phase of P9,b was new in SCLCPs.Within the mesogen sublayers,the biphenyls were tilted and had a type of two-dimensional positional order,making this Sm phase ordering higher than that of smectic C.The Sm phase was metastable and kinetically grew faster below its isotropic temperature.However,it could not convert to the stable Cr phase unless it transitioned into the melting state.Fantastically,P9,b rendered the lamellar crystal in the Cr phase.The lenticular lamellae resembled that found in linear polyethylene crystallized at low undercooling.Importantly,albeit having the large anisotropic pendants situated regularly in the backbone,P9,b could follow the principle of chain-folding crystallization.展开更多
The formation and physico-chemical properties of biomaterial, based on double-stranded (ds) DNA molecules and bearing high concentration of gadolinium, is described. This “rigid” biomaterial demonstrate a few unique...The formation and physico-chemical properties of biomaterial, based on double-stranded (ds) DNA molecules and bearing high concentration of gadolinium, is described. This “rigid” biomaterial demonstrate a few unique properties: (i) the ds DNA molecules forming complexes with gadolinium are fixed in the spatial structure of “rigid” particles, (ii) an abnormal negative band in the circular dichroism spectrum permits to follow the formation of this biomaterial;(iii) local concentration gadolinium in the content of biomaterial can reach 40%. These properties show that we are dealing with a novel type of biomaterial strongly enriched by gadolinium. This opens a gateway for practical application of this biomaterial for neutron-capture reactions. A first attempt to apply this material for neutron-capture reaction in combination with neutron generator of thermal neutron flux was performed. Positive result obtained at destruction of CHO cells allows one to state that the advantages of this biomaterial are a simple manipulation with it, a possibility to adjust its gadolinium content, long-term stability of its physico-chemical properties, as well as a reduced cost of neutron-capture experiment.展开更多
An epoxy resin based on diglycidyl ether of bisphenol A(epoxy resin E 51)was toughened with a liquid crystalline epoxy resin,4 expoxypropoxy phenyl 4′ epoxypropoxy benzoate(PHBHQ)which presented a Schlieren texture i...An epoxy resin based on diglycidyl ether of bisphenol A(epoxy resin E 51)was toughened with a liquid crystalline epoxy resin,4 expoxypropoxy phenyl 4′ epoxypropoxy benzoate(PHBHQ)which presented a Schlieren texture in the temperature range of 131～94℃ during cooling.A mixed aromatic diamine,4,4′ diaminodiphenylmethane(DDM):4,4′ diaminodiphenylsulfone(DDS):4,4′ diaminodiphenylester(DDE)=5∶2∶1 weight ratio,was used as the curing agent,and the curing conditions were adopted as 100℃/1 h,120℃/2 h,150℃/2 h and 180℃/2 h.The influence of PHBHQ on the properties of final resin systems was investigated.Compared with other toughing agents such as rubbers and thermoplastic resins,PHBHQ can improve the toughness of epoxy resin E 51 greatly without affecting the modulus and thermal resistance.The impact strength of epoxy resin E 51 modified with 50 wt% PHBHQ reached 40.2 kJ/m 2,which was higher than that of pure epoxy resin E 51 system with 23 4 kJ/m 2.The thermal property of toughing epoxy resin systems was tested with dynamic mechanical thermal analysis(DMTA).The results showed that the glass transition temperature increased about 30℃ with only 9 wt% PHBHQ.Wide angle X ray Diffraction(WAXD)was used to characterize the crystalline structure.Two diffraction angles were observed at the 9° and 23°,which showed that the nematic molecular arrangement has been kept during the crosslinking of the toughing system when the reaction was carried out in the thermal stability range of liquid crystalline phase.A two phase structure was observed on the fracture surface by scanning electronic microscopy (SEM).The oriented mesogenic domain which was dispersed in the continuous epoxy matrix can initiate,branch and terminate the cracks and endow toughening epoxy networks with excellent overall properties.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 20161300524 and 21274075)
文摘Liquid crystalline vitimers （LC-vitrimers） can be easily processed into complex three-dimensional configurations. In this paper, we present a photo-responsive LC-vitrimer by simply introducing a photo- thermal agent aniline trimer into the LC-vitrimer system. As aniline trimer acts as a curing agent, it can be homogeneously dispersed in the material, avoiding aggregation which commonly happens to nano- fillers. As a result, the resultant polymer not only can perform three light-controlled functions （welding, healing and shape memory）, but also can be prepared into aligned monodomain LC actuators with strains of about 40%-45%.
基金from the National Natural Science Foundation of China(Nos.51773021,51911530197,51473140)the Royal Society(IEC/NSFC/181139)+3 种基金the National Natural Science Foundation of China(Nos.51911530197 and 51773021)for an International Exchange Award(D.W.Bruce and Y.Wang)Six Talent Peaks Project in Jiangsu Province(No.XCL-102)Natural Science Fund for Colleges and Universities in Jiangsu Province(No.19KJA430002)Key technological tasks in Anhui Province(No.JB20007)。
文摘Realizing both a high emission efficiency and luminescence dissymmetry factor(g_(lum))in circularly polarized solution processable organic light-emitting diodes(CP-OLEDs)remains a significant challenge.In this contribution,two chiral phosphorescent liquid crystals based on cyclometalated platinum complexes are prepared,in which the chiral s-2-methyl-1-butyl group is introduced into the cyclometalating ligand and the mesogenic fragment is attached to the periphery of the ancillary ligand.The platinum complexes exhibit both smectic and chiral nematic phases as evidenced by polarized optical microscopy,differential scanning calorimetry and small-angle X-ray diffraction.Remarkably,a high photoluminescent quantum efficiency of over 78%and clear circularly polarized luminescent signal with g_(PL)of about 10^(-2)are observed for the complexes.Further,solution-processed CP-OLEDs show maximum external quantum efficiencies(EQE)of over 15%and strong circularly polarized electroluminescent signals with a g_(EL)≈10^(-2).This research demonstrates that both liquid crystallinity and the number of chiral centers play key roles in improving the chiroptical property,paving the way for a new approach for the design of high-efficiency CPL emitters.
基金supported by the National Key R&D Program of China(No.2018YFB0703702)the National Natural Science Foundation of China(Nos.51773002,51921002).
文摘The great potential of liquid-crystalline block copolymers(LCBCs)containing photoresponsive mesogens toward novel applications in photonics and nanotechnology has been attracting increasing attention,due to the combination of the inherent property of microphase separation of block copolymers and the hierarchically-assembled structures of liquid-crystalline polymers(LCPs).The periodically ordered nanostructures in bulk film of LCBCs can be acquired by supramolecular cooperative motion,derived from the interaction between liquid-crystalline elastic deformation and microphase separation,which are able to improve physical properties of polymer film toward advanced functional applications.Moreover,various micro/nano-patterned structures have been fabricated via light manipulation of photoresponsive LCBCs with good reproducibility and mass production.Thanks to recent developments in synthesis and polymerization techniques,diverse azobenzene-containing LCBCs have been designed,resulting in the creation of a wide variety of novel functions.This review illustrates recent progresses in macroscopic regulation of hierarchical nanostructures in LCBCs towards functional materials.The existing challenges are also discussed,showing perspectives for future studies.
文摘Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid molecules of various families (DNA and poly(I)xpoly(C)). This Au-size-dependent process is accompanied by a decrease in amplitudes of abnormal bands in the CD spectra specific to initial cholesteric liquid-crystalline dispersions and simultaneously by an appearance of plasmon resonance band in visible absorption spectrum. The study of properties of particles of cholesteric liquid-crystalline dispersion treated with Au-nanoparticles by means of various physico-chemical methods demonstrates that incorporation of Au-nanoparticles into quasinematic layers of these particles results in two effects: i) it facilitates reorganization of the spatial cholesteric structure of particles, and ii) it induces the formation of Au-clusters in the content of particles. It is not excluded that these effects represent a possible reason for genotoxicity of Au-nanopar- ticles.
基金financially supported by the National Natural Science Foundation of China(No.21204075)Hunan Provincial Natural Science Foundation of China(No.13JJ6042)Xiangtan University start-up fund(No.12QDZ06)
文摘A series ofpolypeptides bearing biphenyl mesogenic side-chains and oligo-ethylene-glycol （OEG） tails （PPLGn-g- BPOEGm, n = 26 and 63, m = 2, 3, and 7） has been synthesized via a 1,3-dipolar cycloaddition with quantitative grafting density. FTIR results revealed that the polypeptides adopted highly stable a-helix in the temperature range of 25-200 ℃. DSC, POM and WAXS analysis revealed that PPLGn-g-BPOEGm （m ≤ 3） samples with short OEG tail length showed two main phase transitions including crystal to liquid crystalline （smectie C, SmC） phase transition and the melting transition of crystalline E-phase, while PPLG,-g-BPOEG7 with longer OEG tail length （m = 7） exhibited the melting transitions without the formation of liquid crystalline phase.
基金supported by the National Natural Science Foundation of China(grant nos.21634001,21875157,and 51921002)the National Key R&D Program of China(no.2018YFB0703703)The TEM facility is made available by Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices(nos.2019B121203003 and 2016ZT06C322).
文摘For side-chain liquid-crystalline polymers(SCLCPs)bearing calamitic mesogens,nematic and typical smectic(Sm)phases are expected.Here,using a precise polyethylene derivative with the biphenyl moiety tethered on every ninth carbon(P9,b),we demonstrated that an SCLCP could form a crystal(Cr)phase in addition to an Sm phase.Two opposing interrelations of main-and side-chains determined the molecular packings.While the side-chain inclined to be perpendicular to the main-chain in the Sm phase,they paralleled and coassembled in the Cr phase with an orthorhombic structure.The Sm phase of P9,b was new in SCLCPs.Within the mesogen sublayers,the biphenyls were tilted and had a type of two-dimensional positional order,making this Sm phase ordering higher than that of smectic C.The Sm phase was metastable and kinetically grew faster below its isotropic temperature.However,it could not convert to the stable Cr phase unless it transitioned into the melting state.Fantastically,P9,b rendered the lamellar crystal in the Cr phase.The lenticular lamellae resembled that found in linear polyethylene crystallized at low undercooling.Importantly,albeit having the large anisotropic pendants situated regularly in the backbone,P9,b could follow the principle of chain-folding crystallization.
文摘The formation and physico-chemical properties of biomaterial, based on double-stranded (ds) DNA molecules and bearing high concentration of gadolinium, is described. This “rigid” biomaterial demonstrate a few unique properties: (i) the ds DNA molecules forming complexes with gadolinium are fixed in the spatial structure of “rigid” particles, (ii) an abnormal negative band in the circular dichroism spectrum permits to follow the formation of this biomaterial;(iii) local concentration gadolinium in the content of biomaterial can reach 40%. These properties show that we are dealing with a novel type of biomaterial strongly enriched by gadolinium. This opens a gateway for practical application of this biomaterial for neutron-capture reactions. A first attempt to apply this material for neutron-capture reaction in combination with neutron generator of thermal neutron flux was performed. Positive result obtained at destruction of CHO cells allows one to state that the advantages of this biomaterial are a simple manipulation with it, a possibility to adjust its gadolinium content, long-term stability of its physico-chemical properties, as well as a reduced cost of neutron-capture experiment.
文摘An epoxy resin based on diglycidyl ether of bisphenol A(epoxy resin E 51)was toughened with a liquid crystalline epoxy resin,4 expoxypropoxy phenyl 4′ epoxypropoxy benzoate(PHBHQ)which presented a Schlieren texture in the temperature range of 131～94℃ during cooling.A mixed aromatic diamine,4,4′ diaminodiphenylmethane(DDM):4,4′ diaminodiphenylsulfone(DDS):4,4′ diaminodiphenylester(DDE)=5∶2∶1 weight ratio,was used as the curing agent,and the curing conditions were adopted as 100℃/1 h,120℃/2 h,150℃/2 h and 180℃/2 h.The influence of PHBHQ on the properties of final resin systems was investigated.Compared with other toughing agents such as rubbers and thermoplastic resins,PHBHQ can improve the toughness of epoxy resin E 51 greatly without affecting the modulus and thermal resistance.The impact strength of epoxy resin E 51 modified with 50 wt% PHBHQ reached 40.2 kJ/m 2,which was higher than that of pure epoxy resin E 51 system with 23 4 kJ/m 2.The thermal property of toughing epoxy resin systems was tested with dynamic mechanical thermal analysis(DMTA).The results showed that the glass transition temperature increased about 30℃ with only 9 wt% PHBHQ.Wide angle X ray Diffraction(WAXD)was used to characterize the crystalline structure.Two diffraction angles were observed at the 9° and 23°,which showed that the nematic molecular arrangement has been kept during the crosslinking of the toughing system when the reaction was carried out in the thermal stability range of liquid crystalline phase.A two phase structure was observed on the fracture surface by scanning electronic microscopy (SEM).The oriented mesogenic domain which was dispersed in the continuous epoxy matrix can initiate,branch and terminate the cracks and endow toughening epoxy networks with excellent overall properties.
