Micro‐Patterning Wettability in Very Large Scale Microfluidic Integrated Chips for Double Emulsion Generation

Abstract

The fabrication of microfluidic chips is becoming a mature field and channels can be reliably defined with micrometer‐scale precision in a variety of substrates. In addition to channel geometry, micrometer‐scale patterning of wettability in microfluidic channels is essential for many applications including multi‐phase flow stabilization and multiple emulsion generation. Unfortunately, current methods to pattern wettability in microfluidics suffer from low spatial resolution, inability for patterns to be arbitrarily defined, cumbersome procedures, and incompatibility with parallelized architectures for scaled‐up production of microfluidic generated materials. To address these issues, a method is developed to lithographically define micrometer‐scale resolution patterns of wettability on all channel surfaces (ceiling, floor, and walls) in silicon and glass microfluidic devices with complex 3D geometry. A process is reported to pattern silanes on microfluidic chips that uses photolithography and an optimized process that keeps silanized surfaces stable through the microfabrication process, including anodic bonding. The versatility of this approach is highlighted by patterning wettability of a silicon/glass device to generate both highly uniform water–in‐oil–in‐water and oil–in‐water–in‐oil double emulsions. The applicability of this process is demonstrated to the parallel generation of materials in a microfluidic chip with complex geometry, by fabricating and successfully validating parallelized double emulsion generators.

Microarray Platforms Based on 3D Printing

“…Wettabilitypatterned microchips, while simple to fabricate and capable of quickly generating uniform arrays, suffer from relatively poor operability and volumetric accuracy. 13,14 Microfluidic dispensing methods based on microchannels represent a natural and relatively precise approach. These often leverage the gas permeability of PDMS assisted by vacuum to fill dead-end microchambers, allowing for the loading of different types of reagents.…”

“…Methods based on robotics and electronic devices, such as focused acoustics, piezoelectric or air pressure-driven inkjet systems, , electrowetting, and automatic liquid handling ,, require intricate electronic and mechanical control systems, leading to high manufacturing and operational costs, as well as technical complexity. Wettability-patterned microchips, while simple to fabricate and capable of quickly generating uniform arrays, suffer from relatively poor operability and volumetric accuracy. , Microfluidic dispensing methods based on microchannels represent a natural and relatively precise approach. These often leverage the gas permeability of PDMS assisted by vacuum to fill dead-end microchambers, allowing for the loading of different types of reagents. , Nevertheless, conventional soft lithography techniques have certain barriers to entry such as the need for photolithographic equipment, various photoresists, clean room environments, and operational skills.…”

Effects of Rheological Properties of Non-Newtonian Middle Fluids on the Formation Dynamics of Double Emulsions in Coflowing Microfluidic Emulsification

“…In the past decade, various geometric configurations of microfluidic devices including T-junction, , flow-focusing, − and coflowing − have been employed to generate double emulsions. In these configurations, since the dispersed phase is completely surrounded by another immiscible continuous phase in the coflowing microfluidic device, the wettability of channel wall exhibits an ignorable effect on the generation of double emulsions.…”

Dual-Ligand Red Perovskite Ink for Electrohydrodynamic Printing Color Conversion Arrays over 2540 dpi in Near-Eye Micro-LED Display

“…The deposited red, green, and blue PeNCs can be effectively excited by the ultraviolet micro-LED chips and emit three primary colors and can act as the subpixels . At present, the patterning methods of all-inorganic PeNCs include template method, , inkjet printing, photolithography, laser direct writing, microfluidics, and transfer printing . Among them, electrohydrodynamic (EHD) inkjet printing technology possesses the advantages of masklessness, digital operation, high material utilization ratio, and ultrahigh patterning resolution. , …”