共查询到18条相似文献,搜索用时 78 毫秒
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选用聚乙二醇二缩水甘油醚(EGDE)/季戊四醇缩水甘油醚(PERTGE)/1,8-二氨基-3,6-二氧杂辛烷(EDBEA)/向列相液晶(SLC1717)复合体系,在不同的固化条件下,通过热聚合诱导相分离方法制备了一系列电光性能不同的聚合物分散液晶(polymer dispersed liquid crystal,简称PDLC)膜.研究了固化温度和固化时间对制备的PDLC膜中聚合物网络的微观形貌和电光性能的影响.结果表明,随着固化温度的升高以及固化时间的缩短,PDLC膜的对比度、驱动电压和开态响应时间逐渐增大,而关态响应时间逐渐减小.在固化温度为363.2 K,固化时间为7 h时,所制备的PDLC膜具有较佳的电光性能. 相似文献
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多官能Iniferter制备聚合物分散液晶膜及其含量对电光性能的影响 总被引:1,自引:0,他引:1
采用可逆加成-断裂链转移(RAFT)、引发转移终止(Iniferter)活性自由基聚合法分步骤制备多官能Iniferter的大分子(RAFT-MI),并通过紫外光聚合诱导相分离法制备接枝共聚物为基体的聚合物分散液晶(PDLC)膜,研究了不同含量的RAFT-MI对PDLC膜的微观形貌、开态透光率、阈值电压(Vth)、饱和电压(Vsat)、对比度和记忆效应的影响.结果表明,当PDLC中的RAFT-MI含量从10%增加到30%时,开态透光率先增加,随后又逐渐降低,而Vth、Vsat逐渐降低,对比度先增加,然后又降低,记忆效应减弱. 相似文献
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全息聚合物分散液晶(HPDLCs)是由富聚合物相与富液晶相周期性排列而成的结构有序高分子复合材料.HPDLCs通过单体/液晶复合体系的光聚合诱导相分离而形成,如何调控并定量化描述复合体系的光聚合反应动力学、凝胶化行为和相分离程度,进而获得结构规整、电光性能优异的HPDLCs是关键难题.专论概述了光引发体系、单体结构、纳米无机材料掺杂对HPDLCs结构及性能的影响.光引发阻聚剂通过引发和阻聚的竞争与协同,降低了光聚合反应速率、延迟了凝胶时间,促进形成衍射效率达90%的HPDLCs.超支化单体降低了复合体系黏度和光聚合反应速率,延迟了凝胶时间,促使形成衍射效率达94%、具有一维光子晶体结构的HPDLCs.丙烯酰胺单体优化了相分离结构,将HPDLCs的衍射效率提升至98%.纳米硫化锌掺杂在保持规整结构和高衍射效率的同时,大幅降低了HPDLCs的驱动电压.研究还确定了HPDLCs的相分离程度与凝胶时间的函数关系.构建兼具高衍射效率与低驱动电压的HPDLCs,推进其在彩色3D图像存储等领域的应用仍是重要课题. 相似文献
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以丙烯酸-2-乙基己酯(EHA)、二甲基丙烯酸乙二酯(EDMA)/季戊四醇四丙烯酸酯(PETTA)为混合单体、液晶P0616A为液晶相、Irgacure 184为光引发剂,通过UV光引发制备了聚合物分散液晶(PDLCs),研究了不同烷基链长醇,即乙醇(EtOH)、正丁醇(nBA)、正己醇(nHA)、正辛醇(nOA)和正十四醇(nTA)对体系光聚合动力学及其PDLCs液晶相变温度及电光特性的影响.结果表明引入醇分子显著加快了丙烯酸酯/液晶复合体系的光聚合反应速率,提高了单体的最终转化率,其中以正丁醇体系最为明显.随着醇分子烷基链的增长,体系的转化率趋于降低,但依然明显高于不含醇的体系.醇分子的加入降低了PDLCs中液晶相的TNI,且随着醇分子烷基链长的增长,PDLCs液晶相的TNI总体上呈降低的趋势.醇分子的加入增加了PDLCs液晶微区中向列相液晶的含量,而含正丁醇和正十四醇的体系液晶微区中向列相液晶低于其它3个含醇体系.醇分子的加入明显降低了PDLCs的阈值电压和饱和电压以及对比度.结合体系的光聚合速率和单体转化率,正丁醇是改善PDLCs性能的最佳选择. 相似文献
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使用3种不同化学结构的单体材料制备了全息聚合物分散液晶光栅,并从光栅形貌、衍射能力、驱动特性、聚合物热稳定性4个方面评价了光栅的热稳定性.研究发现,含有刚性结构单体材料体系的光栅形貌、衍射能力等方面在200℃的温度下没有明显变化.表明光栅的热稳定性与单体材料的化学结构密切相关,单体材料中含有刚性结构有助于光栅热稳定性的提高.利用热重分析(TGA)对光栅中聚合物材料热分解温度进行了测定,并结合Freeman-Carroll微商法计算出了上述聚合物的分解活化能和分解反应级数.结果发现,含有刚性结构的聚合物材料的热分解温度、分解活化能和分解反应级数都高于柔性链结构材料,进一步验证了材料体系中刚性结构的添加有助于提高光栅的热稳定性. 相似文献
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采用N,N'-二(十二烷基)-N,N,N',N',N″-五甲基-1,4,7-三氮杂双碘化氨为Gemini表面活性剂,液晶为4-正戊基-4'-氰基联苯(5CB),通过微胶囊法制备了聚乙烯醇(PVA)分散液晶薄膜,着重研究Gemini表面活性剂对PVA分散液晶薄膜的微结构、电光特性的影响.结果表明,加入Gemini表面活性剂仅略微增加了PVA与5CB液晶的相容性,PVA分散液晶仍保持较高的相分离程度,但是Gemini表面活性剂使液晶微滴尺寸明显变小,液晶相均匀分散地于PVA基体中,液晶指向矢构型由两极型变化为径向型,PVA分散液晶薄膜的对比度和响应速度明显提高,同时保持较低的驱动电压. 相似文献
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新型液晶高分子膜的制备及其电光性能 总被引:1,自引:0,他引:1
采用聚合相分离原理制备了一种电光性能优良的新型液晶高分子膜—— PDLC膜. 从应用角度出发, 创新性地使用白光而非可见光区某一波长的光表征PDLC膜的性能参数, 如对比度、工作电压、响应视角等, 测试结果表明该膜工作电压为20 V、响应视角150°以上、寿命达105数量级且性能稳定, 同时比较了基片材质的影响, 发现塑料ITO基片制备的PDLC膜对比度性能更优越, 且容易制成大面积、可折叠的显示器件, 有着更广泛的应用价值. 该膜在传感器以及分析仪器元器件如新型光栅等方面已显示出其潜在的应用前景. 相似文献
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Fatima Zohra Abdoune Leila Benkhaled Lahcène Méchernène Ulrich Maschke 《Macromolecular Symposia》2011,303(1):100-107
Summary: The time relaxation of the optical transmission of polymer-dispersed liquid crystal films was investigated after application of an electric rectangular pulse. These films, consisting of liquid crystalline microdomains dispersed in a polymer matrix, were obtained by polymerization induced phase separation using ultraviolet and electron beam curing techniques. The effects of the curing procedure and film thickness on the transmission properties were investigated. The electro-optical response was expressed via a hierarchy of order parameters. A good agreement between the experimental data and calculated transmission values was found. 相似文献
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Yuzhen Zhao Jinqian Li Yang Yu Yang Zhao Zhun Guo Ruijuan Yao Jianjing Gao Yongming Zhang Dong Wang 《Molecules (Basel, Switzerland)》2022,27(21)
In this paper, inorganic oxide MgO nanoparticles-doped polymer dispersed liquid crystal (PDLC) films were made from a mixture of the prepolymer, SLC1717 liquid crystal, and MgO nanoparticles by the polymerization induced phase separation (PIPS) process. To observe the effect of MgO concentration, PDLC was dispersed with 0.2, 0.4, 0.6, and 0.8 wt.% MgO. Electro-optical properties of the films have been investigated using LCD parameter meter and Scanning Electron Microscope (SEM) at room temperature. It is established that MgO nanoparticles affect the microstructure of PDLC films significantly because of the formed agglomerates of MgO nanoparticles. Results show an improvement in the electro-optical properties and a decrease in the driving voltage for doped systems with MgO nanoparticles. When the doping amount of MgO is 0.8 wt.%, the threshold voltage (Vth) is reduced to about 7.5 V. Therefore, MgO-doped PDLC is expected to become an excellent choice in the field of energy-saving. 相似文献
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Young Jae Jeon Yin Bingzhu June Tak Rhee David L. Cheung Muhammad Jamil 《Macromolecular theory and simulations》2007,16(7):643-659
Polymer‐dispersed liquid crystals (PDLCs) represent an important new class of materials with electro‐optic applications such as flexible displays, large‐area devices projection displays, electrically switchable windows, etc. On considering such applications of these materials, many studies have been performed on the experimental side. Similarly, research on the simulation side for the PDLCs is of the fundamental interest too. The present article contains a short review on the present and past simulation studies of PDLCs. Various molecular simulation approaches applied to PDLC systems by different groups are reviewed here. In addition some new findings of the bulk phases are also extensively described.
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Mohsin Hassan Saeed Shuaifeng Zhang Yaping Cao Le Zhou Junmei Hu Imran Muhammad Jiumei Xiao Lanying Zhang Huai Yang 《Molecules (Basel, Switzerland)》2020,25(23)
Polymer dispersed liquid crystals (PDLCs) have kindled a spark of interest because of their unique characteristic of electrically controlled switching. However, some issues including high operating voltage, low contrast ratio and poor mechanical properties are hindering their practical applications. To overcome these drawbacks, some measures were taken such as molecular structure optimization of the monomers and liquid crystals, modification of PDLC and doping of nanoparticles and dyes. This review aims at detailing the recent advances in the process, preparations and applications of PDLCs over the past six years. 相似文献
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A homogeneous solution of a low‐molecular‐weight liquid crystal and a polymer spontaneously phase separates during airbrushing to form uniform fibers with a fluid liquid‐crystal core surrounded by a solid polymer sheath. This structure forms because it effectively minimizes the interfacial energy of the phase‐separated components while minimizing the elastic energy of the liquid‐crystal core. These fibers incorporate the sensitive stimuli response of liquid crystals while maintaining the structural integrity, flexibility, and large surface‐area‐to‐volume ratios inherent in fibers. We demonstrate the electro‐ and thermo‐optical response of the resulting fibers. They may find use as biological and chemical sensors. The resulting fibers have the potential to shape the future of flexible/wearable electronics and sensors. 相似文献
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Gia Petriashvili Maria Penelope De Santo Lali Devadze Tsisana Zurabishvili Nino Sepashvili Ramla Gary Riccardo Barberi 《Macromolecular rapid communications》2016,37(6):500-505
Rewritable optical storage has been obtained in a spiropyran doped liquid crystal polymer films. Pictures can be recorded on films upon irradiation with UV light passing through a grayscale mask and they can be rapidly erased using visible light. Films present improved photosensitivity and optical contrast, good resistance to photofatigue, and high spatial resolution. These photochromic films work as a multifunctional, dynamic photosensitive material with a real‐time image recording feature.
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用X-射线衍射法详细研究了ChN/Poly(MMA-co-BMA)共混体系在胆甾相,近晶相及结晶态的分子排列,并给出了将液晶的分子排列冻结在体系中的,从而实现信息存储功能的条件。 相似文献