Surfaces coated with nanoscale filaments such as silicon nanowires and carbon nanotubes are potentially compelling for high‐performance battery and capacitor electrodes, photovoltaics, electrical interconnects, substrates for engineered cell growth, dry adhesives, and other smart materials. However, many of these applications require a wet environment or involve wet processing during their synthesis. The capillary forces introduced by these wet environments can lead to undesirable aggregation of nanoscale filaments, but control of capillary forces can enable manipulation of the filaments into discrete aggregates and novel hierarchical structures. Recent studies suggest that the elastocapillary self‐assembly of nanofilaments can be a versatile and scalable means to build complex and robust surface architectures. To enable a wider understanding and use of elastocapillary self‐assembly as a fabrication technology, we give an overview of the underlying fundamentals and classify typical implementations and surface designs for nanowires, nanotubes, and nanopillars made from a wide variety of materials. Finally, we discuss exemplary applications and future opportunities to realize new engineered surfaces by the elastocapillary self‐assembly of nanofilaments. 相似文献
Platelets play a fundamental role in thrombus formation and in the pathogenesis of arterial thrombosis. Patterning surfaces for controlled platelet adhesion paves the way for adhesion and activation mechanisms in platelets and detection of platelet functional defects. Here, a new and simple method based on controlled polymerization of 2‐methacryloyloxyethyl phosphorylcholine (MPC) on the surface of styrene‐block‐(ethylene‐co‐butylene)‐block‐styrene (SEBS) is shown. The competition between polymerization and degradation enables platelet adhesion on SEBS to be switched on and off. The adhesive sites of the platelets can be down to single cell level, and the dysfunctional platelets can be quantitatively detected.
A stable superhydrophobic surface have been fabricated with poly(furfuryl alcohol) (PFA)/polytetrafluoroethylene (PTFE) composite coatings on steel substrates by using a facile method. The observation of field emission scanning electron microscopy revealed that the hierarchical microstructures formed on the surfaces are controlled by varying the curing temperature. This method can be easily operated on substrates of steel, therefore is readily developed to other engineering metal substrates such as aluminum, copper, etc. 相似文献
This article describes a simple method for the generation of multicomponent gradient surfaces on self‐assembled monolayers (SAMs) on gold in a precise and predictable manner, by harnessing a chemical reaction on the monolayer, and their applications. A quinone derivative on a monolayer was converted to an amine through spontaneous intramolecular cyclization following first‐order reaction kinetics. An amine gradient on the surface on a scale of centimeters was realized by modulating the exposure time of the quinone‐presenting monolayer to the chemical reagent. The resulting amine was used as a chemical handle to attach various molecules to the monolayer with formation of multicomponent gradient surfaces. The effectiveness of this strategy was verified by cyclic voltammetry (CV), matrix assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry (MS), MS imaging, and contact‐angle measurements. As a practical application, cell adhesion was investigated on RGD/PHSRN peptide/peptide gradient surfaces. Peptide PHSRN was found to synergistically enhance cell adhesion at the position where these two ligands are presented in equal amounts, while these peptide ligands were competitively involved in cell adhesion at other positions. This strategy of generating a gradient may be further expandable to the development of functional gradient surfaces of various molecules and materials, such as DNA, proteins, growth factors, and nanoparticles, and could therefore be useful in many fields of research and practical applications. 相似文献
We investigate the performance of several van der Waals (vdW) functionals at calculating the interactions between benzene and the copper (111) surface, using the local orbital approach in the SIESTA code. We demonstrate the importance of using surface optimized basis sets to calculate properties of pure surfaces, including surface energies and the work function. We quantify the errors created using (3 × 3) supercells to study adsorbate interactions using much larger supercells, and show non‐negligible errors in the binding energies and separation distances. We examine the eight high‐symmetry orientations of benzene on the Cu (111) surface, reporting the binding energies, separation distance, and change in work function. The optimized vdW‐DF(optB88‐vdW) functional provides superior results to the vdW‐DF(revPBE) and vdW‐DF2(rPW86) functionals, and closely matches the experimental and experimentally deduced values. This work demonstrates that local orbital methods using appropriate basis sets combined with a vdW functional can model adsorption between metal surfaces and organic molecules. 相似文献
Functionalization of carbon surfaces was first carried out in electrode pre-treatments under drastic electrolysis conditions. As a result of these treatments, the electrode carbon surfaces were modified without selectivity with a wide variety of oxygenated functional groups. However, this lack of selectivity was partially overshot with some electrochemical strategies of covalent immobilization, such as the reduction of aryldiazonium, arylsulfonium and iodonium salts, the oxidation of amines, alkynes and arylacetates. In a variant of these direct methods, the oxidation of the carbon surfaces in presence of alcohols and alkyltrimethylsilanes has also been developed. This sort of derivatization has opened the possibility to incorporate a wide variety of functional groups according to the desired applications. In the majority of these methods, reactive intermediates such as organic free radicals and carbocations are generated, which react with the sp2 carbon atoms of the surface to produce covalently modified electrodes. In the particular case of the oxidation process of carboxylates, the loss of carbon dioxide is accompanied with the formation of free radicals and by analogy, it is proposed in this work that other organic anions are also susceptible to be oxidized to yield free radicals that could be covalently attached to carbon electrodes. 相似文献