含对硝基偶所苯基团的侧链液晶高分子的合成及其光致变色性能研究

报道了新型的含对硝基偶氮苯基团的甲基丙烯酸酯单体与含介晶基团的甲基丙烯酸酯单体扔合成及其自由基共聚合，利用＾１Ｈ－ＮＭＲ，ＩＲ，ＵＶ－Ｖｉｓ，ＧＰＣ元素分析，ＤＴＡ及ＰＯＭ等手段对偶氮单体和聚合物进行了结构表征。证明两种单体的共聚合产物为无规共聚物，而且各聚合物在加热过程中均显示出明显的向列相液晶织构。     

含对甲氧基苯氧羰基偶氮苯基团的侧链液晶高分子的合成与表征

报道了新型的含对甲氧基苯氧羰基偶氮苯基团的甲基丙烯酸酯单体与含对甲氧基苯氧羰基苯基团的甲基丙烯酸酯单体的合成及其自由基共聚合．利用１Ｈ ＮＭＲ、ＩＲ、ＵＶ Ｖｉｓ、元素分析、ＧＰＣ、ＴＧ ＤＴＡ、ＰＯＭ及Ｘ 射线衍射等手段对偶氮单体及聚合物的结构与性能进行了表征,证明两种单体的共聚合产物为无规共聚物,而且各聚合物均具有较好的热稳定性．研究结果还表明,偶氮单体与聚合物在升温过程中均显示出向列相液晶织构,且聚合物的液晶相范围随偶氮含量的增加而变宽．     

含对甲氧基苯氧羰基偶氮苯基团的侧链液晶高分子的光致变色性能研究

研究了含对甲氧基苯氧羰基偶氮苯基团的甲基丙烯酸酯单体及其与含对甲氧基苯氧羰基苯基团的甲基丙烯酸酯单体的共聚物的氯仿溶液、二甲基甲酰胺溶液和共聚物薄膜在紫外光诱导下的光异构化及热回复异构化行为。结果表明,它们在紫外光诱导下均能发生先致变色现象,且介质对其光致变色行为起决定作用。     

含对甲氧基苯氧羰基偶氮苯基团的侧链液晶高分子的光致变色 …

研究了含对甲氧基苯氧羰基偶氮苯基团的甲基丙烯酸酯单体及其与含对甲氧基苯氧羰基苯基团的甲基丙烯酸酯单体的共聚物的氯仿溶液,二甲基甲酰胺溶液和共聚物薄膜在紫外光诱导下的光导构化及热回复异构化行为。结果表明,它们在紫外光诱导下均能发生光致变色现象,且介质对其光致鸾以行为起决定作用。     

液晶基元直接竖挂于主链上的液晶共聚物的研究

合成了含液晶基元的单体，４＋４＇－（对甲氧基－苯甲酰氧基）－苯甲酸氧基］－苯基－甲基丙烯酸酯，以及由此单体与苯乙烯，通过自由基共聚合反应合成了一系列含液晶性和非液晶性两种序列结构的共聚物．采用ＤＳＣ、偏光显微镜和Ｘ－衍射方法研究了共聚物的液晶行为，发现单体和所有的共聚物（除ＣＰ—９外）均有很好的热致液晶性及较宽的液晶态温度范围；随苯乙烯单体单元摩尔百分含量的增加，共聚物的分子量、相转变温度和热失重温度基本上呈下降趋势．通讯联系人０．ｓｇ／ｄｌ的溶液，于４０ｏＣ用乌氏粘度计测定．ｌ·２单体合成合成路线如下：化合物Ｉ、１１、Ｉｌｌ和ＩＶ的制备按文献ｌ’］的方法进行．化合物１、１１、Ｉｌｌ和ＩＶ经元素分析、‘Ｈ—ＮＭＲ和ＭＳ等表征，结果与其化学结构～致．１．３聚合物的合成聚合反应和共聚物结构式表示如下：按单体（ＩＶ）与苯乙烯不同摩尔比，以ＤＭＦ为溶剂，ＡＩＢＮ为引发剂（相当于单体摩尔数的０．５０）．通过封管聚合，在６０ｏＣ水浴中反应３６ｈ，升温至７０ｏＣ反应１２ｈ，抽滤，用ＤＭＦ和甲醇洗，真空干燥．２结果与讨论２．ｌ含液晶基元的单体（Ｉ）化合物１、１１、Ｉｌｌ和ＩＶ经测试分析结果与其化学结构一致．由表１可见，单体?     

含偶氮基团的聚甲基丙烯酸酯型侧链液晶高分子的合成与表征

报道了一种新的含对甲氧基苯氨羰基偶氮苯基团的甲基丙烯酸酯单体及其自由基聚合产物的合成。利用元素分析,＾１Ｈ－ＮＭＲ、ＵＶ－Ｖｉｓ、ＧＰＣ、ＴＧ－ＤＴＡ、ＰＯＭ及Ｘ－射线衍射等手段对其结构与性能进行了表征。结果表明,偶氮单体不具有液晶性质,而聚合物则具有向列型液晶相存在,并且它在空气中具有很好的热稳定性。     

含硝基偶氮苯侧基的丙烯酸酯液晶聚合物的合成,结构与性…

以含硝基偶氮苯侧基的丙烯酸酯液晶聚合物为研究对象，利用ＤＳＣ、ＷＡＸＤ、偏光显微镜等手段研究了分子结构对侧链液晶聚合物结晶行为的影响。结果表明：丙烯酸酯类液晶聚合物的晶区是由介晶基团的规整排列形成的，大分子主链和柔性间隔基不参与结晶。随着柔性间隔基长度的增加，晶区分子排列有序性提高，结果度增大；非晶共聚组分ＭＡ含量的增加，限制了介晶基团的有序排列，当ＭＡ含量超过８３％后，只得到非晶共聚物。     

光致变色液晶高分子研究（Ⅲ）──含胆甾介晶基元和偶氮苯光色基元侧链共聚硅氧烷的液晶行为

用热台偏光显微镜、Ｘ射线衍射和ＤＳＣ研究了含胆甾介晶基元和偶氮苯光色基元侧链共聚硅氧烷（ＰＳＩ）的液晶性．将非介晶基元并入液晶均聚物，所得共聚物的液晶态类型不变，仍显示近晶型织构，在ＰＳＩ共聚物中，保持液晶性的含介晶基元单体的最低极限组成为６０ｍｏｌ％．在液晶性存在的范围内，共聚物的清亮点由１３０℃升至１７０℃，液晶共聚物的热稳定性随非介晶组分含量的增加而增强．     

含有联苯和肉桂酸酯基团的侧链液晶共聚物的合成与表征

合成了两种含有联苯刚性基元的甲基丙烯酸酯单体M1和M2,其中M1为含有可光交联的肉桂酸酯端基的单体.通过溶液自由基聚合,得到一系列含不同比例M1和M2单体单元的聚丙烯酸酯类侧链液晶共聚物.采用1H-NMR、FT-IR等方法对单体和聚合物的结构进行了详细表征.用示差扫描量热法、偏光显微镜以及广角和小角X-射线衍射对单体和聚合物的液晶性进行了研究.结果表明,末端为肉桂酸酯基团的单体M1无液晶性,其均聚物P1有微弱的液晶性,而端基为正丁基的单体M2及其均聚物P9则表现出近晶相液晶行为.共聚物P2~P5均为向列型液晶,P6~P9则为近晶型液晶.随在聚合物中M2单体含量的增加,共聚物的玻璃化转变温度、熔点及清亮点温度均呈现增加趋势.     

光致变色液晶高分子研究（Ⅲ）：含胆甾介晶基元和偶氮苯…

用热台偏光显微镜、Ｘ射线衍射和ＤＳＣ研究了含胆甾介晶基元和偶氮苯光色基元侧链共聚硅氧烷（ＰＳＩ）的液晶性。将非介晶基元并入液晶均聚物，所得共聚物的液晶态类型不变，仍显示近晶型织，在ＰＳＩ共聚物中，保持液晶性的含介晶基元单体的最低极限组成为６０ｍｏｌ％．在液晶性存在的范围内，共聚物的清亮点由１３０℃升至１７０℃，液晶共聚物的热稳定性随非晶组分含量的增加而增强。     

Silicon‐containing azo polymers with paired mesogens and their applications to optical memory media

We synthesized a novel photoresponsive monomer, silicon‐containing azo monomer with paired mesogens in the side chain, by reacting 3‐methacryloxypropylmethyldichlorosilane with 2‐[2‐(4‐cyano‐azobenzene‐4′‐oxy)ethylene‐oxy]ethyl alcohol, a mesogenic group. Corresponding homopolymer and copolymers with methyl methacrylate were generated via radical polymerization with AIBN as a radical initiator. Investigations of their thermal properties and optical textures confirmed the monomer and the homopolymer have smectic structures. Homo‐ and copolymer films showed high potential as reversible data recording media via photoinduced alignment of azobenzene groups with irradiation of a linearly or circularly polarized light. Out of all the samples, the copolymer films with high azo dye contents showed the best resolution in the recorded data as well as the fastest response to a pump beam due to large optical birefringence induced in a write‐in process. Strong dependence of the stability of the data stored in the films on the glass transition temperature of the polymers was also observed. In addition, high‐quality holographic grating patterns were inscribed even on the copolymer film with azo molar content of only 7.0% using a modified two‐wave mixing technique. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6734–6745, 2008     

SYNTHESIS AND CHARACTERIZATION OF COMB-LIKE POLYMERS BEARING HETEROCYCLIC AZO GROUP AND MESOGENIC GROUP

The synthesis and characterization of a series of novel comb-like polymethacrylates bearingheterocyclic azo group and mesogenic group are described. The thermal properties of the polymers such asthermal stability and phase transition behavior were investigated by thermogravimetric analysis, differentialthermal analysis and polarizing optical microscopy techniques. The experimental results show that all thesynthesized polymers do not exhibit liquid crystallinity except the homopolymer of the mesogenic monomerMAPB2 and the glass transition temperatures of the polymers increase with increasing content of azo moietyin polymers linearly.     

Behaviors of self‐assembled diblock copolymer with pendant photosensitive azobenzene segments

A novel monomer, ethyl 4‐[4‐(11‐methacryloyloxyundecyloxy)phenyl azobenzoyl‐oxyl] benzoate, containing a photoisomerizable N?N group was synthesized. The monomer was further diblock copolymerized with methyl methacrylate. Amphiphilic diblock copolymer poly(methyl methacrylate‐block‐ethyl 4‐[4‐(11‐methacryloyloxyundecyloxy)phenyl azobenzoyl‐oxyl] benzoate ( PMMA ‐ b ‐ PAzoMA ) was synthesized using atom transfer radical polymerization. The reverse micelles with spherical construction were obtained with 2 wt % of the diblock copolymer in a THF/H₂O mixture of 1:2. Under alternating UV and visible light illumination, reversible changes in micellar structure between sphere and rod‐like particles took place as a result of the reversible E‐Z photoisomerization of azobenzene segments in PMMA ‐ b ‐ PAzoMA . Microphase separation of the amphiphilic diblock copolymer in thin films was achieved through thermal and solvent aligning methods. The microphases of the annealed thin films were investigated using atom force microscopy topology and scanning electron microscopy analyses. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1142–1148, 2010     

含不同基团偶氮苯化合物的合成及其光致异构化性质

以苯胺或对硝基苯胺为起始原料,通过重氮偶合法合成了4种分别含有硝基、氨基和不同数目偶氮基的偶氮苯化合物(1~4),其结构经¹H NMR和FT-IR确证。研究了1~4在紫外灯(12 W)照射下随时间变化的UV-Vis谱图。结果表明：含有给电子基团(NH₂)偶氮苯的光致异构化速率较含有吸电子基团（NO₂）时更快,NO₂对分子的异构化有一定抑制作用;分子中偶氮基的数目增加时,顺反异构化过程也受到影响。     

Synthesis of a liquid crystalline azobenzene monomer for photoalignment of ferroelectric liquid crystals

A liquid crystalline dimethacrylate-based monomer containing an azobenzene group was synthesized. The miscibility of the azo monomer and its crosslinked polymer network with ferroelectric liquid crystals (FLCs) was improved by the liquid crystallinity of the monomer. By performing thermal polymerization of the azo monomer dissolved in a FLC host under linearly polarized visible light irradiation, following a pre-irradiation with unpolarized UV light at room temperature, bulk alignment of the FLC could be induced in the absence of surface orientation layers, as a result of the photo-orientation of azobenzene moieties related to the reversible trans-cis photoisomerization of the chromophore. The optical and rubbing-free alignment of a FLC could be achieved with as few as 0.5 wt % of the azo polymer network. This represents a step toward the preparation of uniform samples of photoaligned FLC by reducing the amount of the azo polymer network that may be phase-separated from the FLC host.     

Preparation of side‐on bisazobenzene‐containing homopolymers and block copolymers via ATRP and studies on their photoisomerization and photoalignment behaviors

The preparation of a series of novel homopolymers and copolymers containing bisazobenzene chromophores with side‐on structure in the side chains via atom transfer radical polymerization (ATRP) were presented. UV–vis spectra of the thin films of these polymers under irradiation of 488 nm Ar⁺ laser suggested that the photoisomerization of the bisazobenzene chromophores happened mainly on one of the two azo groups in the bisazobenzene chromophores with similar probability due to their side‐on structure. Good photoalignment behaviors of these polymers were proved by photoinduced birefringence measurements because side‐on structure permitted the two azo groups in the bisazobenzene chromophores both participated in the trans–cis–trans photoisomerization cycles equally to induce the whole chromophore reorientation. Furthermore, the reorientation axis located at the middle of chromophore decreased the sweep volume during photoalignment. The impetus for this study was to evaluate the photoisomerization and photoalignment process of side‐on bisazobenzene‐containing polymers and to find possible applications in the photosensitive devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3460–3472, 2007     

Synthesis and characterization of chiral azo LCPs with optical properties

ABSTRACT

In this study, we designed, synthesised and characterised two series of cholesteric liquid crystal polymers, QP series and ZP series. With polymethylhydrosiloxane as the main chain, QP series were synthesised by copolymerisation between the monomer M₁ containing a cholesteryl mesogenic unit and the monomer M₂ with a hydroxyl. ZP series, meanwhile, were synthesised by esterification between QP series members and the monomer M₃, a carboxylic acid with an azo mesogenic unit. We characterised chemical structures of all the monomers and polymers by FT-IR and ¹H-NMR, which proved that the target monomers and polymers had been obtained. We observed dramatic colour changes after the introduction of monomer M₃ and Grandjean textures from both QP series and ZP series using POM. In addition, strong selective reflection could be observed as well. Then, we characterised the thermal properties of polymers by DSC, TGA and XRD to explore their phase transition behaviours further. Their photoresponsive and photochromic properties were characterised by UV-Vis spectrum.     

Synthesis and characterization of conjugated polymer containing azobenzene and oxadiazole units

A novel conjugated polymer containing azobenzene and oxadiazole units was synthesized through multi-step synthesis.The structures and properties of monomer and polymer were characterized and evaluated with IR,1H NMR,UV,TGA and GPC,respectively.Polymer with long side chain of alkoxy shows good solubility,thermal stability and photoisomerization property.