Liquid Crystals

液晶
  • 文章类型: Journal Article
    背景:该研究对四种不同的半氟化手性有机活性铁电液晶(OAFLC)进行了比较分析。通过使用各种参数对化合物进行比较分析,包括热力学,非线性光学,电气,原子电荷分布,和原子取向。我们使用优化算法来研究化学反应性,电性能,分子间相互作用,和静态超极化率。样品4是宽范围的显示器应用的最佳选择。这项研究有助于理解半氟化手性OAFLC的细微差别的性质,并突出样品4在显示技术中的新应用潜力。由于其优越的稳定性和优化的性能。这项研究通过纳入关键研究的发现,有助于增强我们对半氟化手性OAFLC的比较分析的理解,以实现显示技术的潜在进步。
    方法:使用密度泛函理论(DFT)进行模拟,其中B3LYP功能用于预测分子性质,和振动能量分布分析(VEDA)软件用于执行分子的振动分析。
    BACKGROUND: The study undertakes a comparative analysis of four distinct semi-fluorinated chiral Organic Active Ferroelectric Liquid Crystals (OAFLCs). The comparative analysis of the compounds is done by using various parameters, including thermodynamic, non-linear optical, electrical, atomic charge distribution, and atomic orientations. We use optimization algorithms to look at chemical reactivity, electrical properties, intermolecular interactions, and static hyperpolarizability. Sample 4 is the best choice for a wide range of display applications. This research contributes to understanding the nuanced properties of semi-fluorinated chiral OAFLCs and highlights Sample 4\'s potential for novel applications in display technology, owing to its superior stability and optimized properties. This study helps to enhance our understanding of the comparative analysis of semi-fluorinated chiral OAFLCs for potential advancements in display technologies by incorporating findings from key studies.
    METHODS: The simulations are performed using density functional theory (DFT) with the B3LYP functional for predicting molecular properties, and Vibrational Energy Distribution Analysis (VEDA) software is used to perform the vibrational analysis of the molecules.
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  • 文章类型: Journal Article
    通过在向列型液晶中使用胶体颗粒,可以以缠结的向错线的形式实现软凝聚态系统中的缠结。这些拓扑激发表现为平衡时的胶体缠结。如何进一步利用非平衡旋转线来操纵胶体纠缠仍然是一项艰巨而具有挑战性的任务。在这项工作中,我们使用实验和模拟来证明向列胶体纠缠在光驱动的向错线时空演化中的重新配置。胶体缠结可以感知错线拓扑结构的细微变化,实现手性转换。这种转换表现为胶体在旋转线中的集体旋转的“多米诺效应”。通过编程拓扑图案和旋转错线的几何形状,胶体缠结可以组装和分裂。更值得注意的是,通过控制旋转错线的形态变化可以形成双螺旋缠结结构。因此,这项工作将为智能材料和微型机器的胶体复合材料编程提供机会。
    Entanglement in a soft condensed matter system is enabled in the form of entangled disclination lines by using colloidal particles in nematic liquid crystals. These topological excitations are manifested as colloidal entanglement at equilibrium. How to further utilize nonequilibrium disclination lines to manipulate colloidal entanglement remains a nontrivial and challenging task. In this work, we use experiments and simulations to demonstrate the reconfigurations of nematic colloidal entanglement in light-driven spatiotemporal evolutions of disclination lines. Colloidal entanglement can sense subtle changes in the topological structures of disclination lines and realize chirality conversion. This conversion is manifested as the \"domino effect\" of the collective rotation of colloids in the disclination lines. By programming the topological patterns and the geometry of the disclination lines, colloidal entanglement can be assembled and split. More remarkably, a double-helix entangled structure can be formed by controlling the changes in the morphology of the disclination lines. Thus, this work will provide opportunities to program colloidal composites for smart materials and micromachines.
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  • 文章类型: Journal Article
    在天然存在的光收集复合物(LHC)中复制微结构基础和接近100%的激发能量转移效率在合成能量收集装置中仍然具有挑战性。生物光合作用调节蛋白质中光吸收和漏斗叶绿素的活性集合,以响应阳光的波动。这里,据报道,使用远程液晶(LC)排序来定制液晶共轭聚合物(LCCP)层中的链取向和堆积结构,以实现LHC的某些结构基础和集光性能的生物模仿。发现聚(9,9-二辛基芴-共-苯并噻二唑)(F8BT)共聚物的LC相中的长程取向有序化稳定了分散在F8BT链的无定形基质中的一小部分随机取向的F8BT纳米晶体,类似于自掺杂的主客体系统,通过触发3D供体到受体Förster共振能量转移(FRET)和纳米晶体受体中的主要链内发射,可以显着提高激发能量漏斗和光致发光量子效率。Further,向列F8BT层的光对准与LC取向排序相结合,以制造具有>60%结晶度和≈20nm长的链间堆积顺序的大面积扩展单畴。值得注意的是,这些单畴表现出强烈的线性极化发射,同时与非对齐膜相比还促进新的能带边缘吸收物质和额外的发射链间激发态。
    Replicating the microstructural basis and the near 100% excitation energy transfer efficiency in naturally occurring light-harvesting complexes (LHCs) remains challenging in synthetic energy-harvesting devices. Biological photosynthesis regulates active ensembles of light-absorbing and funneling chlorophylls in proteins in response to fluctuating sunlight. Here, use of long-range liquid crystal (LC) ordering to tailor chain orientation and packing structure in liquid crystalline conjugated polymer (LCCP) layers for bio-mimicry of certain structural basis and light-harvesting properties of LHCs is reported. It is found that long-range orientational ordering in an LC phase of poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) copolymer stabilizes a small fraction of randomly-oriented F8BT nanocrystals dispersed in an amorphous matrix of F8BT chains, resembling a self-doped host-guest system whereby excitation energy funneling and photoluminescence quantum efficiencies are enhanced significantly by triggering 3D donor-to-acceptor Förster resonance energy transfer (FRET) and dominant intrachain emission in the nano-crystal acceptor. Further, photoalignment of nematic F8BT layers is combined with LC orientational ordering to fabricate large-area-extended monodomains exhibiting >60% crystallinity and ≈20 nm-long interchain packing order. Remarkably, these monodomains demonstrate strong linearly polarized emission, whilst also promoting a new band-edge absorption species and an extra emissive interchain excited state as compared to the non-aligned films.
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  • 文章类型: Journal Article
    液晶已广泛用于各种应用,如光电器件,生物医学应用,传感器和生物传感器,和包装,在其他人中。液晶聚合物是液晶材料的一种,将其固有特性与聚合物柔性相结合,用于显示器和智能材料的高级应用。例如,液晶聚合物可以作为药物纳米载体,形成立方或六方中间相,可以为控制药物释放量身定做。液晶和液晶聚合物的进一步应用包括制备用于分离过程的膜,如废水处理。此外,这些材料由于其广泛类型的中间相可用作燃料电池或锂电池的离子导电膜。这篇综述旨在提供液晶和液晶聚合物的整体解释和分类。此外,这些材料的巨大潜力依赖于它们广泛的应用,这是由它们独特的属性决定的。此外,这项研究提供了液晶聚合物基膜及其应用的最新进展,特别关注燃料电池。此外,强调了各种液晶应用的未来方向。
    Liquid crystals have been extensively used in various applications, such as optoelectronic devices, biomedical applications, sensors and biosensors, and packaging, among others. Liquid crystal polymers are one type of liquid crystal material, combining their intrinsic properties with polymeric flexibility for advanced applications in displays and smart materials. For instance, liquid crystal polymers can serve as drug nanocarriers, forming cubic or hexagonal mesophases, which can be tailored for controlled drug release. Further applications of liquid crystals and liquid crystal polymers include the preparation of membranes for separation processes, such as wastewater treatment. Furthermore, these materials can be used as ion-conducting membranes for fuel cells or lithium batteries due to their broad types of mesophases. This review aims to provide an overall explanation and classification of liquid crystals and liquid crystal polymers. Furthermore, the great potential of these materials relies on their broad range of applications, which are determined by their unique properties. Moreover, this study provides the latest advances in liquid crystal polymer-based membranes and their applications, focusing especially on fuel cells. Moreover, future directions in the applications of various liquid crystals are highlighted.
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  • 文章类型: Journal Article
    液晶单体(LCM)是新兴的有机污染物,由于其潜在的持久性,毒性,和生物蓄积性。这项研究首先表征了珠江口(PRE)生物中19种LCM的水平和组成,估计了它们的生物累积和营养转移潜力,并确定了优先污染物。LCM通常积累在沉积物中的生物中,所有生物体中的LCM浓度范围为32.35至1367ng/g脂质重量。生物中主要的LCM是联苯和类似物(BA)(76.6%),其次是氰基联苯和类似物(CBA)(15.1%),最少的是氟化联苯和类似物(FBA)(11.2%)。BAs中最丰富的LCM单体,FBA,生物中LCM中的CBA是1-(4-丙基环己基)-4-乙烯基环己烷(15.1%),1-乙氧基-2,3-二氟-4-(4-(4-丙基环己基)环己基)苯(EDPBB,10.1%),和4'-丙氧基-4-联苯甲腈(5.1%),分别。生态位研究表明,PRE食物网由陆生饮食和海洋食物链组成。大多数LCM在陆地饮食和海洋食物链中表现出生物稀释,除了EDPBB和4,4'-双(4-丙基环己基)联苯(BPCHB)。疏水性,LCM的氟取代位置,生物习性可能是影响LCMs生物富集和营养转移的重要因素。1-(丙-1-烯基)-4-(4-丙基环己基)环己烷,和EDPBB被表征为优先污染物。本研究首次报道了LCM的营养转移过程和机制以及PRE中的生物监测。
    Liquid crystal monomers (LCMs) are emerging organic pollutants due to their potential persistence, toxicity, and bioaccumulation. This study first characterized the levels and compositions of 19 LCMs in organisms in the Pearl River Estuary (PRE), estimated their bioaccumulation and trophic transfer potential, and identified priority contaminants. LCMs were generally accumulated in organisms from sediment, and the LCM concentrations in all organisms ranged from 32.35 to 1367 ng/g lipid weight. The main LCMs in organisms were biphenyls and analogues (BAs) (76.6%), followed by cyanobiphenyls and analogues (CBAs) (15.1%), and the least were fluorinated biphenyls and analogues (FBAs) (11.2%). The most abundant LCM monomers of BAs, FBAs, and CBAs in LCMs in organisms were 1-(4-propylcyclohexyl)-4-vinylcyclohexane (15.1%), 1-ethoxy-2,3-difluoro-4-(4-(4-propylcyclohexyl) cyclohexyl) benzene (EDPBB, 10.1%), and 4\'-propoxy-4-biphenylcarbonitrile (5.1%), respectively. The niche studies indicated that the PRE food web was composed of terrestrial-based diet and marine food chains. Most LCMs exhibited biodilution in the terrestrial-based diet and marine food chains, except for EDPBB and 4,4\'-bis(4-propylcyclohexyl) biphenyl (BPCHB). The hydrophobicity, position of fluorine substitution of LCMs, and biological habits may be important factors affecting the bioaccumulation and trophic transfer of LCMs. BPCHB, 1-(prop-1-enyl)-4-(4-propylcyclohexyl) cyclohexane, and EDPBB were characterized as priority contaminants. This study first reports the trophic transfer processes and mechanisms of LCMs and the biomonitoring in PRE.
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  • 文章类型: Journal Article
    3D打印已被引入作为一种新颖的方法,用于设计个性化剂型,并支持具有特殊需求的患者群体,这些患者群体需要额外的帮助来增强药物依从性。在这项研究中,液晶显示器(LCD)被引入用于缓释安非他酮的开发。HCl打印的片剂。印刷水凝胶油墨的优化与盲人或视力受损患者的片剂表面上盲文图案的显示相结合。由于印刷精度高,盲文模式可以由失明患者验证并提供所需的信息。进一步的表征揭示了在光聚合树脂中存在无定形状态的BUP。选择不同分子量的聚(乙二醇)(PEG)-二丙烯酸酯(PEGDA)以及表面活性剂或增溶剂的存在破坏了树脂的光聚合,从而控制BUP溶解速率。小批量放大研究证明了LCD在24分钟内快速打印大量片剂的能力。
    3D printing has been introduced as a novel approach for the design of personalized dosage forms and support patient groups with special needs that require additional assistance for enhanced medication adherence. In this study liquid crystal display (LCD) is introduced for the development of sustained release bupropion.HCl printed tablets. The optimization of printing hydrogel inks was combined with the display of Braille patterns on the tablet surface for blind or visually impaired patients. Due to the high printing accuracy, the Braille patterns could be verified by blind patients and provide the required information. Further characterization revealed the presence of BUP in amorphous state within the photopolymerized resins. The selection of poly(ethylene glycol) (PEG)-diacrylate (PEGDA) of different molecular weights and the presence of surfactants or solubilizers disrupted the resin photopolymerization, thus controlling the BUP dissolution rates. A small batch scale-up study demonstrated the capacity of LCD to print rapidly a notable number of tablets within 24 min.
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  • 文章类型: Journal Article
    海洋贻贝制造坚韧的胶原纤维,称为byssal线,以固定自己。通过分泌液晶(LC)胶原前体(preCos)在几分钟内分别产生线;但是影响线形成的物理和化学参数仍不清楚。这里,我们使用定量偏振光显微镜和透射电子显微镜表征了天然和人工诱导的线的结构各向异性,以阐明线组装的自发vs调节方面,发现PreColLC相形成几百微米的对齐域,但不是本机线程的厘米级对齐。然后,我们探索了机械剪切的假设作用,pH值,通过使用纯化的preCol分泌囊泡的微流体流动聚焦装置的体外组装研究,以及金属离子对线形成的影响。我们的结果为所有三个参数在调节最终产品的结构和性能中的作用提供了明确的证据,这些参数与组织工程应用的胶原支架的制造有关。
    Marine mussels fabricate tough collagenous fibers known as byssal threads to anchor themselves. Threads are produced individually in minutes via secretion of liquid crystalline (LC) collagenous precursors (preCols); yet the physical and chemical parameters influencing thread formation remain unclear. Here, we characterized the structural anisotropy of native and artificially induced threads using quantitative polarized light microscopy and transmission electron microscopy to elucidate spontaneous vs regulated aspects of thread assembly, discovering that preCol LC phases form aligned domains of several hundred microns, but not the cm-level alignment of native threads. We then explored the hypothesized roles of mechanical shear, pH, and metal ions on thread formation through in vitro assembly studies employing a microfluidic flow focusing device using purified preCol secretory vesicles. Our results provide clear evidence for the role of all three parameters in modulating the structure and properties of the final product with relevance for fabrication of collagenous scaffolds for tissue engineering applications.
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  • 文章类型: Journal Article
    氟化液晶单体(FLCM)是一类潜在的新兴的持久性,生物蓄积性,和有毒化合物。人类不可避免地通过食物和环境摄入FLCM。然而,关于FLCM内部暴露生物监测的研究有限。在此,我们根据血清残留水平评估了普通人群中FLCM的估计日摄入量(EDI).第一次,在北京普通人群的314份血清样本中检测到38份FLCM,中位值为132.48ng/g脂质重量(lw)。BDPrB是血清中的主要FLCM。一般居民∑38FLCM的EDI中位数为37.96pg/kgbw/天。城市地区大多数FLCM的残留水平高于郊区(p<0.05)。EFPEB的浓度,EDPrB,EDFPBB,血清中PDTFMTFT与血糖(GLU)呈正相关(r=0.126-0.275,p<0.05)。Logistic回归分析显示,FLCMs与血脂异常呈显著正相关,比值比为2.19;BDPrB与高血糖呈显著正相关(OR:2.48)。总的来说,本研究表明,FLCM在非职业人群中的发生,某些FLCM的暴露可能会导致血糖和血脂水平异常。
    Fluorinated liquid-crystal monomers (FLCMs) are a potential emerging class of persistent, bioaccumulative, and toxic compounds. Humans inevitably ingest FLCMs via food and the environment. However, there are limited studies on internal exposure biomonitoring of FLCMs. Herein, we evaluated the estimated daily intakes (EDIs) of FLCMs in the general population based on serum residue levels. For the first time, 38 FLCMs were detected in 314 serum samples from the general population in Beijing, with a median value of 132.48 ng/g of lipid weight (lw). BDPrB is a predominant FLCM in serum. The median EDI of ∑38FLCMs in the general residents was 37.96 pg/kg bw/day. The residual levels of most FLCMs were higher in urban than in suburban areas (p < 0.05). The concentrations of EFPEB, EDPrB, EDFPBB, and PDTFMTFT in serum showed positive associations with blood glucose (GLU) (r = 0.126-0.275, p < 0.05). Logistic regression analysis showed that FLCMs were significantly positively correlated with dyslipidemia, with an odds ratio of 2.19; BDPrB was significantly positively correlated with hyperglycemia (OR: 2.48). Overall, the present study suggests the occurrence of FLCMs in the nonoccupational population, and the exposure of certain FLCMs may cause abnormal blood glucose and lipid levels.
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  • 文章类型: Journal Article
    我们考虑活动向列相,并使用其流体动力学方程将活动建模为内部场。在系统的哈密顿量中,该场与有限几何中的向列指向矢的相互作用包括在系统的哈密顿量中。基于哈密顿量模型和标准场理论方法,讨论了在这种受限薄膜的边界之间引起的卡西米尔样的力。力取决于我们活动相成分的几何形状和动力学特性,以及锚固条件。对于原则上倾向于沿平面流场对齐的垂直排列的棒状颗粒,延伸活性增强了向列型薄膜中存在的吸引力。随着膜厚度增加,力减小。超过临界厚度,瞬时到弯曲畸变的平面流场设置。接近但低于这种活动引起的不稳定的阈值,力越过零,并在这种所谓的流动不稳定性的临界阈值处排斥性地发散。对于收缩棒,在与上述相同的几何形状中,该结构是稳定的,并且卡西米尔样的力作为膜厚度的函数以指数因子减小。在平面导向器对齐的另一侧,杆状收缩颗粒可以在边界处引起相反的剪切流,从而使板之间的指向矢产生张开变形。在这种配置中,我们获得了与上述力相同的通用过渡前行为。反之亦然,对于这种几何形状中的可延伸棒状颗粒,随着薄膜厚度的增加,导向器的波动变得巨大,并且类似卡西米尔的力再次以指数因子减小。活动场对指向矢的热波动和每个面积的波动引起的卡西米尔力的影响也是通过“半”动力学方法得出的。然而,由于波动模式的数学总和的计算结果不会导致批准的封闭形式。
    We consider an active nematic phase and use hydrodynamical equations of it to model the activity as an internal field. The interaction of this field with the nematic director in a confined geometry is included in the Hamiltonian of the system. Based on this model Hamiltonian and the standard field theoretical approach, the Casimir-like force induced between the boundaries of such a confined film is discussed. The force depends on the geometrical shape and the dynamical character of the constituents of our active phase, as well as the anchoring conditions. For homeotropically aligned rod-like particles which in principle tend to align along a planar flow field, extensile activity enhances the attraction present in a thin nematic film. As the film thickness increases the force reduces. Beyond a critical thickness, a planar flow field instantaneous to a bend distortion sets in. Near but below the threshold of this activity-induced instability, the force crosses zero and repulsively diverges right at the critical threshold of this so-called flow instability. For contractile rods, in the same geometry as above, the structure is stable and the Casimir-like force diminishes by an exponential factor as a function of the film thickness. On the other side for a planar director alignment, rod-like contractile particles can induce opposite shear flows at the boundaries creating a splay distortion for the director between the plates. In this configuration, we obtain the same universal pretransitional behavior for the force as above. Vice versa, for extensile rod-like particles in this geometry, the director fluctuations become massive and the Casimir-like force diminishes again by an exponential factor as the film thickness increases. The effect of the active field on thermal fluctuations of the director and the fluctuation-induced Casimir force per area is derived through a \"semi\"-dynamical approach as well. However, the results of the calculation due to a mathematical sum over the fluctuating modes do not lead to an approved closed form.
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  • 文章类型: Journal Article
    树皮已被证明是一种有效的被动空气采样器,特别是在使用主动采样方法受到限制的情况下。在这项研究中,60个目标液晶单体(LCM;包含10个氰基联苯和类似物(CBAs),13联苯和类似物(BA),从位于珠江三角洲的液晶显示器(LCD)制造商附近收集的34种树皮中分析了37种氟化联苯和类似物(FBA)),华南。树皮中LCM的浓度范围为1400至16000ng/g脂质重量,平均5900ng/g脂质重量。一般来说,在距离LCD制造商5公里的范围内,BA的树皮水平呈指数下降。树皮中LCM的轮廓与先前报道的气相模式相似,表明树皮作为气态LCM的采样器的功效。在现有的关于LCM的环境发生的研究中包含不同的同源物阻碍了水平比较。因此,本研究基于环境监测数据和可公开获取的生产数据建立了优先LCM列表.该列表包括146个LCM,包括63个REACH注册的LCM,这些LCM在任何研究中都没有进行过分析,还有56个属于4种主流LCM。
    Tree bark has been proven as an effective passive air sampler, particularly where access to active sampling methods is limited. In this study, 60 target liquid crystal monomers (LCMs; comprising 10 cyanobiphenyl and analogs (CBAs), 13 biphenyl and analogs (BAs), and 37 fluorinated biphenyl and analogs (FBAs)) were analyzed in 34 tree barks collected from the vicinity of a liquid crystal display (LCD) manufacturer situated in the Pearl River Delta, South China. The concentrations of LCMs in tree barks ranged from 1400 to 16000 ng/g lipid weight, with an average of 5900 ng/g lipid weight. Generally, bark levels of BAs exponentially decreased within 5 km of the LCD manufacturer. The profiles of LCMs in tree barks are similar to previously reported patterns in gaseous phase, suggesting bark\'s efficacy as a sampler for gaseous LCMs. The inclusion of different congeners in existing studies on the environmental occurrence of LCMs has hindered the horizontal comparisons. Therefore, this study established a list of priority LCMs based on environmental monitoring data and the publicly accessible production data. This list comprised 146 LCMs, including 63 REACH registered LCMs that haven\'t been analyzed in any study and 56 belonging to 4 types of mainstream LCMs.
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