Colloidal Pixel‐Based Micropatterning Using Uniform Janus Microparticles with Tunable Anisotropic Particle Geometry

Abstract

A new platform for designing 2D colloidal arrays by using Janus microparticles (JMPs) with tunable anisotropic particle geometry is introduced. The JMPs are synthesized by the photopolymerization of biphasic emulsion droplets produced by capillary‐based microfluidics while adjusting the spreading coefficient between −4.4 and −7.2 mN m−1. The unidirectional rubbing of JMPs leads to their exact positioning in the stencil holes. The ratio of the hole diameter to the bigger bulb diameter of JMPs, ranging from 1.05–1.16, is critical for maximizing the positioning rate. When the anisotropic geometry factor is near zero, a standing particle configuration with a protrusion in the stencil hole is obtained more efficiently due mainly to the enhanced steric constraint. Finally, it is demonstrated that different types of JMPs with controlled sizes and geometries can be arrayed at specific hole sites of the stencil, thus enabling development of a colloidal pixel‐based micropatterning technology.

Janus Nanoparticles: From Fabrication to (Bio)Applications

“…prepared multifunctional particles by electrohydrodynamic cojetting of poly­(lactide- co -glycolide) (PLGA) polymer solutions to present a gathering of disks, rods, and spheres, as illustrated in Figure D . The convenient method allowed for the development of enlarging the geometry analysis of JNPs. , There is still an unmet need for a microfluidic preparation strategy to improve the size distribution. The JNPs produced by this strategy were in the micro- or millimeter scale and, therefore, were a challenge to be directly applied for biomedical applications.…”

Anisotropic Microparticles from Microfluidics

“…They employed external factors to drive the phase separation, but when droplets involved two or more immiscible phases, they actively underwent phase separation due to the difference in the spreading coefficient. [114][115][116][117][118][119] For instance, Kim and coworkers proposed Janus microparticles with tunable anisotropic geometry and investigated the relevance between the morphology of resultant particles and spreading coefficient. 115 As they demonstrated, in a certain range of spreading coefficient, the dewetting of droplets containing two immiscible fluids occurred upon the production at the tip end of the capillary and the morphology of the droplets reached equilibrium after traveling certain distance.…”

“…[114][115][116][117][118][119] For instance, Kim and coworkers proposed Janus microparticles with tunable anisotropic geometry and investigated the relevance between the morphology of resultant particles and spreading coefficient. 115 As they demonstrated, in a certain range of spreading coefficient, the dewetting of droplets containing two immiscible fluids occurred upon the production at the tip end of the capillary and the morphology of the droplets reached equilibrium after traveling certain distance. By adjusting flow rates, particles with controllable anisotropy could be obtained with polymerization of UV light.…”

Microfluidic production of monodisperse emulsions for cosmetics

“…Emulsions have been applied in numerous ways from traditional food, pharmaceutical, and cosmetic industries to technology-oriented biomedical and sensor industries. [1][2][3][4][5][6][7] Therefore, it is important to understand recent research trends regarding the development of a diverse emulsion system. To date, conventional emulsification methods commonly used in industries such as paddle mixing, simple homogenization, and high-pressure homogenization have been focusing only on the technical aspect of simply mixing two immiscible oil and water phases with the aid of a surfactant.…”