Ultrafast Fabrication of Large‐Area Colloidal Crystal Micropatterns via Self‐Assembly and Transfer Printing

Abstract

Colloidal crystals have brought the promise of revolution to modernengineering, yet commonly used fabrication technologies are still limited by the small preparation area, time-consuming process, and dependence on sophisticated equipment. Here, a surface tension gradient-driven selfassembly strategy is proposed for the ultrafast fabrication of large-area colloidal crystals. The hydrogel loaded with sodium dodecyl sulfate is devised to construct a stable and continuous liquid-air interfacial tension gradient, and the resulting Marangoni effect can drive the micro-nano particles to instantaneously form (within several seconds) highly ordered colloidal crystals. Benefiting from the long range of surface tension gradients, the fabrication area of colloidal crystal films is demonstrated to exceed an astonishing 1000 cm 2 without compromising their quality, showing great potential in scale-up manufacture. Moreover, particles of a wide variety of sizes, materials, and functionalities can form close-packed self-assembly mono layers and be transferred to various substrates without damage, exhibiting great versatility. Inspired by ink microprinting, an ultrafast nanoparticle transfer printing method is further proposed to convert the closepacked nanoparticle mono layers into large-area conformal micro patterns with single-nanoparticle resolution. The great potential of nanoparticle micropatterns is demonstrated in flexible micro-electronics/skin electronics. This user-friendly, efficient self-assembly, and micropatterning strategy provide promising opportunities for academic and real industrial applications.

High-Throughput and Efficient Intracellular Delivery Method via a Vibration-Assisted Nanoneedle/Microfluidic Composite System

“…In general, the preparation of nanostructures depends on nanolithography, which has significant problems such as small preparation area, slow preparation speed, and high cost. − To overcome such limitations, we propose a self-assembly template method based on the large-area self-assembly technique to replace photolithography, so that large areas of high-quality nanoneedle arrays can be prepared quickly at a low cost. In previous work, we have proposed a variety of self-assembly methods of large-area (∼1000 cm 2 ) colloidal crystal films, − which allowed for the preparation area of nanoneedle structures in this work to be adjusted within hundreds of square centimeters. The schematic image of this strategy is illustrated in Figure a.…”

“…The large-area nanoparticle monolayer was fabricated by the tension gradient-driven rapid nanoparticle self-assembly method. , After sonication to complete dispersion, the hydrophobic polystyrene nanoparticle colloidal solution was dropped to the liquid surface to form a loosely compacted particle monolayer. Then, the hydrogel loaded with surfactant was immersed into the liquid to induce a liquid–air interfacial tension gradient to drive the particles to compress quickly to form a closely packed monolayer.…”

Bio-inspired water-driven electricity generators: From fundamental mechanisms to practical applications

“…Since the microstructures of organisms such as lotus leaf and water strider were discovered [73,74], bio-inspired textured surfaces have been rapidly developed. Various methods have been developed to modulate surface wettability, which greatly promote the development of water-driven electricity generators [20,35,[74][75][76][77][78][79][80][81][82][83][84]. Therefore, an understanding of the effect of texture on the hydrophobicity of materials is necessary.…”

Design and Self-Assembly of Polyhedron Particles to Construct Iridescent Structural Colors

“…Anisotropic nonspherical particles have attracted considerable interest due to their promising applications in structural colors, − sensors, , biometrics, , and smart displays. , One of the key interests is anisotropic polyhedron particles. Compared with highly symmetrical spheres, nonspherical polyhedron particles process unique physical properties such as different curvature, charge distribution, and so on, which are usually used as basic building blocks to construct novel materials.…”

“…In addition, the alternating iridescent colors from inside to outside are diffraction rings caused by different diffraction orders (Figure e). While the spherical particle arrays only display the same colors , (only “A” in Figure g). Given the particle arrays showing bright structural color, the letters “DUT” (abbreviation of Dalian University of Technology), traffic sign patterns, and numbers (see Figure S3) were prepared by laser etching.…”