On-Chip Liquid Manipulation via a Flexible Dual-Layered Channel Possessing Hydrophilic/Hydrophobic Dichotomy

Abstract

The hydrophilic/hydrophobic cooperative interface provides a smart platform to control liquid distribution and delivery. Through the fusion of flexibility and complex structure, we present a manipulable, open, and dual-layered liquid channel (MODLC) for on-demand mechanical control of fluid delivery. Driven by anisotropic Laplace pressure, the mechano-controllable asymmetric channel of MODLC can propel the directional slipping of liquid located between the paired tracks. Upon a single press, the longest transport distance can reach 10 cm with an average speed of ∼3 cm/s. The liquid on the MODLC can be immediately manipulated by pressing or dragging processes, and versatile liquid-manipulating processes on hierarchical MODLC chips have been achieved, including remote droplet magneto-control, continuous liquid distributor, and gas-producing chip. The flexible hydrophilic/hydrophobic interface and its assembly can extend the function and applications of the wettability-patterned interface, which should update our understanding of complex systems for sophisticated liquid transport.

Spontaneous Separation of Immiscible Organic Droplets on Asymmetric Wedge Channels with Hierarchical Microchannels

“…As shown in Figure a, a mixed organic droplet of 5 μL was deposited on top of the parallel channel. The mixed organic drops in the parallel channel were completely separated within 68 s. Researchers found that water droplets can be transported rapidly and directedly from the nonparallel channel’s open side (the root of SHMW) to the corner (top of SHMW). , As shown in Figure b, the mixed organic droplet was deposited on the open side of the nonparallel channel and transported both octane and glycol to the top of the nonparallel channel. Although the nonparallel channel can achieve ultrafast transport of liquid droplets, mixed organic droplets cannot be separated by the nonparallel channel.…”

“…The asymmetrically tapered structure of the cactus enables the rapid transportation and collection of water droplets for its growth. Inspired by these biologically self-transporting droplet methods, the study of open surface-based spontaneous fluid transport has been widely reported, providing new ideas for microfluidics, liquid collection, and separation processes. − Spontaneous fluid transport based on open surfaces can be realized for oil–water separation, emulsion separation, and other related processes. − Based on the repeated opening and closing action of the beak when shorebirds drink water, Lou et al. achieved a microscale oil–water mixture separation by squeezing the mixture using two nonparallel plates .…”

Bionic Surfaces for Fog Collection: A Comprehensive Review of Natural Organisms and Bioinspired Strategies

“…Driven by the anisotropic Laplace pressure, droplets can move directionally in the MODLC. The maximum transmission distance can reach 10 cm and the average speed is about 3 cm/s when a single compression is performed . Such a directional transport structure is conducive to fog collection. , Drawing inspiration from the predation behavior of shorebirds, a branch-structure elastic three-dimensional space fabric with a structure similar to that of the beak of shorebirds is developed (Figure b).…”

Fabrication of Janus Composite Membranes with a Gradient Pore Structure Based on Melt Electrowriting and Solution Electrospinning for Directional Water Transport

“…Current research focuses on the development of bilayer membranes thanks to their high potential for moisture transportation by individually altering the composition and structure of each layer. 7,8 The bilayer membranes, also known as Janus membranes, are usually composed of a hydrophobic inner layer and a hydrophilic outer layer. 9 The asymmetric wettability in the thickness direction can achieve the effect of one-way directional water transportation.…”

“…This functionalized textile drives sweat from the skin while it can restrain the opposite permeation. Current research focuses on the development of bilayer membranes thanks to their high potential for moisture transportation by individually altering the composition and structure of each layer. , The bilayer membranes, also known as Janus membranes, are usually composed of a hydrophobic inner layer and a hydrophilic outer layer . The asymmetric wettability in the thickness direction can achieve the effect of one-way directional water transportation. − The hydrophilic layer in the Janus membrane mainly relies on a driving force to guide water transport, and the small pore size is conducive to rapid water transport (capillary transport).…”