Continuous microwire patterns dominated by controllable rupture of liquid films

A general strategy for printing colloidal nanomaterials into one-dimensional micro/nanolines

Though patterned one-dimensional (1D) micro/nanoline arrays are of great importance in the field of integrated circuits and optoelectronics, the fabrication of high-precision micro/nanolines with excellent optical and electrical performance remains a great challenge. Herein, a general strategy for printing 1D micro/nanolines is proposed by manipulating the self-assembly of functional nanoparticles as a multilayer or monolayer stack with a single-nanoparticle width. This method is universal for dispersible nanoparticles, and the silver nanoparticle was selected as a model nanoparticle due to its good conductivity, dispersibility and narrow-size distribution. The results indicate that the morphologies of printed micro/nanolines can be precisely regulated by the substrate wettability and the suspension concentration. Specifically, 1D nanoparticle-assembled architectures are printed as a monolayer stack on the substrate with a low contact angle (below 45°), while a multilayer stack is formed on the substrate with a high contact angle (above 50°) or a high concentration (more than 0.12%). The controllability of micro/nanoline morphologies can be interpreted through the influence of the three phase contact line slipping motion and the nanoparticle diffusion on diverse substrates at different concentrations. Alteration of the printing template structures enables the intervals of 1D micro/nanolines to span from 16 μm to 48 μm. These results provide an efficient methodology for fabricating micro/nano-circuits or optics and strengthening the understanding of the self-assembling process.

Printable Functional Chips Based on Nanoparticle Assembly

With facile manufacturability and modifiability, impressive nanoparticles (NPs) assembly applications were performed for functional patterned devices, which have attracted booming research attention due to their increasing applications in high-performance optical/electrical devices for sensing, electronics, displays, and catalysis. By virtue of easy and direct fabrication to desired patterns, high throughput, and low cost, NPs assembly printing is one of the most promising candidates for the manufacturing of functional micro-chips. In this review, an overview of the fabrications and applications of NPs patterned assembly by printing methods, including inkjet printing, lithography, imprinting, and extended printing techniques is presented. The assembly processes and mechanisms on various substrates with distinct wettabilities are deeply discussed and summarized. Via manipulating the droplet three phase contact line (TCL) pinning or slipping, the NPs contracted in ink are controllably assembled following the TCL, and generate novel functional chips and correlative integrate devices. Finally, the perspective of future developments and challenges is presented and widely exhibited.

Capillary Force Driven Self-Assembly of Anisotropic Hierarchical Structures Prepared by Femtosecond Laser 3D Printing and Their Applications in Crystallizing Microparticles

The hierarchical structures are the derivation of various functionalities in the natural world and have inspired broad practical applications in chemical systhesis and biological manipulation. However, traditional top-down fabrication approaches suffered from low complexity. We propose a laser printing capillary-assisted self-assembly (LPCS) strategy for fabricating regular periodic structures. Microscale pillars are first produced by the localized femtosecond laser polymerization and are subsequently self-assembled into periodic hierarchical architectures with the assistance of controlled capillary force. Moreover, based on anisotropic assemblies of micropillars, the LPCS method is further developed for the preparation of more complicated and advanced functional microstructures. Pillars cross section, height, and spatial arrangement can be tuned to guide capillary force, and diverse assemblies with different configurations are thus achieved. Finally, we developed a strategy for growing micro/nanoparticles in designed spatial locations through solution-evaporation self-assembly induced by morphology. Due to the high flexibility of LPCS method, the special arrangements, sizes, and distribution density of the micro/nanoparticles can be controlled readily. Our method will be employed not only to fabricate anisotropic hierarchical structures but also to design and manufacture organic/inorganic microparticles.

Instability, self-organization and pattern formation in thin soft films

The free surface of a thin soft polymer film is often found to become unstable and self-organizes into various meso-scale structures. In this article we classify the instability of a thin polymer film into three broad categories, which are: category 1: instability of an ultra-thin (<100 nm) viscous film engendered by amplification of thermally excited surface capillary waves due to interfacial dispersive van der Waals forces; category 2: instability arising from the attractive inter-surface interactions between the free surface of a soft film exhibiting room temperature elasticity and another rigid surface in its contact proximity; and category 3: instability caused by an externally applied field such as an electric field or a thermal gradient, observed in both viscous and elastic films. We review the salient features of each instability class and highlight how characteristic length scales, feature morphologies, evolution pathways, etc. depend on initial properties such as film thickness, visco-elasticity (rheology), residual stress, and film preparation conditions. We emphasize various possible strategies for aligning and ordering of the otherwise isotropic structures by combining the essential concepts of bottom-up and top-down approaches. A perspective, including a possible future direction of research, novelty and limitations of the methods, particularly in comparison to the existing patterning techniques, is also presented for each setting.

Fabrication of Nanoscale Circuits on Inkjet-Printing Patterned Substrates

Nanoscale circuits are fabricated by assembling different conducting materials (e.g., metal nanoparticles, metal nano-wires, graphene, carbon nanotubes, and conducting polymers) on inkjet-printing patterned substrates. This non-litho-graphy strategy opens a new avenue for integrating conducting building blocks into nanoscale devices in a cost-efficient manner.

A general strategy for assembling nanoparticles in one dimension

Alignment of 1D assemblies of a wide variety of nanoparticles (e.g., metal, metal oxide, semiconductor quantum dots, or organic microspheres) in one direction upon diverse substrates (including industrial silicon wafers and transparent glass plates) by a general strategy is demonstrated. This sandwich method provides an efficient way of rapidly and precisely assembling nanoparticles on a large scale (up to 10 cm × 10 cm) for device applications.