Despite the fact that we live in a 3D world and macroscale engineering is 3D, conventional submillimeter‐scale engineering is inherently 2D. New fabrication and patterning strategies are needed to enable truly 3D‐engineered structures at small size scales. Here, strategies that have been developed over the past two decades that seek to enable such millimeter to nanoscale 3D fabrication and patterning are reviewed. A focus is the strategy of self‐assembly, specifically in a biologically inspired, more deterministic form, known as self‐folding. Self‐folding methods can leverage the strengths of lithography to enable the construction of precisely patterned 3D structures and “smart” components. This self‐assembly approach is compared with other 3D fabrication paradigms, and its advantages and disadvantages are discussed.
Self‐cleaning materials, which are inspired and derived from natural phenomena, have gained significant scientific and commercial interest in the past decades as they are energy‐ and labor‐saving and environmentally friendly. Several technologies are developed to obtain self‐cleaning materials. The combination of superhydrophobic and photocatalytic properties enables the efficient removal of solid particles and organic contaminations, which could reduce or damage the superhydrophobicity. However, the fragility of the nanoscale roughness of the superhydrophobic surface limits its practical application. Here, a hierarchical structure approach combining micro‐ and nanoscale architectures is created to protect the nanoscale surface roughness from mechanical damage. Glass beads of 75 µm are partially embedded into a low‐density polyethylene film. This composite surface is coated with silicone nanofilaments (SNFs) via the droplet‐assisted growth and shaping approach, providing the nanoscale surface roughness as well as the support for the photocatalyst with enlarged surface area. TiO2 nanoparticles, which serve as the photocatalyst, are synthesized in situ on SNFs through a hydrothermal reaction. The self‐cleaning effect is proved using wettability measurements for various liquids, degradation of organic contamination under UV light, and antibacterial tests. The enhanced mechanical durability of the hierarchical structure of the composite material is verified with an abrasion test. 相似文献
In this Review, recent achievements in the multilevel interior‐structured hollow 0D and 1D micro/nanomaterials are presented and categorized. The 0D multilevel interior‐structured micro/nanomaterials are classified into four main interior structural categories that include a macroporous structure, a core‐in‐hollow‐shell structure, a multishell structure, and a multichamber structure. Correspondingly, 1D tubular micro/nanomaterials are of four analogous structures, which are a segmented structure, a wire‐in‐tube structure, a multiwalled structure, and a multichannel structure. Because of the small sizes and complex interior structures, some special synthetic strategies that are different from routine hollowing methods, are proposed to produce these interior structures. Compared with the same‐sized solid or common hollow counterparts, these fantastic multilevel hollow‐structured micro/nanomaterials show a good wealth of outstanding properties that enable them broad applications in catalysis, sensors, Li‐ion batteries, microreactors, biomedicines, and many others. 相似文献
Inspired by the limpet's shell, this study reports an inexpensive and straightforward strategy to create sealed photonic crystals from colloidal hollow microspheres. From the mechanically sealed structure and the periodically isolated air microcavities, the resulting sealed colloidal crystals show enhanced mechanical robustness and an ultrastable photonic band gap. In contrast to the sensitivity and the concomitant tuning capability in conventional opals and inverse opals, the sealed structure repels any liquid, even under high pressure, resulting in ultrastable photonic band gap properties. Moreover, with surface modification, its self‐cleaning ability prevents the deterioration of iridescence resulting from surface pollution. This novel photonic structure shows its potential utility in applications requiring an ultrastable photonic band gap in an extreme environment. This study demonstrates this by photonic crystal lasing at a constant wavelength for a sealed crystal, whether dry in air or submerged in water. 相似文献
This paper addresses the flexural properties of sandwich structures with cellular core materials. Experimental three point bending tests are conducted in order to determine the flexural stiffness and the load‐carrying capacity of these advanced composites. In addition, the significant failure modes after exceeding the load‐carrying capacity are identified. The results of these analyses are compared for sandwich structures containing various core materials. These core materials comprise two aluminium foams, namely M‐Pore® and Alporas®, honeycomb structures and novel metallic hollow sphere structures (MHSS). 相似文献
Dip‐pen nanodisplacement lithography (DNL) is a versatile scanning probe‐based technique that can be employed for fabricating ultrafine 3D polymer brushes under ambient conditions. Many fundamental studies and applications require the large‐area fabrication of 3D structures. However, the fabrication throughput and uniformity are still far from satisfactory. In this work, the molecular displacement mechanism of DNL is elucidated by systematically investigating the synergistic effect of z extension and contact time. The in‐depth understanding of molecular displacement results in the successful achievement of ultrafine control of 3D structures and high‐speed patterning at the same time. Remarkably, one can prepare arbitrary 3D polymer brushes on a large area (1.3 mm × 1.3 mm), with <5% vertical and lateral size variations, and a patterning speed as much as 200‐fold faster than the current state‐of‐the‐art. 相似文献
Self‐cleaning surface coatings is ubiquitous with variety of products today including glass and ceramic tiles, anti‐fogging mirrors, paints, mortars, and concrete. The phenomenon of self‐cleaning is attributed to superhydrophobic surface capable of cleaning itself without any human intervention. The development of superhydrophobic surfaces has been inspired by the desire to mimic the nature viz., water repellent property of lotus leaves and the process is termed as lotus effect. A variety of chemical and physical methods have been reported to fabricate of rough surfaces with low‐surface‐energy coating like, molecular assembly processes, chemical vapor deposition, sol–gel method, and breath‐figure technique (BFT) among others. Among them, BFT offers simple solution processability, robustness, and excellent tunability of surface architecture at different length scales. In this progress report, molecular architectonics of small functional molecules and its application in fabricating selfcleaning materials and surfaces through simple solution processing techniques is described. In these bioinspired approaches, self‐assembly properties of small functional molecules at the molecular level can be controlled by conjugating with basic biomolecules or biomimetic units as functional auxiliaries and adapting suitable experimental techniques. Overall, this progress report demonstrates the progress in molecular architectonics‐based approaches to develop superhydrophobic surfaces with self‐cleaning applications. 相似文献
Since the discovery of graphene in 2004, research on 2D materials has grown rapidly. Compared to their bulk counterparts, 2D atomically thin, layered transition‐metal dichalcogenides (TMDCs or MX2) nanosheets exhibit excellent electronic and optical properties, outstanding mechanical flexibility, and exceptional catalytic performance. As a representative of 2D materials, MX2 holds great promise in many potential applications, especially in energy‐related applications. Here, a brief overview of atomically thin layered MX2 nanosheets applied in energy storage and conversion systems is presented. Firstly, the crystal structures and phases, morphologies, and synthesis methods of MX2 are discussed. Sequentially, the achieved progress on atomically thin MX2 in energy‐related applications (i.e., the hydrogen‐evolution reaction, oxygen‐evolution reaction, CO2 electrochemical reduction, electrochemical capacitors, lithium‐ion batteries, sodium‐ion batteries, and lithium–sulfur batteries) is systematically discussed. Finally, the conclusions and some prospects regarding atomically thin MX2 for applications in the field of energy‐storage systems are provided. 相似文献
Earthworms are able to pass through sticky soil without inducing stains through a self‐forming thick lubricating layer on their rough skins. To mimic this earthworm‐like lubricating capability, an attempt to create a textured structure on the surface of liquid‐releasable polymer coatings by a “breath figure” process is described herein. The resulting coatings exhibit fast and site‐specific release behavior under external triggers such as solid‐based friction. The released oil is then stabilized by the surface texture to form thick lubricating layers, reducing friction and enhancing wear resistance. Moreover, the coatings also exhibit excellent antifouling property in a sticky soil environment. Because the lubricating layer can be regenerated after consumption, the potential of this self‐replenished lubricating mechanism in preparing friction‐reduction, antiwear, and antifouling coatings used in solid‐based environments is therefore envisioned. 相似文献
Macroscopic supramolecular assembly (MSA) represents a new advancement in supramolecular chemistry involving building blocks with sizes beyond tens of micrometers associating through noncovalent interactions. MSA is established as a unique method to fabricate supramolecularly assembled materials by shortening the length scale between bulk materials and building blocks. However, improving the precise alignment during assembly to form orderly assembled structures remains a challenge. Although the pretreatment of building blocks can ameliorate order to a certain degree, defects or mismatching still exists, which limits the practical applications of MSA. Therefore, an iterative poststrategy is proposed, where self‐correction based on dynamic assembly/disassembly is applied to achieve precise, massive, and parallel assembly. The self‐correction process consists of two key steps: the identification of poorly ordered structures and the selective correction of these structures. This study develops a diffusion‐kinetics‐dependent disassembly to well identify the poorly aligned structures and correct these structures through iterations of disassembly/reassembly in a programmed fashion. Finally, a massive and parallel assembly of 100 precise dimers over eight iteration cycles is achieved, thus providing a powerful solution to the problem of processing insensitivity to errors in self‐assembly‐related methods. 相似文献
Oil stain self‐cleaning and anti‐adhesion at the contacting interface between planar surfaces is a worldwide challenge and is rarely explored. Inspired by the low adhesion of Coccinella septempunctata to rough nanoporous substrates, it is attempted to reduce adhesion between the contacting interfaces of polymer composite due to the oil stain by constructing porous structures. A facile method is proposed to fabricate porous polymer composites by adding zeolite microparticles. Zeolite microparticles are used as oil cleaner to build the self‐cleaning system. The surface morphology, the mechanical properties, the anti‐adhesion and lubrication properties of the polymer composites are studied. It is suggested that the porous structure possesses self‐cleaning and high mechanical strength in ambient conditions. In addition, the excellent anti‐adhesion behavior can be realized due to the absorption of oil stain of the porous structure in the composite. The results show that the synergistic interaction of the roughness and the oleophilic properties decrease the adhesion between two planar surfaces under the oil stain condition. The present work provides a new route for the development of anti‐adhesion materials. 相似文献
The VO2‐based smart windows can dynamically and reversibly adjust the indoor solar irradiation to reduce the energy consumption for building glasses. This paper reports the first successful preparation of Mg‐doped VO2@ZrO2 core−shell nanocrystals with promoted thermochromic performance as well as tunable appearance and wettability. The achieved combination of Tlum of 52.4% and ∆Tsol of 7.1% is comparable to the best‐reported results of VO2‐based core−shell rod structures. The thickness of ZrO2 shell is tunable between 3 and 14 nm, resulting in a slightly hydrophobic surface and a slight color change toward blue‐green and brighter produced films. The preparation method based on hydrothermal and UV‐curing methods is facile. This work may inspire future development of VO2 synthesis, their structure−property, and the application the thermochromic films for energy‐saving purposes in buildings or automobiles. 相似文献
A self‐templated strategy is developed to fabricate hierarchical TiO2/SnO2 hollow spheres coated with graphitized carbon (HTSO/GC‐HSs) by combined sol–gel processes with hydrothermal treatment and calcination. The as‐prepared mesoporous HTSO/GC‐HSs present an approximate yolk‐double–shell structure, with high specific area and small nanocrystals of TiO2 and SnO2, and thus exhibit superior electrochemical reactivity and stability when used as anode materials for Li‐ion batteries. A high reversible specific capacity of about 310 mAh g?1 at a high current density of 5 A g?1 can be achieved over 500 cycles indicating very good cycle stability and rate performance. 相似文献
Textured organogel films showing thermoresponsive (TR)‐syneretic and optical behaviors are fabricated based on soft lithography, using micro/nanostructured master moulds, of polydimethylsiloxane infused with polymethylphenylsiloxane (PMPS) as a lubricating oil. The critical syneretic temperature (CST) of the organogels can be arbitrarily tuned in the range of −15–50 °C by varying the volume of PMPS. Below the CST, the oil is spontaneously released from the inside of the gel matrices to the topmost surface, and vice versa, and it gradually returns back to the matrices above the CST. In the lubricated state, the textured TR‐organogel film surfaces exhibit excellent dynamic hydrophobicity and icephobicity, i.e., ice can be easily removed from the surface without any additional force. Simultaneously, optical properties derived from surface micro/nanotextures, such as diffraction and antireflection, respectively, are clearly observed above the CST and disappear below the CST, because the surface textures are buried by the released PMPS. These unusual TR‐surface functionalities are found to be repeatable/switchable for several tens of times. 相似文献
Thin-film Bragg stacks exhibiting structural color have been fabricated by a layer-by-layer (LbL) deposition process involving the sequential adsorption of nanoparticles and polymers. High- and low-refractive-index regions of quarter-wave stacks were generated by calcining LbL-assembled multilayers containing TiO(2) and SiO(2) nanoparticles, respectively. The physical attributes of each region were characterized by a recently developed ellipsometric method. The structural color characteristics of the resultant nanoporous Bragg stacks could be precisely tuned in the visible region by varying the number of stacks and the thickness of the high- and low-refractive-index stacks. These Bragg stacks also exhibited potentially useful superhydrophilicity and self-cleaning properties. 相似文献
