含偶氮苯液晶弹性体的微纳结构构筑

发布时间：2018-01-05 06:24

本文关键词：含偶氮苯液晶弹性体的微纳结构构筑　出处：《苏州大学》2016年硕士论文　论文类型：学位论文

【摘要】：偶氮苯液晶聚合物,由于其同时具有了偶氮苯分子的光响应性和液晶的自组装的特性,在光响应性聚合物材料的研究领域得到了广泛关注。相比于普通液晶聚合物,偶氮苯分子光响应性的特点会对液晶性质产生显著影响,例如光引发的重新取向,光化学相转变以及光引起的分子协同运动等,这使得偶氮苯液晶聚合物具有光可控的特点。偶氮苯液晶弹性体同时结合了聚合物网络的弹性和液晶的有序性,使其对于外界微小的刺激可以产生很大的形状改变,从而实现光能向机械能的转变,在制动器,人造肌肉及生物材料领域都具有很多潜在的应用。此外巯基-烯反应作为点击反应的一种,具有不怕水氧阻聚等优点,广泛应用于各种聚合物的制备。本论文通过巯基-烯点击反应制备了偶氮苯液晶聚合物及液晶弹性体,研究其热力学性质和液晶相类型,探索了基于巯基-烯的光刻胶在激光直写中的应用潜力,制成微纳尺度的液晶弹性体并进一步研究了偶氮苯液晶基元在微纳结构中的取向行为。主要研究内容如下:(1)以往合成硅氧烷为主链的液晶聚合物,通常使用硅氢加成的方法,这种方法需要使用贵金属作为催化剂,并且在后期纯化时不易除去,此外通过硅氢加成反应得到的产物同时具有马氏加成与反马氏加成的产物,导致产物不纯,直接影响聚合物的液晶性。而巯基-烯反应作为点击反应的一种,具有很多优点。本文通过巯基-烯点击反应的方法,成功制备了侧链为偶氮苯的硅氧烷类液晶聚合物,通过核磁对其进行了化学结构的表征,证明通过此法可以获得硅氧烷为主链的液晶聚合物。随后通过使用差示扫描量热法(DSC),变温的偏光显微镜(POM)及变温的X射线衍射(XRD)对聚合物的相行为进行了研究。(2)双光子激光直写可以用于复杂的二维及三维微纳结构的制备,其原理是在激光的焦点处发生了双光子聚合,许多材料都已报道可运用于激光直写。基于巯基-烯反应具有反应速度快,不怕水氧阻聚,可以不需要引发剂及溶剂的优点,我们将偶氮苯液晶聚合物与交联剂及光引发剂共混,制成基于巯基-烯反应的光刻胶,将其应用于激光直写上并成功制备出了微纳尺度的液晶弹性体。通过对这种光刻胶进行不同能量不同直写速度的剂量测试,了解了该光刻胶使用的阈值,分辨率与特征尺寸,并据此选择合适的激光参数制备了各种复杂的二维及三维的液晶弹性体。(3)通过激光直写的方法,我们实现了激光诱导下液晶基元的取向。通过偏光显微镜和偏振的纳米红外研究了线条结构中液晶基元的择优取向,并通过扫描电子显微镜和偏振红外研究了取向度与线宽和激光能量的关系。同时,本文还用偏光显微镜观察了其它结构如圆及三维柴堆结构中液晶基元的取向行为,并成功制备了四取向的光栅,实现通过调整激光方向来控制液晶基元的取向。
[Abstract]:Azobenzene liquid crystal polymer, it is because of its responsiveness and self-assembly properties of azobenzene liquid crystal molecules of light, light response in research field of polymer materials has been widely concerned. Compared with the ordinary liquid crystal polymer, azobenzene photoresponsive characteristics will have a significant impact on the liquid crystal properties, such as light induced reorientation photochemical phase transition, and molecular light induced cooperative motion, which makes the azobenzene liquid crystalline polymer has the characteristics of light controllable azobenzene liquid crystal elastomer. Combined with the order of the elastic polymer network and liquid crystal, the outside for small stimuli can greatly change the shape, so as to realize the transformation of light energy to mechanical energy. The brake has a lot of potential applications in biomaterials and artificial muscle fields. In addition of thiol ene reaction as a click reaction, Has the advantages of no water oxygen inhibition, widely used in all kinds of preparation of polymer. The azobenzene liquid crystalline polymers and elastomers prepared by thiol ene click reaction system, study on the thermodynamic properties and phase type liquid crystal, explores the potential application of thiol ene photoresist based on laser direct writing system the liquid crystal elastomer, micro nano scale and further studies on the azobenzene mesogens in micro nano orientation structure. The main contents are as follows: (1) the synthesis of silicone liquid crystal polymer backbone, commonly used method of hydrosilylation, this method requires the use of precious metals as catalysts, and in the late stage purification is not easy to remove, in addition by the hydrosilylation reaction products obtained with Markovnikov and anti Markovnikov products, resulting in impure products, directly affect the liquid crystal polymer and thiol ene. As a response to the click reaction, it has many advantages. In this paper, through the method of thiol ene click reaction, successful preparation of the side chain azobenzene liquid crystal polymer siloxane, characterized by the chemical structure of the method is proved by NMR, silicone liquid crystal polymer backbone can be followed by using. Differential scanning calorimetry (DSC), polarizing microscope temperature (POM) and X ray diffraction (XRD) temperature on the phase behavior of polymer were studied. (2) the two-photon laser direct writing can be used for complex two-dimensional and three-dimensional micro nano structure preparation, its principle is the double photon polymerization in the focal point of the laser, many materials have been reported which can be used for laser direct writing. Based on the thiol ene reaction with fast response, not afraid of water oxygen inhibition, the advantages may not need the initiator and solvent, we will azobenzene liquid crystal polymer With the crosslinking agent and initiator were made of photoresist of thiol ene reaction based on its application in laser direct writing and successfully prepared liquid crystal elastomer micro nano scale. Based on the photoresist test different doses of different energy direct writing speed, understanding of the use of photoresist the resolution threshold and the feature size, and then select the appropriate laser parameters for preparing two-dimensional complex and liquid crystal elastic three-dimensional body. (3) by means of laser direct writing, we realized the laser induced liquid crystal element orientation. Through the nano infrared polarizing microscope and polarization of liquid crystal orientation the base line element structure, and by scanning electron microscopy and infrared polarization of orientation degree and width and laser energy. At the same time, this paper also used other structures such as circular polarized light microscopy and 3D woodpile structure was observed The orientation of the liquid crystal primitives is achieved and the four oriented grating is successfully prepared. The orientation of the liquid crystal base element is controlled by adjusting the direction of the laser.

【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O753.2;TQ317

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