共查询到20条相似文献，搜索用时 24 毫秒
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Billy J. Williams-Noonan Ketav Kulkarni Nevena Todorova Matteo Franceschi Christopher Wilde Mark P. Del Borgo Louise C. Serpell Marie-Isabel Aguilar Irene Yarovsky 《Advanced materials (Deerfield Beach, Fla.)》2024,36(24):2311103
β-Peptides have great potential as novel biomaterials and therapeutic agents, due to their unique ability to self-assemble into low dimensional nanostructures, and their resistance to enzymatic degradation in vivo. However, the self-assembly mechanisms of β-peptides, which possess increased flexibility due to the extra backbone methylene groups present within the constituent β-amino acids, are not well understood due to inherent difficulties of observing their bottom-up growth pathway experimentally. A computational approach is presented for the bottom-up modelling of the self-assembled lipidated β3-peptides, from monomers, to oligomers, to supramolecular low-dimensional nanostructures, in all-atom detail. The approach is applied to elucidate the self-assembly mechanisms of recently discovered, distinct structural morphologies of low dimensional nanomaterials, assembled from lipidated β3-peptide monomers. The resultant structures of the nanobelts and the twisted fibrils are stable throughout subsequent unrestrained all-atom molecular dynamics simulations, and these assemblies display good agreement with the structural features obtained from X-ray fiber diffraction and atomic force microscopy data. This is the first reported, fully-atomistic model of a lipidated β3-peptide-based nanomaterial, and the computational approach developed here, in combination with experimental fiber diffraction analysis and atomic force microscopy, will be useful in elucidating the atomic scale structure of self-assembled peptide-based and other supramolecular nanomaterials. 相似文献
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目的 研究纳米银团簇的运动机理及连接料对团聚的影响。方法 以环氧树脂为导电银浆连接料,分别建立不同环氧树脂含量的纳米银团簇和环氧树脂模型,模拟不同环氧树脂含量下纳米银团簇的动力学平衡状况。结果 纳米银团簇在常温下极易发生团聚,加入环氧树脂后,系统能量虽然增大,但银团簇的运动活性明显降低;环氧树脂吸附于银团簇表面,阻止了银团簇间的团聚,银团簇的团聚倾向和银原子的运动活性随环氧树脂含量的升高逐渐降低;模拟结果显示,当环氧树脂质量分数增大至33%时,环氧树脂可起到防止银团簇团聚的效果。结论 在导电银浆中,纳米银团簇在常温下易团聚且受环氧树脂的影响较大。 相似文献
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减轻蒸汽冷凝水对输运管线的腐蚀有利于实现其净化并含能直接回用。本研究通过饱和溶液法制备以β-环糊精(β-CyD)为主体,肉桂醛(CA)为客体的超分子缓蚀剂(CDCA)。核磁共振氢谱结果显示CA可从β-CyD的宽端口或窄端口进入疏水空腔,从宽端口组装的产物总能量低;相溶解度曲线表明CDCA中主、客体的组装计量比为1∶1,结合常数达786 mol-1。将CDCA引入冷凝水回收系统可降低水体的全铁含量;现场监测显示,加入CDCA后,冷凝水中的全铁含量显著降低并维持在50~70 μg·L-1。动态失重结果表明CDCA可有效抑制碳钢在冷凝水中的腐蚀,并阻滞腐蚀产物向水体扩散,当温度为298 K,CDCA的添加浓度为150 mg·L-1时,碳钢在水体中的缓蚀率达94.1%。动电位极化结果表明CDCA能同时抑制碳钢在冷凝水中阴、阳极的腐蚀过程,属于阳极抑制为主的混合型缓蚀剂。电化学阻抗谱与线性极化电阻的结果均表明CDCA可显著增大碳钢在冷凝水中腐蚀的极化电阻。表面分析显示经CDCA处理后的碳钢试样仅检测到客体CA的价键信息,因此可推断仅CA在金属表面吸附成膜。理论模拟验证了该推论并指明CA以平行取向吸附于碳钢表面。 相似文献
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聚合物基导电复合材料研究进展 总被引：20，自引：0，他引：20
本文介绍了聚合物基导电复合材料的种类、用途及导电机理。并对碳系填料填充聚合物基导电复合材料及金属系填料填充聚合物基导电复合材料的研究进展进行了综述 ,最后展望了聚合物基导电复合材料的发展趋势。 相似文献
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Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet （UV） light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable promising solution for their long-term irradiations. superhydrophobic surfaces provides a service under UV or strong solar light 相似文献
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柔性可穿戴电子器件的研制是未来科技发展的方向之一,柔性导电材料是可穿戴电子器件的重要支撑材料。由于聚合物具有优异的柔性,由聚合物基导电复合材料制备柔性导体是一种重要的途径和方式。文中从制备和表征方法方面归纳了聚合物基柔性导电复合材料的研究进展,重点阐述了实现柔性导体的关键因素,即聚合物优异高弹性的保持和可拉伸的稳定的导电网络的实现,详细介绍了简易地利用高弹性基体和纳米填料的直接共混法和目前应用较多的结构可拉伸导体的设计与制备,并总结了目前研究中存在的问题。 相似文献
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Zongshang Li;Jihyuk Yang;Fengke Sun;Kam-Hung Low;Wenming Tian;Shengye Jin;Ji Tae Kim;Chi-Ming Che;Qingyun Wan; 《Advanced materials (Deerfield Beach, Fla.)》2024,36(23):2402725
Creating hierarchical molecular block heterostructures, with the control over size, shape, optical, and electronic properties of each nanostructured building block can help develop functional applications, such as information storage, nanowire spectrometry, and photonic computing. However, achieving precise control over the position of molecular assemblies, and the dynamics of excitons in each block, remains a challenge. In the present work, the first fabrication of molecular heterostructures with the control of exciton dynamics in each block, is demonstrated. Additionally, these heterostructures are printable and can be precisely positioned using Direct Ink Writing-based (DIW) 3D printing technique, resulting in programable patterns. Singlet excitons with emission lifetimes on nanosecond or microsecond timescales and triplet excitons with emission lifetimes on millisecond timescales appear simultaneously in different building blocks, with an efficient energy transfer process in the heterojunction. These organic materials also exhibit stimuli-responsive emission by changing the power or wavelength of the excitation laser. Potential applications of these organic heterostructures in integrated photonics, where the versatility of fluorescence, phosphorescence, efficient energy transfer, printability, and stimulus sensitivity co-exist in a single nanowire, are foreseen. 相似文献
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Gelation: Three‐Dimensional Shape Engineered,Interfacial Gelation of Reduced Graphene Oxide for High Rate,Large Capacity Supercapacitors (Adv. Mater. 4/2014) 
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下载免费PDF全文 Uday Narayan Maiti Joonwon Lim Kyung Eun Lee Won Joon Lee Sang Ouk Kim 《Advanced materials (Deerfield Beach, Fla.)》2014,26(4):505-505
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炭黑填充型导电复合材料的压阻计算模型及实验验证 总被引：3，自引：2，他引：1
为研究新型传感器材料,在通用有效介质理论的基础上,提出了炭黑填充型导电复合材料的压阻特性数学计算模型,定量地得出炭黑颗粒的基本特征参数、体积分数和聚合物基体的弹性模量在复合材料压阻规律中的影响。分别以硅橡胶和高密度聚乙烯为基体相,三种不同粒径的炭黑为导电相,制备了炭黑填充型复合材料,对计算模型进行了实验验证。在炭黑颗粒分布均匀、炭黑体积分数在渗流阈值附近和外加压力≤2 MPa等三个边界条件下,数学计算模型与实验结果基本吻合,且压力-电阻变化规律一致。 相似文献
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本文系统研究了两步pH调节B型明胶水溶胶合成磷酸钙纳米晶多孔微球。实验采用了"两步pH调节法"对80℃明胶-磷酸钠水溶胶的pH进行预调节:用酸对水溶胶的pH值从5.6调节到3.0,再用碱调节到4.0,然后向水溶胶中滴加钙盐溶液合成磷酸钙。研究中也按常规的一步pH调节方式用酸将水溶胶的pH值从5.6调节到4.0,然后合成磷酸钙作为对照实验。结果表明,两步pH调节法使得磷酸钙纳米晶发生有序自组装形成多孔性微球,而一步pH调节法则出现纳米晶无序聚集和生长。同时,按上述两步pH调节法还可以制备微量元素锶掺杂的多孔性微球。以上研究结果对于仿生溶液介质pH预调节方法影响磷酸钙纳米晶聚集、生长具有重要启示,同时这种多孔性磷酸钙微球在骨修复、缓释给药、细胞支架以及生物分离等方面都具有潜在应用价值。 相似文献
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Lin Lin Siyao Liu Sirui Fu Shuangmei Zhang Hua Deng Qiang Fu 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(21):3620-3629
Stretchable conductors, which can keep their excellent electrical conductivity while highly stretched, have been investigated extensively due to their wide range of applications in flexible and stretchable electronics, wearable displays, etc.; however, their preparation is often complicated and expensive. Herein, an efficient method to prepare high performance stretchable conductors through morphological control of conductive networks formed with carbon nanotubes (CNTs) in an elastomer matrix is reported. It is observed that an interface‐mediated method could be used to align randomly oriented filler during stretching and to induce buckling of CNTs during relaxation. Further morphological studies indicate the possible formation of a wavy CNT structure induced by cyclic pre‐straining. Subsequent thermal annealing is observed to collapse the oriented network and improve the local contacts between conductive networks. Through such a simple procedure, a conductivity of nearly 1000 S m?1 and a stretchability of 200% can be achieved for composites containing 20 wt% CNTs. CNTs are observed to buckle over a large area in polymer bulk, and the combination of pre‐straining and thermal annealing modifies the conductive network in the elastomer matrix. As a general method, this could be used for easy fabrication of high‐performance stretchable conductors for arbitrary‐shaped objects on a large scale. 相似文献
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The interfacial strength between carbon fiber and phenolic resin is studied using molecular dynamics simulations to demonstrate that carbon fiber-reinforced carbon matrix composites (C/C composites) have improved tensile strength. Simulations are performed using two carbon fiber models, one of which has only carbon atoms and the other has carbon atoms and some fluorinated carbon groups. The carbon fiber models are regarded as two-layer graphite, and the phenolic resin model is treated as cross-linked structures. All force field parameters are based on the Dreiding force field. The tensile stress and interfacial fracture energy are calculated for the estimation of the interfacial strength. The results show that the model including the fluorinated carbon groups has lower interfacial strength than the model having only carbon atoms, up to a certain coating ratio of fluorinated carbon groups. Similarly, within the limits of the coating ratio, the interfacial fracture energy of the fluorinated carbon fiber model is lower than that of carbon fiber model having only carbon atoms. 相似文献
