氢键组装PVA侧链液晶高分子材料的合成

以异烟酸、对硝基苯酚为主要原料首先合成了一种介晶基元异烟酸对硝基苯酚酯,然后以聚乙烯醇(PVA)分子的羟基氢为电子受体,异烟酸对硝基苯酚酯分子中的氮原子为电子供体,通过氢键自组装制备了氢键组装PVA侧链液晶高分子.用IR和1HNMR对介晶基元异烟酸对硝基苯酚酯和氢键组装PVA侧链液晶高分子的结构进行了表征,用DSC和热台偏光显微镜(POM)对它们的液晶行为进行了分析.结果表明,所合成的异烟酸对硝基苯酚酯和氢键组装PVA侧链液晶高分子均显示出热致液晶性能.     

聚乙烯醇侧链液晶高分子的合成与表征

合成了聚乙烯醇侧链液晶高分子并对其进行表征.利用聚乙烯醇中羟基的给质子能力和苯乙烯吡啶上氮原子的授质子能力形成的氢键,通过分子自组装合成聚乙烯醇侧链液晶高分子.这是一种热致性向列型液晶高分子.由于聚乙烯醇主链良好的柔顺性,该侧链液晶高分子具有较低的相转变温度和较宽的液晶温度范围.同时,通过氢键连接液晶基元和聚合物主链,相对减弱了液晶基元与聚合物之间的相互作用力,使它们之间保留了一定的自由性,提高了侧链液晶高分子的柔顺性,扩大了其使用范围。     

一类聚乙烯吡啶氢键侧链高分子的合成与液晶性能

以聚乙烯吡啶为氢键受体,以Schiff碱型羧酸衍生物为氢键给体合成了一类新型侧链氢键液晶高分子。通过红外光谱和核磁氢谱对化合物的结构进行了表征;产物与氢键给体的红外光谱的对比确定了分子间氢键的存在,通过带热台的偏光显微镜(POM)对化合物的液晶相变温度和液晶相的形态进行了测试。结果表明:随着碳链长度的增加,此类侧链氢键液晶高分子液晶相的清亮点温度呈现先降低后升高的趋势;并且液晶相呈现了新型的织构。     

液晶分子在受限条件下的液晶相行为（Ⅱ）某些化学受限环境对液晶相行为的影响

综述了液晶分子在与聚合物嵌段、碳纳米管（CNT）和多面低聚倍半硅氧烷（POSS）等通过共价键形成的化学受限环境下的液晶相行为。聚合物嵌段微区的受限作用使侧链液晶嵌段共聚物的液晶有序度减小,相变温度降低。由于碳纳米管的受限作用,液晶聚合物接枝CNTs的有序结构被破坏,液晶性丧失。POSS以共价键的方式引入到液晶分子中,明显提高了液晶相的稳定性。但是当POSS含量高于某临界值后使液晶分子表现出单向性液晶相行为,甚至使其丧失液晶性。     

两种新型氢键诱导液晶材料的合成及表征

以对氨基苯甲酸、对硝基苯甲醛和吡啶衍生物为原料合成了两种新型氢键诱导液晶。用IR、1H-NMR和元素分析对所合成的化合物进行了结构表征,并用DSC和带热台的偏光显微镜分别对质子供体和超分子复合物复合前后的液晶行为进行了研究。结果表明:合成了目标化合物;IR结果证明了羧基和吡啶环间分子间氢键代替了羧基间的分子间氢键,复合物表现出分子的热力学行为;液晶行为研究证明了氢键复合物是典型的热致液晶且呈现明显的向列型液晶态,超分子液晶复合物较质子供体的液晶相范围宽且其相转变温度低于质子供体,说明分子间氢键起到了稳定液晶相态的作用。     

羧酸吡啶类氢键液晶分子的合成及表征

以4-己氧基苯甲酸为质子给体,4-硝基苯乙烯基吡啶为受体,四氢呋喃为溶剂,制备了一种液晶超分子复合物—羧酸吡啶类氢键自主装型液晶复合物,用DSC和热台偏光显微镜对所合成化合物进行了相态和液晶性研究,并用IR1、H-NMR对所合成化合物进行了结构表征。结果表明:合成了目标化合物;IR结果证明了羧基和吡啶环间分子间氢键代替了羧基间的分子间氢键;相态及液晶行为研究证明了氢键复合物具有典型的热致液晶性能且呈现明显的向列型液晶态。     

稳定蓝相液晶的研究进展

介绍了蓝相液晶特殊的“双轴螺旋”结构,并解释了其三维晶格的形成.阐述了蓝相液晶在显示器件中的应用优势和原理.分类详细介绍了诸如聚合物稳定、纳米粒子稳定、“香蕉”型或“T”型分子诱发稳定、双液晶基元以及氢键稳定等拓宽蓝相温度范围的方法,分析了各自的特点和优势.最后对蓝相液晶的应用前景进行了展望.     

改性还原染料分子自组装性的研究

利用偏光显微镜、摩尔电导率和紫外-可见光光谱研究了改性还原染料如还原蓝RSN、还原猩红GG和还原深蓝BO的自组装性能,考察了浓度、温度及染料混合对其分子自组装性能的影响,分析磺化还原染料分子自组装聚集体的类型及其形成机理,结果表明分子依靠芳环间π-π共轭作用、磺酸基和溶剂水之间氢键作用力,自组装为有序结构的聚集体.磺化还原蓝RSN、磺化还原深蓝BO水溶液分子自组装为H聚集体,磺化还原猩红GG形成J聚集体.分子结构和引入亲水基影响其自组装方式和类型,一定浓度下分子自组装形成溶致液晶相,正交偏振光下,织构呈丝状、条状和粒状分布,磺化还原染料混合组装的均匀性与其浓度直接相关.     

大分子自组装及其应用的研究与进展

综述了化学吸附、分子沉积、旋涂、慢蒸发溶剂和枝接成膜等 5种大分子自组装成膜方法 ,并介绍了其在液晶、非线性光学材料、聚合物表面改性等材料领域的应用及其表征研究。     

新型希夫碱型液晶超分子化合物的合成和表征

通过醚化、还原、缩合及酯化等反应,合成了以4-[((4-己烷氧苯基)亚氨基)甲基]苯基异烟酸酯为质子受体,烷氧基苯甲酸为质子供体,氢键为链接基的希夫碱型超分子液晶化合物。用IR、1H NMR对中间体及其产物进行了结构表征,并用热台偏光显微镜分别对目标产物的液晶行为进行了研究。通过IR对羧基和吡啶环间分子间氢键的形成进行了验证,通过偏光显微镜说明氢键复合物是典型的热致液晶且呈现近晶相和向列相两种相态,并且复合物较质子供体和受体的液晶相范围宽,说明分子间氢键起到了稳定液晶相态的作用。     

侧链液晶聚乙炔的合成及性能表征

取向液晶侧链引入聚乙炔主链促使主链共轭性提高,导致获得电活性和取向性的永久结合。最近,已有不少研究组将聚炔共轭聚合物作为刚性主链应用于制备侧链液晶聚合物。文中主要阐述带有液晶侧链聚乙炔的合成、液晶性及光学性能,并根据侧链液晶基元结构对其进行分类。     

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.     

Controlling the morphology of side chain liquid crystalline block copolymer thin films through variations in liquid crystalline content

In this paper, we describe methods for manipulating the morphology of side-chain liquid crystalline block copolymers through variations in the liquid crystalline content. By systematically controlling the covalent attachment of side chain liquid crystals to a block copolymer (BCP) backbone, the morphology of both the liquid crystalline (LC) mesophase and the phase-segregated BCP microstructures can be precisely manipulated. Increases in LC functionalization lead to stronger preferences for the anchoring of the LC mesophase relative to the substrate and the intermaterial dividing surface. By manipulating the strength of these interactions, the arrangement and ordering of the ultrathin film block copolymer nanostructures can be controlled, yielding a range of morphologies that includes perpendicular and parallel cylinders, as well as both perpendicular and parallel lamellae. Additionally, we demonstrate the utilization of selective etching to create a nanoporous liquid crystalline polymer thin film. The unique control over the orientation and order of the self-assembled morphologies with respect to the substrate will allow for the custom design of thin films for specific nanopatterning applications without manipulation of the surface chemistry or the application of external fields.     

A glance at the relation of stepwise coupling polymerization to supramolecular chemistry

A relationship between supramolecular chemistry and stepwise coupling polymerization (SCP) found by our group is briefly described. By SCP reaction a series of new kinds of microstructure-controlled polymers and their corresponding supramolecular inclusions such as: (1) reactive ladder-like polysiloxanes (LPS); (2) liquid crystalline ladder-like polysiloxanes and their metal complexes including fishbone-like LCPs (FBLCPs) and their metal complexes (M-FBLCPs) and rowboat-like LCPs (RBLCPs); (3) tubular polymers (TPs) and their supramolecular inclusions (TPIs) and (4) sieve-plate-like network polymers (SNPs) and their supramolecular clathrates (SNPC) have been successfully prepared. It is reasonably stated that SCP is a supramolecular interaction-aided reaction and moreover, SCP is an effective method to generate new supramolecules.     

含不同离子的液晶离聚物对PBT/PP共混物的形态结构和力学性能的影响

合成了三种含有不同离子的液晶离聚物:含磺酸离子的液晶离聚物(LCI-S),含铵离子的液晶离聚物(LCI-N)和含有羧酸离子的液晶离聚物(LCI-C),将三种液晶离聚物分别与聚对苯二甲酸丁二醇酯(PBT)和聚丙烯(PP)熔融共混。将合成的共混物通过三维红外图象系统和拉伸试验方法进行了微观形态和力学性能的分析。比较不同离子对共混物相容性的影响。结果表明,由于磺酸离子的极性铵离子羧酸离子,因此LCI-S对共混物的增容作用LCI-NLCI-C。     

热致可逆变色胆甾液晶聚合物的制备和光学性能研究

合成了两种胆甾液晶单体,4-烯丙氧基苯甲酸胆甾醇酯M1和4-{4-[(4-烯丙氧基)-苯甲酰氧基]丁氧羰基}苯甲酸胆甾醇酯M2。将两种单体按一定比例与含氢聚硅氧烷(PMHS)共聚得到了一系列侧链液晶聚合物P1-P6。采用红外光谱(FT-IR)、核磁共振(1 H NMR)、差示扫描量热(DSC)、偏光显微镜(POM)和X射线等手段对单体及聚合物的结构、液晶性能和相行为进行了表征。通过分析表明单体M1、M2和聚合物为热致胆甾型液晶,聚合物在常温具有选择性反射现象,在升温—降温—再升温的过程中反射波长随温度升高发生蓝移,且聚合物具有良好的热稳定性和可逆变色性。     

All-hydrocarbon liquid crystalline polysiloxane polymer as stationary phase in gas chromatography capillary column for separation of isomeric compounds of polynuclear aromatic hydrocarbons

Two new and high-purity all-hydrocarbon side-chain liquid crystalline polysiloxane polymers were synthesized by grafting all-hydrocarbon liquid crystal monomers onto a polymethylhydrosiloxane backbone. The two polysiloxane polymers show both smectic B and E mesophases which were characterized by (differential scanning calorimetry and X-ray analysis. As stationary phases, these liquid crystalline polysiloxane polymers were coated on the inner surface of a capillary column (i.d. = 0.32 mm, film thickness d(f) ≈ 0.25 μm) using the static coating method. The capillary column was installed on a GC/MS instrument. We used a standard commercial mixture of 21 species of polynuclear aromatic hydrocarbons (purchased from Supelco Co. and Merck Co.) to test the chromatographic behavior of the coated stationary phase. Test results of the isomeric pair compounds show a better separation resolution than identical tests using the commercial HP-5 capillary column, which is a standard and state-of-the-art analytical tool for the chromatographic resolution of PAHs.     

Inside Front Cover: Macroscopic Parallel Nanocylinder Array Fabrication Using a Simple Rubbing Technique (Adv. Mater. 17/2006)

A simple rubbing technique to macroscopically align nanocylinders in an amphiphilic diblock liquid‐crystalline copolymer is reported by Ikeda and co‐workers on p. 2213. The inside cover shows highly ordered arrays of nanocylinders parallel to the rubbing direction owing to supramolecular cooperative motions between mesogens and microphase‐separated domains. This opens a novel, convenient pathway for controlling defect‐free nanoscopic domains over large areas.     

From Supramolecular Organic Cages to Porous Covalent Organic Frameworks for Enhancing Iodine Adsorption Capability by Fully Exposed Nitrogen-Rich Sites

In order to overcome the limitations of supramolecular organic cages for their incomplete accessibility of active sites in the solid state and uneasy recyclability in liquid solution, herein a nitrogen-rich organic cage is rationally linked into framework systems and four isoreticular covalent organic frameworks (COFs), that is, Cage-TFB-COF, Cage-NTBA-COF, Cage-TFPB-COF, and Cage-TFPT-COF, are successfully synthesized. Structure determination reveals that they are all high-quality crystalline materials derived from the eclipsed packing of related isoreticular two-dimensional frameworks. Since the nitrogen-rich sites usually have a high affinity toward iodine species, iodine adsorption investigations are carried out and the results show that all of them display an enhancement in iodine adsorption capacities. Especially, Cage-NTBA-COF exhibits an iodine adsorption capacity of 304 wt%, 14-fold higher than the solid sample packed from the cage itself. The strong interactions between the nitrogen-rich sites and the adsorbed iodine species are revealed by spectral analyses. This work demonstrates that, utilizing the reticular chemistry strategy to extend the close-packed supramolecular organic cages into crystalline porous framework solids, their inherent properties can be greatly exploited for targeted applications.