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1.
A versatile colloidal templating strategy to fabricate hierarchically structured inverse opals is investigated. A sequence of infiltration and pyrolysis steps provides access to a range of material combinations such as SiO2, Al2O3, or TiO2. The experimental results also document the feasibility of this method to fabricate porous polymer films with a double periodic pore lattice. 相似文献
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Gaigai Duan Shaohua Jiang Valérie Jérôme Joachim H. Wendorff Amir Fathi Jaqueline Uhm Volker Altstädt Markus Herling Josef Breu Ruth Freitag Seema Agarwal Andreas Greiner 《Advanced functional materials》2015,25(19):2850-2856
Ultralight polymer sponges are prepared by freeze‐drying of dispersions of short electrospun fibers. In contrast to many other highly porous materials, these sponges show extremely low densities (<3 mg cm?3) in combination with low specific surface areas. The resulting hierarchical pore structure of the sponges gives basis for soft and reversibly compressible materials and to hydrophobic behavior in combination with excellent uptake for hydrophobic liquids. Owing to their large porosity, cell culturing is successful after hydrophilic modification of the sponges. 相似文献
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Lukas Helmbrecht Melissa Tan Ruslan Rhrich Marloes H. Bistervels Bruno Ortiz Kessels A. Femius Koenderink Bart Kahr Willem L. Noorduin 《Advanced functional materials》2020,30(26)
Bottom‐up assembly can organize simple building blocks into complex architectures for light manipulation. The optical properties of self‐assembled polycrystalline barium carbonate/silica double helices are studied using fluorescent Fourier and Mueller matrix microscopy. Helices doped with fluorescein direct light emission along the long axis of the structure. Furthermore, light transmission measured normal and parallel to the long axis exhibits twist sense‐specific circular retardance and waveguiding, respectively, although the measurements suffer from depolarization. The helices thus integrate highly directional emission with enantiomorph‐specific polarization. This optical response emerges from the arrangement of nanoscopic mineral crystallites in the microscopic helix, and demonstrates how bottom‐up assembly can achieve ordering across multiple length scales to form complex functional materials. 相似文献
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Wei Zhang Kenji Ochi Michiya Fujiki Masanobu Naito Masaaki Ishikawa Kei‐ichi Kaneto Wataru Takashima Akinori Saeki Shu Seki 《Advanced functional materials》2010,20(22):3941-3947
In this paper a simple, casting solution technique for the preparation of two‐dimensional (2D) arrays of very‐high molecular weight (MW) 1D‐Pc supramolecular inorganic polymers is described. The soluble fluoroaluminium tetra‐tert‐butylphthalocyanine (ttbPcAlF) is synthesized and characterized, which can be self‐assembled to form 2D arrays of very‐high‐MW 1D‐Pc supramolecular inorganic polymers. High‐resolution transmission electron microscopy (HRTEM) demonstrates that the 1D‐ttbPcAlF, having a cofacial ring spacing of ～0.36 nm and an interchain distance of ～1.7 nm, self‐assembles into 2D‐nanosheets (～140 nm in length, ～20 nm in width, and equivalent to MW of 3.2 × 105 g mol?1). The film cast from a 1,2‐dichloroethane (DCE) solution shows a minimum hole‐mobility of ～0.3 cm2 V?1 s?1 at room temperature by flash‐photolysis time‐resolved microwave conductivity (TRMC) measurements and a fairly high dark dc‐conductivity of ～1 × 10?3 S cm?1. 相似文献
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The small‐sized molecules that have been developed from single hydrophobic amino acids (Phe, Trp, Tyr and Leu) by suitably protecting the –NH2 and –CO2H groups generate diverse nanoscopic structures – such as nanorods, nanofibrils, nanotubes, and nanovesicles – depending upon the protection parameters and solvent polarity. The vesicular structures get disrupted in the presence of various salts, such as KCl, CaCl2, (NH4)2SO4 and N(n‐Bu)4Br. Insertion of unnatural (o/m/p)‐aminobenzoic acids as a protecting group and the lack of conventional peptide bonds in the molecules give the nanostructures proteolytic stability. The nanostructures also show significant thermal stability along with a morphological transformation upon heat treatment. Our in vitro studies reveal that the addition of micromolar concentration “curcumin” significantly reduces the formation of amyloid‐like fibrils. These diverse nanostructures are used as a template for fabricating silver nanoparticles on their outer surfaces as well as in the inner part, followed by calcination in air which helps to obtain a 1D silver nanostructure. Furthermore, the nanovesicles are observed to encapsulate a potent drug (curcumin) and other biologically important molecules, which could be released through salt‐triggered disruption of vesicles. 相似文献
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Nanoparticle assembly and colloidal processing are two techniques with the goal to fabricate materials and devices from preformed particles. While colloidal processing has become an integral part of ceramic processing, nanoparticle assembly is still mainly limited to academic interests. It typically starts with the precise synthesis of building blocks, which are generally not only considerably smaller than those used for colloidal processing, but also better defined in terms of size, shape, and size distribution. Their arrangement into 1D, 2D, and 3D architectures is performed with great accuracy well beyond what is achieved by colloidal processing. At the same time, the final assembly is not sintered such that the intrinsic, nanospecific properties of the initial building blocks are preserved or even lead to collective behavior. However, in contrast to colloidal processing the structures accessible by nanoparticle assembly are often limited to a small length scale. The review presents selected examples of nanoparticle assembly and colloidal processing with the goal to reveal the capabilities of these two techniques to fabricate novel materials from preformed building blocks, and also to demonstrate the immense opportunities that would arise if the two methods could be combined with each other. 相似文献
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Seung Goo Lee Ho Sun Lim Dong Yun Lee Donghoon Kwak Kilwon Cho 《Advanced functional materials》2013,23(5):526-526
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Seung Goo Lee Ho Sun Lim Dong Yun Lee Donghoon Kwak Kilwon Cho 《Advanced functional materials》2013,23(5):547-553
Rice leaves can directionally shed water droplets along the longitudinal direction of the leaf. Inspired by the hierarchical structures of rice leaf surfaces, synthetic rice leaf‐like wavy surfaces are fabricated that display a tunable anisotropic wettability by using electrostatic layer‐by‐layer assembly on anisotropic microwrinkled substrates. The nanoscale roughness of the rice leaf‐like surfaces is controlled to yield tunable anisotropic wettability and hydrophobic properties that transitioned between the anisotropic/pinned, anisotropic/rollable, and isotropic/rollable water droplet behavior states. These remarkable changes result from discontinuities in the three‐phase (solid–liquid–gas) contact line due to the presence of air trapped beneath the liquid, which is controlled by the surface roughness of the hierarchical nanostructures. The mechanism underlying the directional water‐rolling properties of the rice leaf‐like surfaces provides insight into the development of a range of innovative applications that require control over directional flow. 相似文献
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Hakan Ceylan Mustafa Urel Turan S. Erkal Ayse B. Tekinay Aykutlu Dana Mustafa O. Guler 《Advanced functional materials》2013,23(16):2081-2090
A general drawback of supramolecular peptide networks is their weak mechanical properties. In order to overcome a similar challenge, mussels have adapted to a pH‐dependent iron complexation strategy for adhesion and curing. This strategy also provides successful stiffening and self‐healing properties. The present study is inspired by the mussel curing strategy to establish iron cross‐link points in self‐assembled peptide networks. The impact of peptide‐iron complexation on the morphology and secondary structure of the supramolecular nanofibers is characterized by scanning electron microscopy, circular dichroism and Fourier transform infrared spectroscopy. Mechanical properties of the cross‐linked network are probed by small angle oscillatory rheology and nanoindentation by atomic force microscopy. It is shown that iron complexation has no influence on self‐assembly and β‐sheet‐driven elongation of the nanofibers. On the other hand, the organic‐inorganic hybrid network of iron cross‐linked nanofibers demonstrates strong mechanical properties comparable to that of covalently cross‐linked network. Strikingly, iron cross‐linking does not inhibit intrinsic reversibility of supramolecular peptide polymers into disassembled building blocks and the self‐healing ability upon high shear load. The strategy described here could be extended to improve mechanical properties of a wide range of supramolecular polymer networks. 相似文献
11.
Tae Woo Kim In Young Kim Tae Sung Jung Chang Hyun Ko Seong‐Ju Hwang 《Advanced functional materials》2013,23(35):4377-4385
A new type of efficient CO2 absorbent with improved thermal stability is synthesized via self‐assembly between 2D inorganic nanosheets and two kinds of 0D inorganic nanoclusters. In these self‐assembled nanohybrids, the nanoclusters of CdO and Cr2O3 are commonly interstratified with layered titanate nanosheets, leading to the formation of highly microporous pillared structure with increased basicity of pore wall. The co‐pillaring of basic CdO with Cr2O3 is fairly effective at increasing a proportion of micropores and reactivity for CO2 molecules and at improving the thermal stability of the resulting porous structure. Of prime importance is that the present inorganic‐pillared nanohybrids show highly efficient CO2 adsorption capacity, which is much superior to those of many other absorbents and compatible to those of CO2 adsorbing metal?organic framework (MOF) compounds. Taking into account an excellent thermal stability of the present nanohybrids, these materials are very promising CO2 adsorbents usable at elevated temperature. This is the first example of efficient CO2 adsorbent from pillared materials. The co‐pillaring of basic metal oxide nanoclusters employed in this study can provide a very powerful way of developing thermally stable CO2 adsorbents from many known pillared systems. 相似文献
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Yantao Shi Chun Zhan Liduo Wang Beibei Ma Rui Gao Yifeng Zhu Yong Qiu 《Advanced functional materials》2010,20(3):437-444
In this paper, a novel hierarchically structured ZnO photoanode for use in quasi‐solid state dye‐sensitized solar cells (DSCs) is presented. The film is composed of polydisperse spindle‐shaped ZnO particles that are prepared through direct precipitation of zinc acetate in aqueous solution. Without additional pore‐forming agents, the microporous structure is well constructed through the packing of polydisperse ZnO particles. In the film, small ZnO particles are able to improve interparticle connectivity and offer a large internal surface area for sufficient dye‐adsorption; on the other hand, particles of larger size can enhance the occurrence of light‐scattering and introduce micropores for the permeation of quasi‐solid state electrolytes. Meanwhile, morphologies, particle size, and specific areas of the products are controlled by altering the reactant concentration and synthetic temperature. Combined with a highly viscous polymer gel electrolyte, a device based on this ZnO photoanode shows high conversion efficiencies, 4.0% and 7.0%, under 100 and 30 mW cm?2 illumination, respectively. Finally, the unsealed device is demonstrated to remain above 90% of its initial conversion efficiency after 7 days, showing excellent stability. 相似文献
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Bayu Atmaja Bertrand H. Lui Yuhua Hu Stayce E. Beck Curtis W. Frank Jennifer R. Cochran 《Advanced functional materials》2010,20(23):4091-4097
A highly tunable quantum dot (QD)–polypeptide hybrid assembly system with potential uses for both molecular imaging and delivery of biomolecular cargo to cancer cells is reported. The tunability of the assembly system, its application for imaging cancer cells, and its ability to carry a biomolecule are demonstrated. The assemblies are formed through the self‐assembly of carboxyl‐functionalized QDs and poly(diethylene glycol‐L ‐lysine)‐poly(L ‐lysine) (PEGLL‐PLL) diblock copolypeptide molecules, and they are modified with peptide ligands containing a cyclic arginine‐glycine‐aspartate [c(RGD)] motif that has affinity for αvβ3 and αvβ5 integrins overexpressed on the tumor vasculature. To illustrate the tunability of the QD‐polypeptide assembly system, it is shown that binding to U87MG glioblastoma cells can be modulated and optimized by changing either the conditions under which the assemblies are formed or the relative lengths of the PEGLL and PLL blocks in the PEGLL‐PLL molecules. The optimized c(RGD)‐modified assemblies bind integrin receptors on U87MG cells and are endocytosed, as demonstrated by flow cytometry and live‐cell imaging. Binding specificity is confirmed by competition with an excess of free c(RGD) peptide. Finally, it is shown that the QD–polypeptide assemblies can be loaded with fluorescently labeled ovalbumin, as a proof‐of‐concept for their potential use in biomolecule delivery. 相似文献
15.
Elina Ploshnik Karol M. Langner Amit Halevi Meirav Ben‐Lulu Axel H. E. Müller Johannes G. E. M. Fraaije G. J. Agur Sevink Roy Shenhar 《Advanced functional materials》2013,23(34):4215-4226
Tailoring the size and surface chemistry of nanoparticles allows one to control their position in a block copolymer, but this is usually limited to one‐dimensional distribution across domains. Here, the hierarchical assembly of poly(ethylene oxide)‐stabilized gold nanoparticles (Au‐PEO) into hexagonally packed clusters inside mesostructured ultrathin films of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) is described. A close examination of the structural evolution at different nanoparticle filling fractions and PEO ligand molecular weights suggests that the mechanism leading to this structure‐within‐structure is the existence of two phase separation processes operating on different time scales. The length of the PEO ligand is shown to influence not only the interparticle distances but also the phase separation processes. These conclusions are supported by novel mesoscopic simulations, which provide additional insight into the kinetic and thermodynamic factors that are responsible for this behavior. 相似文献
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Matthew J. Glassman Jacqueline Chan Bradley D. Olsen 《Advanced functional materials》2013,23(9):1224-1224
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Although control over the domain orientation and long‐range order of block copolymer nanostructures self‐assembled in thin films has been achieved using various directed self‐assembly techniques, more challenging but equally important for many lithographic applications is the ability to precisely control the shape of the interface between domains. Here, a novel layer‐by‐layer approach is reported for controlling the interface profile of block copolymer nanostructures and the application of an undercut sidewall profile for an enhanced metal lift‐off process for pattern transfer is demonstrated. Bilayer films of lamellar‐forming poly(styrene‐block‐methyl methacrylate) are assembled and thermally cross‐linked on wafer substrates in a layer‐by‐layer process. The top layer, while being directed to self‐assemble on the lamellae of the underlying layer, has a tunable composition and polystyrene domain width independent of that of the bottom layer. Undercut or negative sidewall profiles in the PS nanostructures are proven to provide better templates for the lift‐off of Au nanowires by achieving complete and defect‐free pattern transfer more than three times faster than comparable systems with vertical sidewall profiles. More broadly, the layer‐by‐layer approach presented here provides a pathway to achieving sophisticated interface profiles and user‐defined 3D block copolymer nanostructures in thin films. 相似文献
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Matthew J. Glassman Jacqueline Chan Bradley D. Olsen 《Advanced functional materials》2013,23(9):1182-1193
Shear thinning hydrogels are promising materials that exhibit rapid self‐healing following the cessation of shear, making them attractive for applications including injectable biomaterials. Here, self‐assembly is demonstrated as a strategy to introduce a reinforcing network within shear thinning artificially engineered protein gels, enabling a responsive transition from an injectable state at low temperatures with a low yield stress to a stiffened state at physiological temperatures with resistance to shear thinning, higher toughness, and reduced erosion rates and creep compliance. Protein‐polymer triblock copolymers capable of the responsive self‐assembly of two orthogonal networks are synthesized. Midblock association forms a shear‐thinning network, while endblock aggregation at elevated temperatures introduces a second, independent physical network into the protein hydrogel. These reversible crosslinks introduce extremely long relaxation times and lead to a five‐fold increase in the elastic modulus, significantly larger than is expected from transient network theory. Thermoresponsive reinforcement reduces the high temperature creep compliance by over four orders of magnitude, decreases the erosion rate by at least a factor of five, and increases the yield stress by up to a factor of seven. Combined with the demonstrated potential of shear thinning artificial protein hydrogels for various uses, this reinforcement mechanism broadens the range of applications that can be addressed with shear‐thinning physical gels. 相似文献
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Amir Fahmi Torsten Pietsch Maria Bryszewska José Carlos Rodríguez‐Cabello Aneta Koceva‐Chyla Francisco Javier Arias Matilde Alonso Rodrigo Nabil Gindy 《Advanced functional materials》2010,20(6):1011-1018
The design and synthesis of nanostructured functional hybrid biomaterials are essential for the next generation of advanced diagnostics and the treatment of disease. A simple route to fabricate semiconductor nanofibers by self‐assembled, elastin‐like polymer (ELP)‐templated semiconductor nanoparticles is reported. Core–shell nanostructures of CdSe nanoparticles with a shell of ELPs are used as building blocks to fabricate functional one‐dimensional (1D) nanostructures. The CdSe particles are generated in situ within the ELP matrix at room temperature. The ELP controls the size and the size‐distribution of the CdSe nanoparticles in an aqueous medium and simultaneously directs the self‐assembly of core–shell building blocks into fibril architectures. It was found that the self‐assembly of core–shell building blocks into nanofibers is strongly dependent on the pH value of the medium. Results of cytotoxicity and antiproliferation of the CdSe‐ELP nanofibers demonstrate that the CdSe‐ELP does not exhibit any toxicity towards B14 cells. Moreover, these are found to be markedly capable of crossing the cell membrane of B14. In contrast, unmodified CdSe nanoparticles with ELPs cause a strong toxic response and reduction in the cell proliferation. This concept is valid for the fabrication of a variety of metallic and semiconductor 1D‐architectures. Therefore, it is believed that these could be used not only for biomedical purposes but for application in a wide range of advanced miniaturized devices. 相似文献