|Jun 06, 2019|
3D microchannels promote self-assembly of ordered emulsions at low droplet concentrations(Nanowerk News) Self-assembly is the process by which simple building blocks interact and organize themselves into ordered structures. Nature abounds with fascinating examples of self-assembled structures. Inspired by nature, researchers have long sought to exploit self-assembly as a "bottom-up" fabrication technique to engineer complex materials and devices.
|Currently, the self-assembly of ordered emulsions has elicited much interest for its potential application in multiple fields such as material synthesis and high throughput analysis.|
|Microfluidic techniques offer the ability to generate and self-assemble highly monodisperse droplets into ordered emulsions in a single device, but self-assembly in microfluidic flows typically requires high droplet density.|
|A team of researchers led by Assistant Professor Michinao Hashimoto from the Singapore University of Technology and Design (SUTD) has discovered an elegant way to achieve self-assembly of low density droplets in microfluidic flows using three dimensional (3D) microchannels (Soft Matter, "Self-assembly of droplets in three-dimensional microchannels").|
|One, two and three layers of self-assembled droplets in 3D microchannels. (Image: SUTD)|
|In contrast to previous studies which used microchannels with no variations in height, the researchers at SUTD used a microchannel with a gradual increase in height. In such 3D microchannels, the droplets, unconfined by the top or bottom walls and driven by a density difference with the surrounding liquid, either sink to the bottom of the microchannel or float to the top of microchannel. They then accumulate, jam and self-assemble into ordered structures.|
|The research team demonstrated that self-assembly into 2D lattices could be achieved when droplets occupied just 5% of the total volume of liquid injected into the microchannel; and by gradually increasing the droplet concentration beyond that, self-assembly into 3D lattices could be achieved.|
|To further demonstrate the potential of their discovery the researchers used self-assembled 2D lattices of droplets as a template to fabricate millimeter wide hydrogel fibers with anisotropic pore structures.|
|"The simplicity and versatility of the concept--the use of 3D microfluidics for the controlled self-assembly of droplets--should be of interest to researchers exploring the interface between microfluidics, self-assembly, and soft matter" said Dr. Pravien Parthiban, a postdoctoral fellow at SUTD and the lead author involved in the work.|
|Source: Singapore University of Technology and Design|
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