具有响应机制的功能化液晶弹性体材料研究进展

液晶弹性体材料结合了液晶基元的刚性和弹性体的柔性，克服了传统热塑性弹性体存在强度低、回弹性差等缺陷，成为近年来研究发展的热点。综述液晶弹性体的合成工艺及其优缺点，介绍液晶弹性体特殊的热学性能、分子取向性和力学性能，阐述液晶弹性体满足光、热、电、湿度及磁响应需求的功能化设计，简述液晶弹性体在4D打印、人工肌肉、柔性机器人等领域的应用，指出未来液晶弹性体要向提高综合性能，可便捷加工，具备多种复杂响应性能的方向发展。     

介电弹性体智能材料的研究进展

介电弹性体作为一种新型电活性聚合物,能在电场作用下产生较大驱动力与驱动变形,具有弹性能量密度高、高效和应变响应速度快等优点,广泛用于人工肌肉、微型驱动器、机器人和消音减振系统等领域。从聚合物/陶瓷和聚合物/导电相2相复合材料以及陶瓷/导电相/聚合物3相复合材料方面介绍了目前介电弹性体的研究现状和存在问题,并指出了介电弹性体今后的发展方向。     

液晶弹性体的研究进展

综述了液晶弹性体,主要是侧链液晶弹性体、主链液晶弹性体的合成方法,液晶弹性体的热弹性、光弹性、压电性、机械力场下的取向性、溶胀行为以及形变中内能与熵的作用等物理性质,介绍了其在人工肌肉、纳米机械、人工智能、形状记忆等方面的潜在应用前景及最新研究成果.     

液晶弹性材料制备先进传感器

正你能想象液晶的弹性体吗?你能想象液晶弹性体作为先进传感器吗?肯特州立大学的Peter Palffy-Muhoray博士带你认识他们首次开发出来的不可思议的液晶弹性体。液晶弹性体(LCEs)本质上来讲就是具备液晶性能的橡胶,利用它可以做很多不可思议的事情,尤其是在光学、光电子学、通信行业以及药学领域。当遇到光,热,气或者其他刺激因素时,     

液晶弹性体的研究进展

本文综述了液晶弹性体的最新进展,主要是主链型液晶弹性体、侧链型液晶弹性体以及混合型液晶弹性体的取向性、压电性、铁电性与软弹性等性质,并阐述了液晶弹性体在传感器、驱动器以及仿生机械领域的研究成果与应用前景。     

具有形状记忆效应的液晶弹性体研究进展

综述了形状记忆聚合物（SMPs）的研究及应用现状,详细介绍了具有形状记忆性能的液晶弹性体的主要类型,包括热致形变液晶弹性体、光致形变液晶弹性体、电致形变和化学刺激导致形变液晶弹性体的形变机理及研究进展。最后,对液晶弹性体的发展前景进行了展望。     

产品开发

正环境刺激响应型高强智能水凝胶研发引人瞩目环境刺激响应型智能水凝胶能够对外界环境因素的变化产生显著的体积或其他特性的变化,且其性质和结构与生物组织类似,有望应用于传感器、人工肌肉、软体机器人、组织工程、化学反应开关或微阀、物质分离、药物控释等许多领域,具有很重要的意义和经济价值,其研发引人注目。近年来研发的主要有四类不同结构的环境刺激响应型高强智能水凝胶:超低交联结构水凝胶、纳米颗粒复合水凝胶、双网     

偶氮苯液晶弹性体中不同的交联类型

偶氮苯液晶弹性体材料结合了偶氮化合物的光响应性、液晶的各向异性、聚合物的熵弹性的优点,偶氮苯液晶弹性体在光照(紫外光/可见光)的作用下可以利用分子间的协同作用将微观的光致异构化转变为宏观的形变,实现了将光能直接转化成机械能,而这一过程的实现离不开聚合物的交联作用。并且随着交联方式的不断改变,聚合物种类和性能也随之不断发展,比如聚合物的加工性能、光响应性等。本文主要根据交联方式的不断改变,阐述了偶氮苯液晶弹性体的发展。     

液晶聚合物

液晶聚合物 (ＬＣＰ)是新型的高分子材料 ,在熔融态时一般呈现液晶性 ,这类材料具有优异的耐热性能和成型加工性能。ＬＣＰ具有优异的耐热、难燃、耐药品性 ,注射成型时流动性好 ,线膨胀系数小 ,成型收缩率低等特点。其成型产品具有液晶聚合物特有的皮芯结构 ,树脂本身具有纤维性质 ,在熔融状态下有高度的取向 ,故可起到纤维增强的效果。这是液晶聚合物最引人注目的特点。热致性液晶 (ＴＬＣＰ)其耐热分为三种类型 :Ⅰ型的热变形温度为 2 5 0 - 35 0℃ ;Ⅱ型热变形温度为 180 -2 4 0℃ ;Ⅲ型热变形温度为 6 0 - 80℃。液晶聚合物合金化的主…     

液晶聚合物

液晶聚合物 (ＬＣＰ)是新型的高分子材料 ,在熔融态时一般呈现液晶性 ,这类材料具有优异的耐热性能和成型加工性能。ＬＣＰ具有优异的耐热、难燃、耐药品性 ,注射成型时流动性好 ,线膨胀系数小 ,成型收缩率低等特点。其成型产品具有液晶聚合物特有的皮芯结构 ,树脂本身具有纤维性质 ,在熔融状态下有高度的取向 ,故可起到纤维增强的效果。这是液晶聚合物最引人注目的特点。热致性液晶 (ＴＬＣＰ)其耐热分为三种类型 :Ⅰ型的热变形温度为 2 5 0～ 35 0℃ ;Ⅱ型热变形温度为 180～2 4 0℃ ;Ⅲ型热变形温度为 6 0～ 80℃。液晶聚合物合金化的主…     

Tunable Artificial Iris Controlled by Photo/Thermal Exposure Based on Liquid Crystalline Elastomers

The iris, part of the eye structure, is an important tissue in organisms. Here, a tunable artificial iris showing widening and closing of the pupil in response to near-infrared (NIR) light is demonstrated. Liquid crystalline elastomers (LCEs) are synthesized via Michael addition and photopolymerization. To prepare an artificial iris, a predesigned stainless steel mold with a specific structure is created for the preparation of a single shaped LCE piece. Through the assembly of individual shaped LCE pieces, an artificial iris is fabricated. To enhance the photosensitivity, polydopamine (PDA) is coated on the surface of the fabricated iris. The PDA-coated artificial iris shows reversible pupil widening and closing via exposure to NIR light. The dependence of pupil size on NIR intensity shows a function similar to the human iris. As far as it is known, the fabricated artificial iris with 2D radial motion is the first example prepared from a liquid crystalline elastomer showing a tunable aperture size controlled by the surrounding light intensity. The synthesized artificial iris is expected to show potential for multiple applications in biomimicry and biomedical science.     

Programmable liquid crystal elastomer matrix through photomechanical responses

Considering the dependence of photomechanical responses of liquid crystal elastomers on the director orientation, the performance controlling through director orientation design becomes possible. In this article, a programmable liquid crystal elastomer matrix is proposed to achieve the desired functions. First, a modeling framework about the spontaneous bending of liquid crystal elastomer square plate with arbitrary director orientation is developed. Three kinds of spontaneous bending configurations are obtained along with the variation of the director orientation, and the critical division of the director orientation is given. Based on the deformation characteristic, the director orientation of the liquid crystal elastomer matrix is programmed and several typical prototypical functions, such as 3D code or image display, are discussed. This work provides the guidance for the application of the liquid crystal elastomer in haptic display, braille display, remotely-controlled actuators, and codes.     

液晶聚合物纤维的牵引工艺与性能

通过单螺杆挤出机挤出,利用牵引机的不同牵引速度获得不同液晶聚合物纤维试样,采用万能试验机、电子显微镜扫描(SEM)分析其力学性能和内部取向.结果表明:随着牵引速度增大,其内部的取向逐渐规整,内部组成的微纤排列越紧凑,导致液晶聚合物纤维的弹性模量增大;同时,当牵引速度到达一定数值时,取向程度不再增大,液晶聚合物纤维的弹性模量呈下降趋势;在一定时间段内,经过温度为150℃的后处理,将使液晶聚合物纤维内部分子结构达到更完善的取向状态,力学性能有所提高.     

Study on the Optical and Mesomorphic Properties of Cholesteric Side-Chain Liquid Crystalline Elastomers Containing a Nematic Cross-Linking Agent

To study the effect of the content of the nematic cross-linking units on the mesophase behaviors, the optical and mesomorphic properties of liquid crystalline elastomers (LCEs), aseries of LCEs have been synthesized by hydrosilylation reaction with poly(methylhydrogeno)siloxane, a cholesteric liquid crystalline monomer, and a nematic cross-linking agent. The chemical structures and properties of the synthesized LCEs have been investigated by use of various techniques. Homopolymer P₀ bearing only cholesteric component displays a smectic A phase, but elastomers P₁-P₅ containing different content of nematic cross-linking units show a cholesteric mesophase. The reflection wavelengths of theLCEs show a weak temperature dependence at lower temperatures but a strong temperature dependence at higher temperatures. Furthermore, the maximum reflection wavelengths of the LCEs can be stabilized over a wide temperature range when the LCEs are heated, suggesting that the helical structure and pitch of the cholesteric phase can be stabilized with a polymer network.     

Effect of molecular parameters on thermomechanical behavior of side-on nematic liquid crystal elastomers

We investigated the structure–property relationship of liquid crystal elastomers (LCEs) obtained from a series of nematic side-on monomers. A new synthetic strategy was developed to obtain the acrylate monomers (n-ADBB), which gave us the opportunity to easily modify the spacer lengths of the monomers. Through magnetic field alignment, well-defined LCE micropillars were fabricated from the monomers by a method combining soft lithography and photopolymerization/photocrosslinking of the monomers and a crosslinker. The influence of structural parameters on the thermomechanical deformation of the microstructures was studied through microscopic observations. The study quantitatively revealed the correlation of thermomechanical behavior of the microstructured LCEs with the crosslinking density and length of the flexible spacer linking the mesogenic core to the backbone. With a proper control of the structural parameters, optimized performances such as large reversible contraction, good elasticity and mechanical robustness were demonstrated for this type of LCEs.     

高分子液晶材料的应用及发展趋势

液晶相是不同于固相和液相的一种中介相态。系统地阐述了液晶的发现、形成机制以及分类,简单介绍了液晶高分子的结构特点,介绍了主链型和侧链型液晶高分子研究的新进展,并对液晶在各个领域的应用研究和潜在性能进展作了简要的阐述。     

Liquid crystalline elastomers based on diglycidyl terminated rigid monomers and aliphatic acids. Part 1. Synthesis and characterization

Liquid crystalline elastomers (LCEs) were prepared by reacting rigid-rod mesogenic epoxy monomers with aliphatic diacids of variable length. The influence of acid and nature of epoxy monomer on the mechanism of network growth was investigated through DSC, FT-IR, MALDI, ¹H and ¹³C NMR and rheological experiments. Depending on the nature of epoxy monomer, different mechanisms of network growth occurred, which were responsible for the formation of elastomers with different extent of branching.Clearing temperatures, enthalpies and entropies, and the nature of mesophases were also analyzed through DSC and X-ray diffraction, carried out on unstrained elastomers. It was found that both the rigid-rod mesogens and the aliphatic portions of carboxylic acids contribute to stabilize the mesophase. Moreover, upon stretching, all the LCEs exhibited the polydomain-to-monodomain transition, which is typical of this class of materials.     

Development of Piezoelectric Elastomers and Their Applications in Soft Devices

Piezoelectric materials have wide-ranging applications owing to their capacity to convert mechanical energy into electrical energy in daily life scenarios. With rapid development in fields such as wearable electronics, intelligent electronic products, and medical equipment, the requirement for the elasticity of piezoelectric materials has become increasingly stringent. However, combining high piezoelectric performance with high elasticity in most conventional piezoelectric materials is challenging, limiting the application of piezoelectric elastomers in complex scenarios. Recently, several piezoelectric elastomer materials with good flexibility, high elasticity, and easy processing ability have been reported, and their applications in soft devices have rapidly developed. In this review, the current state of piezoelectric elastomers and their applications are systematically reviewed. Additionally, an overview of trends in the development of piezoelectric elastomer materials is given, providing a reference for future research in this field.