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

Colloidal crystals have brought the promise of revolution to modern engineering, 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 self-assembly 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 monolayers 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 close-packed nanoparticle monolayers into large-area conformal micropatterns 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.

Automated summary

A surface tension gradient-driven self-assembly strategy is proposed for the ultrafast fabrication of large-area colloidal crystals, and an ultrafast nanoparticle transfer printing method is proposed for the conversion of close-packed nanoparticle monolayers into large-area conformal micropatterns. These methods show great potential for academic and real industrial applications.