含酒石酸基元的液晶单体及其聚合物的合成与表征

合成了一种以酒石酸为中心的新型工字型液晶单体2,3-二乙酰氧基-1,4-丁二酸对烯丙氧基苯甲酸对苯二酚酯(M1),将其与手性液晶单体4-烯丙氧基苯甲酸胆甾醇酯(M2)共聚,得到侧链液晶聚合物P1～P8。通过红外光谱(FT-IR)、核磁共振(1H-NMR)、偏光显微镜(POM)、差示扫描量热分析(DSC)和X射线衍射(XRD)等手段对所获单体及聚合物的结构和液晶相行为进行了表征。结果表明,液晶单体M1具有近晶相扇形、纹影织构,手性单体M2具有胆甾相油丝织构。聚合物P1～P8出现胆甾相的Grandjean织构,随着单体M1含量的增加,聚合物P1～P8的Tg呈上升趋势,液晶区间变窄。     

含手性基元的侧链液晶聚合物的合成与性能表征

文中设计与合成了国内未见报道的单体M1、M2和系列手性液晶聚合物。通过差示扫描量热(DSC)、偏光显微分析(POM)、广角X射线衍射、旋光仪等测试手段研究了单体M1和手性液晶聚合物液晶性能。结果表明,M1为向列型液晶单体,M2为手性非液晶单体。聚合物P2~P4呈现近晶A相,P5,P6为胆甾相,P7的液晶性能已不明显,聚合物P8已没有液晶性能。具有宽的液晶相范围,液晶相范围均高于140℃。随着手性单体M2含量(0%~50%)的增加,聚合物的玻璃化转变温度、清亮点温度、液晶相范围均呈现降低趋势。     

聚硅氧烷类手性偶氮液晶高分子的制备

合成了一种含胆甾醇基元的手性液晶单体4-烯丙氧基苯甲酰氧基异丙酰氧基胆甾基酯(M)和一种含偶氮基元的液晶单体4-烯丙氧基苯甲酰氧基异丙酰氧基偶氮苯甲酸乙酯(N),将它们与含氢聚硅氧烷接枝共聚,得到侧链手性偶氮液晶聚合物PA1~PA6。通过红外、核磁共振、旋光仪、偏光显微镜、差示扫描量热和X射线衍射等手段对所合成单体及聚合物的结构和液晶相行为进行了表征。结果表明,单体M具有胆甾相的油丝织构,单体N具有向列相的纹影织构,聚合物PA1~PA6呈现胆甾相的Grandjean织构,它们的热稳定性好,液晶区间宽达171~180℃之间。     

含异山梨醇基元的液晶单体及其聚合物的研究

以异山梨醇为手性剂合成了新型手性液晶单体2-(10-十一烯酸)-5-(4-乙氧基苯甲酰氧基联苯)氧羰基甲酸异山梨醇酯(M1)和2-(10-十一烯酸)-5-(4-乙氧基苯甲酰氧基联苯)氧羰基戊酸异山梨醇酯(M2),及对应的液晶聚合物P1和P2。所获得的单体及聚合物的结构与液晶性能通过了FT-IR1、H-NM R、POM、DSC和XRD的表征。研究表明,液晶单体M1和M2呈现胆甾相的油丝织构、指纹织构和焦锥织构,聚合物P1和P2呈现近晶A相的扇形织构。此外,所获得的聚合物具有宽的液晶相温度范围和高的热稳定性。     

基于L-丙氨酸的手性聚酰胺酰亚胺的合成与表征

通过L-丙氨酸与均苯四甲酸二酐的缩合反应得到手性酰亚胺,再与二苯基甲烷二异氰酸酯（MDI）聚合制备出基于L-丙氨酸的手性聚酰胺酰亚胺。用傅立叶红外光谱仪（FT-IR）,核磁共振（1H-NMR）表征了聚合物的结构。用差示扫描量热法（DSC）和热重分析（TG）研究了共聚物的结晶性能和热稳定性,同时对聚合物的溶解性能进行了探...     

N-炔丙基酰胺共聚物组成对其光学活性的影响

通过与手性单体共聚,可调控基于非手性单体所制备的螺旋聚合物的光学活性。文中利用[Rh]金属有机催化剂,进行了手性(M1)和非手性(M2)N-炔丙基酰胺单体的共聚反应,聚合物产率高于97%。利用圆二色光谱技术及旋光仪对共聚物的光学活性进行了表征,发现共聚物组成对其光学活性有显著影响,不仅影响共聚物光学活性的大小,甚至还决定着聚合物主链所形成螺旋结构的手性。     

光学活性甲基丙烯酰胺类聚合物的合成及其性能研究

利用两步反应合成新的手性烯类单体N-(S)-(苯甘氨酸乙酯)甲基丙烯酰胺(S-OCB)。通过可逆加成-断裂链转移自由基聚合(RAFT),新型手性单体S-OCB和甲基丙烯酸甲酯(MMA)在不同条件获得具有不同性质的二嵌锻聚合物,且用IR、GPC和DSC来表征聚合物的具体性质。结果表明聚合物的数均分子量和单体SOCB的浓度呈线性关系,通过GPC曲线得出聚合物具有较小的分子量分布。以聚合物P2、P3和P5制备了涂敷型高效液相色谱用手性固定相CSP-2、CSP-3和CSP-5,结果表明该类固定相对三(乙酰丙酮)钴具有显著的手性识别能力。     

含氟与胆甾醇基液晶聚合物的合成与表征

将一种含胆甾醇基液晶单体、一种含氟单体与聚甲基含氢硅氧烷接枝共聚合成了一系列液晶聚合物。采用红外光谱(FT-IR)、核磁共振(1H-NMR)、偏光显微镜(POM)、X射线衍射(WXRD)与差示扫描量热分析(DSC)等测试手段,对单体及聚合物进行了结构与性能的表征。随着含氟基团组分含量逐渐增加,该系列液晶聚合物的玻璃化转变温度与清亮点都呈现降低趋势,并且液晶相由胆甾相转变为近晶相。由于含氟部分和聚合物中的碳氢部分极难相容,形成层状聚集,从而使胆甾相受到抑制,有利于近晶相的形成和稳定。     

一种具有光学活性的手性侧链液晶聚合物的合成与性能

介晶单体十一烯酸胆甾醇酯(M1)和手性单体丙烯酸薄荷醇酯(M2)通过接枝共聚引入聚甲基含氢硅氧烷(PMHS)中，制得系列侧链聚合物P1～P8。通过DSC、偏光显微镜(POM)、X射线衍射分析(WAXD，SAXS)、旋光仪等手段对聚合物进行了表征。聚合物P1～P8都具有光学活性，均为胆甾型热致液晶，具有较宽的介晶相范围，呈现出清晰的彩色Grand—jean织构及油丝织构。但当M2含量大于30％时，聚合物的液晶性能逐渐变弱。     

手性二糖对主链液晶聚合物性能的影响

采用溶液缩聚的方法,以6,6′-二羟基麦芽糖六乙酸酯(MA)、4,4′-对羟基联苯酚(MB)、癸二酰氯(SD)为单体,合成了主链液晶聚合物(P1～P7)。通过红外光谱(FT-IR),核磁共振谱(1H-NMR)、偏光显微分析(POM)、旋光性分析(SROT)、差示扫描量热(DSC)、X射线分析(XRD)等手段研究了手性单体对主链液晶聚合物性能的影响。研究表明,P1～P5呈现出近晶相的破碎焦锥织构,P6～P7呈现出胆甾相的彩色平面织构,手性基元的引入诱导出了胆甾相。液晶聚合物的玻璃化转变温度(Tg),熔点(Tm)和清亮点(Ti)随手性单体含量的增加而降低。     

Synthesis and characterization of novel liquid crystalline polymers containing cholesteryl pendant groups

In order to investigate the chiral effect of cholesteryl pendant groups on the induction of the cholesteric phase, a new cholesteryl-containing liquid crystalline monomer was synthesized and copolymerized with an achiral comonomer in various molar ratios. The layer-like arrangement of the smectic mesophase with different monomeric compositions of copolymers was investigated using an X-ray diffraction analysis. The cholesteric liquid phase was induced by the chiral segments; the dependence of the reciprocal central reflection wavelength on the mole fraction of the chiral monomer for copolymers was investigated. This paper demonstrates the effect of chiral pendant groups on the induction of the cholesteric phase and layered molecular arrangement of side-chain liquid crystalline polymers.     

用原子转移自由基聚合方法合成胆甾侧链液晶聚合物

以胆固醇氯甲酸酯和丙烯酸羟乙酯为原料。合成了丙烯酸羟乙酯基胆甾醇碳酸酯(简称GMCC),作为一种含液晶基元的单体,使之在苯甲醚溶液中在Ebib／CuBr／MA3-DETA催化系统下进行原子转移自由基聚合(ATRP)．动力学分析表明。转化率随着反应时间呈线性增加,Ln[M]0／[M]与反应时间呈良好线性关系。反应产物的分子量分布较窄(1．3左右)．所得产物可作为大引发剂引发丙烯酸甲(丁)酯通过同样的催化体系．进一步聚合成嵌段共聚物．胆甾侧链液晶聚合物的相转变温度和织构偏光显微镜观察表明,这种聚合物具有良好的液晶性能．     

Synthesis and characterization of chiral liquid crystal polymers containing donor–acceptor group

A series of new chiral side-chain liquid crystalline polymers with electron donor–acceptor action were prepared containing chiral monomer with donor group and nematic LC monomer with acceptor group. All polymers were synthesized by graft polymerization using polymethylhydrosiloxane as backbone. The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), thermogravimetric analyses (TGA), and X-ray diffraction measurements (XRD). The chemical structures of monomers and polymers were confirmed by Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra (¹H NMR and ¹³CNMR). M ₁ did not show liquid crystalline phase and M ₂ turned out nematic phase on heating and cooling cycle. Polymers P ₂ –P ₇ were cholesteric phase. Cholesteric phase and low glass temperature liquid crystalline polymers have been obtained, which offered the possibility of application. Experimental results demonstrated that the glass-transition temperatures rose and isotropization temperatures decreased and the ranges of the mesophase temperature reduced with increasing the content of chiral agent. All of the obtained polymers showed high thermal stability.     

液晶型成核剂的合成及对聚乙烯结晶行为的影响--(Ⅰ)液晶型成核剂的合成与表征

以对羟基苯甲酸、对羟基苯甲醚和丙烯酰氯为主要原料,通过逐步酰化反应,合成出了一种具有刚性结构并带有极性基团的乙烯基单体：4-(4-甲氧基)-二酚氧羰基酚丙烯酸酯(ACDHP),并通过自由基引发合成出相应的聚合物PACDHP。利用^1H-NMR和FT-IR对单体和聚合物的化学结构进行了表征。采用DSC、热台偏光显微镜(HS-POM)和TGA对聚合物的相转变温度、液晶态的织构和热稳定性进行了研究。结果表明该热致液晶聚合物的液晶相变温度范围较宽,热稳定性较好．     

Polymer Network–Stabilized Liquid Crystals

The fabrication and properties of polymer network–stabilized liquid crystals, formed by polymerization of a small amount of a bifunctional photoreactive monomer dissolved in a liquid‐crystalline phase, are reviewed. The polymer network morphology is strongly related to preparation conditions such as monomer content, polymerization temperature, and ultraviolet (UV) curing conditions. The transfer of anisotropic liquid‐crystalline order onto the network is discussed in detail. The electro‐optical performance of network‐stabilized nematics, cholesterics, and ferroelectric smectics is largely dependent on the morphology of the network, as will be demonstrated with an emphasis laid on polymer‐stabilized cholesteric textures (PSCTs). A general correlation between polymerization conditions, network morphology, and electro‐optical behavior will be outlined and aspects concerning applications discussed.     

Liquid crystalline elastomers based on cyclic cyclosiloxane and mesogenic crosslinking units

Cholesteric liquid crystalline elastomers (LCEs) IP–VIP were graft copolymerized by a one-step hydrosilylation reaction with cyclo(pentamethylhydrogeno)siloxane, a cholesteric liquid crystalline (LC) monomer cholesteryl 3-(4-(undec-10-enoyloxy)phenyl)acrylate and crosslinking LC monomer biphenyl-4,4′-diyl bis(4-(allyloxy)benzoate). The effect of crosslinking mesogens on mesomorphic properties of the chiral LCEs was studied by swelling experiments. All the samples IP–VIP showed cholesteric mesophase when they were heated and cooled. The glass transition temperature (T _g) of elastomers increased slightly with increase of crosslinking mesogens in the polymer systems, but mesophase–isotropic phase transition temperature (T _i) decreased slightly, suggesting that the temperature range of mesophase became narrow with increase of crosslinking mesogens for all the elastomers. In XRD curves, all the samples IP–VIP exhibited diffuse reflections at 2θ ≈ 17° suggesting lack of the smectic-layered packing arrangement, and the intensity of these diffuse diffraction peaks decreases with increase of mesogenic crosslinking units, suggesting that the order between two neighbor LC molecules disturbed by the mesogenic crosslinking agents. The maximum reflection bands shift slightly to long wavelength and become broad at the same temperature, indicating that the helical structure is partially disrupted because of both the constraint of chemical crosslinking agents and the different mesogenic units.     

Dual Light and Temperature Responsive Micrometer‐Sized Structural Color Actuators

Externally induced color‐ and shape‐changes in micrometer‐sized objects are of great interest in novel application fields such as optofluidics and microrobotics. In this work, light and temperature responsive micrometer‐sized structural color actuators based on cholesteric liquid‐crystalline (CLC) polymer particles are presented. The particles are synthesized by suspension polymerization using a reactive CLC monomer mixture having a light responsive azobenzene dye. The particles exhibit anisotropic spot‐like and arc‐like reflective colored domains ranging from red to blue. Electron microscopy reveals a multidirectional asymmetric arrangement of the cholesteric layers in the particles and numerical simulations elucidate the anisotropic optical properties. Upon light exposure, the particles show reversible asymmetric shape deformations combined with structural color changes. When the temperature is increased above the liquid crystal‐isotropic phase transition temperature of the particles, the deformation is followed by a reduction or disappearance of the reflection. Such dual light and temperature responsive structural color actuators are interesting for a variety of micrometer‐sized devices.     

New chiral liquid crystalline monomers, polymers, and elastomers derived from menthol derivatives: synthesis and mesomorphism

To investigate liquid crystalline properties and structure relationships of chiral compounds based on menthol, a series of new chiral monomers derived from menthol derivatives, a mesogenic crosslinking agent, the corresponding side chain homopolymers with siloxane backbone, and cholesteric elastomers were synthesized. The structures and purity of these chiral compounds obtained in this study were characterized using FTIR, ¹H NMR, and elemental analyses. The mesomorphism and thermal stabilities were investigated using differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analysis, and X-ray diffraction. The selective reflection of light for the chiral monomers was studied with UV/visible/near IR. The effect of the crosslinking agent content on the phase transition temperatures of the elastomers was discussed. It was found that these chiral monomers seemed beneficial for the formation of the mesophases when a flexible spacer was inserted between the mesogenic core and the terminal menthyl groups. All obtained chiral monomers showed a cholesteric phase, chiral smectic C phase, and cubic blue phase. The crosslinking agent exhibited a smectic A (S_A) phase and nematic phase. However, their corresponding homopolymers with siloxane chains tended to form a lower order S_A phase. With an increase of the mesogenic rigidity, the melting temperatures, glass transition temperatures (T _g), and isotropic temperatures (T _i) of chiral monomers or homopolymers all increased. For the elastomers, general tendency was toward increased T _g and T _i with increasing the crosslinking agent content.     

向列型热致液晶聚酰胺的结构表征

采用傅立叶红外光谱仪（IR）、广角X射线衍射仪（WAXD）、热台偏光显微镜（POM）及扫描电子显微镜（SEM）对所合成热致液晶聚酰胺进行了结构表征。IR谱图显示了该聚合物为半刚性结构,与所设计的分子结构相一致;WAXD曲线显示处于液晶态的聚合物在2θ=20°左右有一弥散的峰,表明该液晶聚合物为向列型液晶结构;POM观察...