Fabrication of a Micro-omnifluidic Device by Omniphilic/Omniphobic Patterning on Nanostructured Surfaces

We integrate the adhesive properties of marine mussels, the lubricating properties of pitcher plants, and the nonfouling properties of diatoms into nanostructured surfaces to develop a device called a micro-omnifluidic (μ-OF) system to solve the existing challenges in microfluidic systems. Unlike conventional poly(dimethylsiloxane)-based fluidic systems that are incompatible with most organic solvents, the μ-OF system utilizes a variety of solvents such as water, ethanol, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, <i>n</i>-hexane, 1,2-dichloroethane, acetic acid, 2-propanol, acetone, toluene, diesel oil, dioxane, gasoline oil, hexadecane, and xylene. The μ-OF system is based on a phenomenon called microchannel induction that spontaneously occurs when virtually all droplets of solvents are applied on omniphilically micropatterned regions of a slippery liquid-infused porous surface. Any solvents with surface tension greater than that of the lubricant (17.1 mN/m, Fluorinert FC-70) are able to repel the infused lubricant located on top of the omniphilic microlines, triggering controlled movement of the droplet by gravity along the microlines. We also demonstrated that the μ-OF system is reusable by the nonadsorption properties of the silicified layer. Due to the organic solvent compatibility, we were able to perform organic reactions with high portability and energy efficiency in operation

Leaf Vein-Inspired Electrospraying System by Grafting Origami

Stable, long-term divisions of a water stream into two or more under electric fields (often for electrospray) have not been achieved owing to water’s high surface tension (72 dyn/cm), even though it seems to be a simple technical problem. In nature, leaf veins evenly distribute water to cells, despite the numerous bifurcating divisions of veins. The main reason is the extensive interconnections among veins. Herein, we discuss a stably operating multichannel water electrospray system. The system is called a “<u>L</u>eaf vein-inspired <u>E</u>lectrospraying system by <u>G</u>rafting <u>O</u>rigami (LEsGO)” and was inspired by leaf vein structures. LEsGO is a hierarchical electrospraying system prepared with cellulose paper; multiple channels can be constructed through the simple grafting of a two-channel paper unit. We demonstrate a 600% increase in water-spraying performance in an eight-channel LEsGO compared with conventional single-nozzle systems. LEsGO may potentially contribute to devices such as mass analyzers, microencapsulators, and dust removers