Microcontact Printing Research Articles

A model study on controlling dealloying corrosion attack by lateral modification of surfactant inhibitors

Detrimental corrosion is an ever-concerning challenge for metals and alloys. One possible remedy is to apply organic corrosion inhibitors. Despite progress in molecular assembly and inhibitor research, better mechanistic insight on the molecular level is needed. Here we report on the behavior of well-defined artificial molecular interfaces created by micro-contact printing of thiol-inhibitor molecules and subsequent backfilling. The obtained heterogeneity and defects trigger localized dealloying-corrosion of well-defined Cu3Au surfaces. The stability of applied inhibitor molecules depends on alloy surface morphology and on intermolecular forces of the molecular layers. On extended terraces, dealloying preferentially starts at the boundary between areas composed of the two different chain-length inhibitor molecules. Inside of the areas hardly any nucleation of initial pits is visible. Step density strongly influences the morphology of the dealloying attack, while film heterogeneity avoids cracking and controls molecular-scale corrosion attack. The presented surface-science approach, moreover, will ultimately allow to verify the acting mechanisms of inhibitor-cocktails to develop recipes to stabilize metallic alloy surfaces.

Applications of Hybrid Polymers Generated from Living Anionic Ring Opening Polymerization.

Increasingly precise control of polymer architectures generated by “Living” Anionic Ring-Opening Polymerization (Living AROP) is leading to a broad range of commercial advanced material applications, particularly in the area of siloxane macromers. While academic reports on such materials remain sparse, a significant portion of the global population interacts with them on a daily basis—in applications including medical devices, microelectronics, food packaging, synthetic leather, release coatings, and pigment dispersions. The primary driver of this increased utilization of siloxane macromers is their ability to incorporate the properties of silicones into organic structures in a balanced manner. Compared to organic polymers, the differentiating properties of silicones—low Tg, hydrophobicity, low surface energy, and high free molal space—logically lend themselves to applications in which low modulus, release, permeability to oxygen and moisture, and tactile interaction are desired. However, their mechanical, structural and processing properties have until recently precluded practical applications. This review presents applications of “Living” AROP derived polymers from the perspective of historical technology development. Applications in which products are produced on a commercial scale—defined as not only offered for sale, but sold on a recurrent basis—are emphasized. Hybrid polymers with intriguing nanoscale morphology and potential applications in photoresist, microcontact printing, biomimetic soft materials, and liquid crystals are also discussed. Previously unreported work by the authors is provided in the context of this review.

Solid-Phase Microcontact Printing for Precise Patterning of Rough Surfaces: Using Polymer-Tethered Elastomeric Stamps for the Transfer of Reactive Silanes.

We present a microcontact printing (μCP) routine suitable to introduce defined (sub-) microscale patterns on surface substrates exhibiting a high capillary activity and receptive to a silane-based chemistry. This is achieved by transferring functional trivalent alkoxysilanes, such as (3-aminopropyl)-triethoxysilane (APTES) as a low-molecular weight ink via reversible covalent attachment to polymer brushes grafted from elastomeric polydimethylsiloxane (PDMS) stamps. The brushes consist of poly{N-[tris(hydroxymethyl)-methyl]acrylamide} (PTrisAAm) synthesized by reversible addition–fragmentation chain-transfer (RAFT)-polymerization and used for immobilization of the alkoxysilane-based ink by substituting the alkoxy moieties with polymer-bound hydroxyl groups. Upon physical contact of the silane-carrying polymers with surfaces, the conjugated silane transfers to the substrate, thus completely suppressing ink-flow and, in turn, maximizing printing accuracy even for otherwise not addressable substrate topographies. We provide a concisely conducted investigation on polymer brush formation using atomic force microscopy (AFM) and ellipsometry as well as ink immobilization utilizing two-dimensional proton nuclear Overhauser enhancement spectroscopy (1H–1H-NOESY-NMR). We analyze the μCP process by printing onto Si-wafers and show how even distinctively rough surfaces can be addressed, which otherwise represent particularly challenging substrates.

Succinimidyl Carbonate-Based Amine-Reactive Polymer Brushes: Facile Fabrication of Functional Interfaces

Polymeric coatings that can undergo effective functionalization with ligands and (bio)molecules necessary for intended applications are widely employed to engineer functional interfaces. Herein, amine-reactive polymer brushes are fabricated using a succinimidyl group-activated carbonate monomer, and their facile post-polymerization functionalization is demonstrated through ligand-mediated protein immobilization and detection. Copolymer brushes containing varying amounts of the reactive monomer and an ethylene glycol-based methacrylate comonomer were obtained using surface-mediated reversible addition fragmentation chain transfer polymerization. Post-polymerization functionalization of the thus-obtained copolymer brushes with a fluorine-containing amine, namely, 4-(trifluoromethyl)benzylamine, demonstrated highly efficient functionalization at ambient temperature. To demonstrate possible applications, polymer brushes functionalized with a bioactive ligand, namely, biotin, were used to detect the target protein, streptavidin. The biotin–streptavidin interaction on brushes could also be employed to conjugate protein-coated quantum dots. Importantly, comparison of the attachment of 4-(trifluoromethyl)benzylamine on activated carbonate group-containing brushes with reaction of the same molecule on traditional active ester-based brushes demonstrated higher extent of conjugation to carbonate brushes. Finally, orthogonal functionalization of the copolymer brushes with an amino-functionalized molecule and a maleimide-containing fluorescent dye in spatial control using microcontact printing was demonstrated. One can envision that the facile fabrication and efficient functionalization of succinimidyl carbonate-based amine-reactive brushes afford an attractive platform for applications using functional interfaces for diagnostic purposes.

High‐Resolution Patterned Functionalization of Slippery “Liquid‐Like” Brush Surfaces via Microdroplet‐Confined Growth of Multifunctional Polydopamine Arrays

AbstractSlippery omniphobic covalently attached liquids enable smooth, transparent, pressure‐ and temperature‐resistant, and liquid‐repellent coatings. Patterned functionalization of such surfaces would drive technology developments and fundamental understandings in broad applications from biosensors to sustainable smart surfaces. Herein an additive microcontact printing approach in combination with the microdroplet‐confined synthesis is developed to functionalize slippery surfaces tethered with “liquid‐like” linear poly(dimethylsiloxane) by multifunctional polydopamine (PDA) arrays. Using glycerol and non‐ionic surfactant Tween‐20, microdroplet arrays containing dopamine monomers are printed onto the slippery surfaces and serve as microreactors for the in situ growth of PDA micropatterns. The confined growth approach enables tunable feature size, height, and morphology of the patterns, through which sub‐micrometer PDA dot arrays over centimeter‐square patterning area can be reliably achieved. Furthermore, the reactive and hydrophilic PDA micropatches allow further functionalization of the slippery surfaces with a diverse variety of materials, meanwhile the anti‐fouling and dynamically dewetting “liquid‐like” brushes permit minimum background contamination. Proof‐of‐concept demonstrations include PDA‐initiated photografting for stimuli‐responsive polymer functionalization, protein immobilization for microarray‐based immunoassays, as well as sliding‐induced selective dewetting of organic solutions to pattern photoluminescent perovskite microcrystals and nanoparticles. The current approach illustrates the potential for applying patterned slippery surfaces with multifunctional architectures in many fields.

Recent Development in Liquid Metal Materials.

Liquid metals (LM) have shown a very broad development prospect over the past decades. This review article focuses on the latest research dedicated to liquid metal materials and their applications in five significant areas: stretchable conductive composite, intelligent sensing electronic skin, catalysis, 3D printing material, and driving machines. The fabrication, specific properties and application of stretchable liquid metal‐polymer composites that can be used as self‐healing materials have been summarized. Liquid metal deposition printing technology, liquid phase 3D printing, suspension 3D printing technology, micro‐contact printing technology, and in vivo 3D printing molding technology have also been reviewed. Furthermore, the application of liquid metal catalyst in aldehyde reaction, photocatalysis, and electrocatalysis have been discussed. We have shown that electricity, magnetism, sound, light and heat could stimulate the movement of liquid metal. Through this comprehensive overview of the latest research, the main practical application, development, and mechanism of liquid metal were summarized and described. The future development of liquid metal technology was prospected, thus providing a strong basic research support for the further development of LM materials and their applications.

One-step harvest and delivery of micropatterned cell sheets mimicking the multi-cellular microenvironment of vascularized tissue

Techniques for harvest and delivery of cell sheets have been improving for decades. However, cell sheets with complicated patterns closely related to natural tissue architecture were hardly achieved. Here, we developed an efficient method to culture and harvest cell sheets with complex shape (noted as microtissues) using temperature-responsive hydrogel consisting of expandable polyethylene oxide polymer at low temperature. Firstly, a temperature-responsive hydrogel surface with honeycomb patterns (50 and 100 µm in width) were developed through microcontact printing of polydopamine (PD). The human dermal fibroblasts (HDFBs) and human umbilical vein endothelial cells (HUVECs) spontaneously formed honeycomb-shaped microtissues on the patterned hydrogel surface. The microtissues on the hydrogel were able to be harvested and directly delivered to the desired target through thermal expansion of the hydrogel at 4 °C with an efficiency close to 80% within 10 min which is faster than conventional method based on poly(N-isopropylacrylamide). The microtissues maintained their original honeycomb network and intact structures. Honeycomb-patterned cell sheets also were fabricated through serial seeding of various cell lines, including HDFBs, HUVECs, and human adipose-derived stem cells, in which cells were attached along the honeycomb pattern. The underlying honeycomb patterns in the cell sheets were successfully maintained for 3 days, even after delivery. In addition, patterned cell sheets were successfully delivered in vivo while maintaining an intact structure for 7 days. Together, our findings demonstrate that micropatterned temperature-responsive hydrogel is an efficient method of one-step culturing and delivery of complex microtissues and should prove useful in various tissue engineering applications. Statement of significanceScaffold-free cell delivery techniques, including cell sheet engineering, have been developed for decades. However, there is limited research regarding culture and delivery of microtissues with complex architecture mimicking natural tissue. Herein, we developed a micro-patterned hydrogel platform for the culture and delivery of honeycomb-shaped microtissues. Honeycomb patterns were chemically engineered on the temperature-responsive hydrogel through microcontact printing of polydopamine to selectively allow for human dermal fibroblast or human umbilical vein endothelial cell adhesion. They spontaneously formed honeycomb-shaped microtissues within 24 hr upon cell seeding and directly delivered to various target area including in vivo via thermal expansion of the hydrogel at 4 °C, suggesting that the micro-patterned hydrogel can be an efficient tool for culture and delivery of complex microtissue.

Systematic optimization of triboelectric nanogenerator performance through surface micropatterning

Abstract Since the first papers on triboelectric nanogenerators (TENG) were published in 2012, the performance and efficiency of these novel devices have continued to improve dramatically. Early on, it was found that adding nanostructures to the surfaces of the active materials improved the efficiency as it increased the surface area and thus the amount of charge transfer. While this method of optimization makes logical sense, there has been little systematic work to show exactly how the increased surface area improves TENG performance. Here we propose a simple geometric model showing how arrays of hemispheres can interlock with each other and increase the amount of surface contact based on the spacing between pattern features. We were able to correlate this with a polyamide and polyvinylidene fluoride (PVDF) model system TENG which were patterned using a method based on hot microcontact printing. By tuning the spacing between the pattern features, the output voltage and current can be improved by several times compared to a planar sample. By deepening our understanding of the surface interactions in TENG we can optimize TENG devices in smarter ways to reduce cost and improve performance.

Measuring Single-Cell Platelet Forces via Microcontact-Printed, Reference-Free Traction Force Microscopy Reveals Relationships between Cell Shape, F-Actin Localization, and Force

Platelets bind, spread, and contract to stop bleeding and reinforce hemostatic plugs. Platelet contraction occurs when interactions between actin and myosin create cytoskeletal tension and force generation. In this study, single-cell platelet forces were measured using a novel microcontact-printed, reference-free traction force microscopy approach. This approach facilitates single-cell force measurement on a contiguous topology that enables unrestricted platelet spreading without necessitating platelet removal to calculate force. Microcontact printing is used to deposit a grid of fluorescent bovine serum albumin onto a flexible polydimethylsiloxane substrate. Platelets from healthy donors were washed and seeded onto von Willebrand Factor-coated substrates. Platelets were fixed, stained, and imaged via confocal microscopy to simultaneously visualize fluorescently labeled platelets and grid displacement (used to calculate single-cell force.) Because microcontact-printing facilitates printing the grid on large, scalable surfaces, platelet forces were able to be measured on >100 single-cells per donor (N = 6 donors). Donor-to-donor platelet force variability was examined, and some donors produce significantly more force per platelet than other donors (p<0.01). Even within each donor, ∼15-fold variability in single platelet forces exists. A well-established area-force relationship (more spread cells produce more force) accounts for some variability in force generation, but for cells spread equally, there is still ∼5-fold differences in force generation. After examining the relationship between cell shape and force, a relationship was observed wherein platelets that are more circular produce more force. Additionally, amongst spread platelets, platelets with more spread F-actin produce more force. This versatile method that facilitates measurement of single-cell forces over large areas without restricting cell spreading or requiring cell removal reveals donor variability, cell shape, and F-actin localization as contributors to the large variability of single-platelet forces.

Black Dots: Microcontact Printed Reference-Free Traction Force Microscopy

Cells generate mechanical force to proliferate, locomote, and perform other cellular functions. Measuring cell forces is vital for understanding their health and behavior, but it has been challenging to find techniques that are compatible with live and fixed samples and do not adversely affect cell function. To overcome these limitations, we use microcontact printing to develop a reference-free traction force technique on PDMS for measuring cell forces in vitro. This technique utilizes a fluorescent micropattern dubbed “black dots” underneath cells to quantify surface deformations and ultimately calculate traction forces.

Advances in Micro/Nanoporous Membranes for Biomedical Engineering.

Porous membrane materials at the micro/nanoscale have exhibited practical and potential value for extensive biological and medical applications associated with filtration and isolation, cell separation and sorting, micro-arrangement, in-vitro tissue reconstruction, high-throughput manipulation and analysis, and real-time sensing. Herein, an overview of technological development of micro/nanoporous membranes (M/N-PMs) is provided. Various membrane types and the progress documented in membrane fabrication techniques, including the electrochemical-etching, laser-based technology, microcontact printing, electron beam lithography, imprinting, capillary force lithography, spin coating, and microfluidic molding are described. Their key features, achievements, and limitations associated with micro/nanoporous membrane (M/N-PM) preparation are discussed. The recently popularized applications of M/N-PMs in biomedical engineering involving the separation of cells and biomolecules, bioparticle operations, biomimicking, micropatterning, bioassay, and biosensing are explored too. Finally, the challenges that need to be overcome for M/N-PM fabrication and future applications are highlighted.

SiO2‐Decorated Parylene C Micropillars Designed to Probe Cellular Force

AbstractLiving cells sense and respond to mechanical signals through specific mechanisms generating traction force. The quantification of cell forces using micropillars can be limited by micropillar stiffness, technological aspects of fabrications, and microcontact printing of proteins. This paper develops the new design of SiO2/Parylene C micropillars with an aspect ratio of 6 and 3.5 and spring constant of 4.7 and 28 µN µm−1, respectively. The upper part of micropillars is coated with a 250 nm layer of SiO2, and results confirm protein deposition on individual micropillars via SiO2 interface and non‐adhesiveness on the micropillars’ sidewalls. Results show an absence of cytotoxicity for micropillar‐based substrates and a dependence on its stiffness. Stiffer micropillars enhance cell adhesion and proliferation rate, and a stronger cellular force of ≈25 μN is obtained. The main contribution of SiO2/parylene C micropillars is the elimination of the step involving the fabrication of polydimethylsiloxane stamp because the array enables covalent binding of proteins via SiO2 chemistry. These micropillars stand on Si wafer and thus, any warping of underlying polymer membrane does not have to be considered. Additionally, SiO2/parylene C micropillars can broaden the range of stiffer substrates to be probed by cells.

Fabrication of Silver Mesh/Grid and Its Applications in Electronics.

With the development of flexible electronics, researchers have endeavored to improve the characteristics of the commonly used indium tin oxide such as brittleness, poor mechanical or chemical stability, and scarcity. Currently, many alternative materials have been considered such as conductive polymers, graphene, carbon nanotubes, metallic nanoparticles (NPs), nanowires (NWs), or nanofibers. Among them, silver (Ag) mesh/grid NPs or NWs have been considered as an excellent substitute due to the good transmittance, excellent electrical conductivity, outstanding mechanical robustness, and cost competitiveness. So far, much effort has been devoted to the fabrication of Ag mesh/grid, and many methods such as printing technology, self-assembly, electrospun, hot-pressing, and atomic layer deposition have been reported. Here printing technologies include jet printing, gravure printing, screen printing, nanoimprint lithography, microcontact printing, and flexographic printing. The solution-based self-assembly usually combines with coating, template, or mask assistance. This review summarizes the characteristics of these fabrication methods for the Ag mesh/grid with its related applications in electronics. Then the prospect and challenges of the fabrication methods are discussed, and the new preparation approaches and applications of the Ag mesh/grid are highlighted, which will be of significance for the applications in electronics such as transparent conducting electrodes, organic light-emitting diode, energy harvester, strain sensor, cells, etc.

Multifunctional Printable Micropattern Array for Digital Nucleic Acid Assay for Microbial Pathogen Detection

The digital nucleic acid assay is a precise, sensitive, and reproducible method for determining the presence of individual target molecules separated in designated partitions; thus, this technique can be used for the nucleic acid detection. Here, we propose a multifunctional micropattern array capable of isolating individual target molecules into partitions and simultaneous on-site cell lysis to achieve a direct DNA extraction and digitized quantification thereof. The multifunctional micropattern array is fabricated by the deposition of a copolymer film, poly(2-dimethylaminomethyl styrene-co-hydroxyethyl methacrylate) (pDH), directly on a microfluidic chip surface via the photoinitiated chemical vapor deposition process, followed by hydrophobic microcontact printing (μCP) to define each partition for the nucleic acid isolation. The pDH layer is a positively charged surface, which is desirable for the bacterial lysis and DNA capture, while showing exceptional water stability for more than 24 h. The hydrophobic μCP-treated pDH surface is stable under aqueous conditions at a high temperature (70 °C) for 1 h and enables the rapid and reliable formation of thousands of sessile microdroplets for the compartmentalization of an aqueous sample solution without involving bulky and costly microfluidic devices. By assembling the multifunctional micropattern array into the microfluidic chip, the isothermal amplification in each partition can detect DNA templates over a concentration range of 0.01-2 ng/μL. The untreated bacterial cells can also be directly compartmentalized via the microdroplet formation, followed by the on-site cell lysis and DNA capture on the compartmentalized pDH surface. For Escherichia coli O157:H7, Salmonella enteritidis, and Staphylococcus aureus cells, cell numbers ranging from 1.4 × 104 to 1.4 × 107 can be distinguished by using the multifunctional micropattern array, regardless of the cell type. The multifunctional micropattern array developed in this study provides a novel multifunctional compartmentalization method for rapid, simple, and accurate digital nucleic acid assays.

BIO bragg gratings on microfibers for label-free biosensing

Discovering nanoscale phenomena to sense biorecognition events introduces new perspectives to exploit nanoscience and nanotechnology for bioanalytical purposes. Here we present Bio Bragg Gratings (BBGs), a novel biosensing approach that consists of diffractive structures of protein bioreceptors patterned on the surface of optical waveguides, and tailored to transduce the magnitude of biorecognition assays into the intensity of single peaks in the reflection spectrum. This work addresses the design, fabrication, and optimization of this system by both theoretical and experimental studies to explore the fundamental physicochemical parameters involved. Functional biomolecular gratings are fabricated by microcontact printing on the surface of tapered optical microfibers, and their structural features were characterized. The transduction principle is experimentally demonstrated, and its quantitative bioanalytical prospects are assessed in a representative immunoassay, based on patterned protein probes and selective IgG targets, in label-free conditions. This biosensing system involves appealing perspectives to avoid unwanted signal contributions from non-specific binding, herein investigated in human serum samples. The work also proves how the optical response of the system can be easily tuned, and it provides insights into the relevance of this feature to conceive multiplexed BBG systems capable to perform multiple label-free biorecognition assays in a single device.

Discrete fluid lipid membrane compositional array created with chrome and protein barriers

To understand various interactions with cell membranes for in-vivo studies array of different lipid compositions becomes important. Work presented here shows how to prepare different lipid compositions for two different lipids with the help of micro-contact printing and photolithography. Firstly, barriers were created on hydrophilic surface by chrome patterning and/or by protein patterning. Secondly, lipid membrane of desired fluid lipid composition containing one or more lipids in it can be printed by micro-contact printing on to the surface containing chrome or protein patterns. It results in formation of 5 nm thick lipid membrane pattern partitioned with protein or chrome patterns. Thirdly, secondary intercalation can be done by adding small unilamellar vesicles of fluid lipid composition containing one or more lipids to the earlier patterned surface. Upon backfilling with the secondary vesicles it results in formation of compositional array lipid membrane patterns upon mixing with the existing patterned bilayer due to lateral fluidity.

Microfluidic assay of antiplatelet agents for inhibition of shear-induced platelet adhesion and activation.

We have developed a microfluidic system to perfuse whole blood through a flow channel with an upstream stenotic region and a downstream protein capture region. This flow-based system was used to assay how effectively antiplatelet agents suppress shear-induced platelet adhesion and activation downstream of the stenotic region. Microcontact printing was used to covalently attach one of three platelet binding proteins [fibrinogen, collagen, or von Willebrand factor (vWf)] to the surface of the downstream capture region. Whole blood with an antiplatelet agent was transiently exposed to an upstream high wall shear rate (either 4860 s-1 or 11 560 s-1), and subsequently flowed over the downstream capture region where the platelet adhesion was measured. Several antiplatelet agents (acetylsalicylic acid, tirofiban, eptifibatide, anti-vWf, and anti-GPIbα) were evaluated for their efficacy in attenuating downstream adhesion. Following antibody blocking of vWf or GPIbα, downstream platelet activation was also assessed in perfused blood by flow cytometry using two activation markers (active GPIIb/IIIa and P-selectin). Acetylsalicylic acid demonstrated its inability to diminish shear-induced platelet adhesion to all three binding proteins. GPIIb/IIIa inhibitors (tirofiban and eptifibatide) significantly reduced platelet adhesion to fibrinogen. Antibody blocking of vWf or GPIbα effectively diminished platelet adhesion to all three capture proteins as well as platelet activation in perfused blood, indicating an essential role of vWf-GPIbα interaction in mediating shear-induced platelet aggregation.

Micropatterned Smart Culture Surfaces via Multi-Step Physical Coating of Functional Block Copolymers for Harvesting Cell Sheets with Controlled Sizes and Shapes.

Cell micropatterning on micropatterned thermoresponsive polymer-based culture surfaces facilitates the creation of on-demand and functional cell sheets. However, the fabrication of micropatterned surfaces generally includes complicated procedures with multi-step chemical reactions. To overcome this issue, this study proposes a facile preparation of micropatterned thermoresponsive surfaces via a two-step physical coating of two different diblock copolymers. Both copolymers contain poly(butyl methacrylate) blocks as hydrophobic anchors for water-stable polymer deposition. At first, thermoresponsive polymer layers are constructed on cell culture dishes via spin-coating block copolymers containing poly(N-isopropylacrylamide) blocks that exhibit a transition temperature of ≈30°C in aqueous media. To create polymer micropatterns on the thermoresponsive surfaces, microcontact printing of block copolymers containing hydrophilic poly(N-acryloylmorpholine) (PNAM) blocks is performed using polydimethylsiloxane stamps. Stamped PNAM-based block polymers are adsorbed to the outermost thermoresponsive surfaces, and increase the surface hydrophilicity with decreasing protein adsorption. Cells adhere and proliferate on the thermoresponsive domains at 37°C, whereas the stamped hydrophilic domains remain cell-repellent for 7 days. At 20°C, cell sheets with controlled sizes and shapes are harvested from the surfaces with the desired micropatterns. This technique is useful for the preparation of micropatterned polymer surfaces for various biomedical applications.

Capillary Stamping of Functional Materials: Parallel Additive Substrate Patterning without Ink Depletion

AbstractPatterned substrates for optics, electronics, sensing, lab‐on‐chip technologies, bioanalytics, clinical diagnostics as well as translational and personalized medicine are typically prepared by additive substrate manufacturing including ballistic printing and microcontact printing. However, ballistic printing (e.g., ink jet and aerosol jet printing, laser‐induced forward transfer) involves serial pixel‐by‐pixel ink deposition. Parallel additive patterning by microcontact printing is performed with solid elastomeric stamps suffering from ink depletion after a few stamp‐substrate contacts. The throughput limitations of additive state‐of‐the art patterning thus arising may be overcome by capillary stamping –parallel additive substrate patterning without ink depletion by mesoporous silica stamps, which enable ink supply through the mesopores anytime during stamping. Thus, either arrays of substrate‐bound nanoparticles or colloidal nanodispersions of detached nanoparticles are accessible. Three types of model inks are processed: 1) drug solutions, 2) solutions containing metallopolymers and block copolymers as well as 3) nanodiamond suspensions representing colloidal nanoparticle inks. Thus, aqueous colloidal nanodispersions of stamped drug nanoparticles, regularly arranged ceramic nanoparticles by post‐stamping pyrolysis of stamped metallopolymeric precursor nanoparticles and regularly arranged nanodiamond nanoaggregates are obtained. Capillary stamping may overcome the throughput limitations of state‐of‐the‐art additive substrate manufacturing while a broad range of different inks can be processed.

Microstructuring GaAs Using Reverse-Patterning Lithography: Implications for Transistors and Solar Cells

This paper introduces reverse patterning lithography (RPL), which combines microcontact printing (μCP) of a custom-designed fluorinated adsorbate on gallium arsenide (GaAs) and the deposition of a ...