uVALVIT: A tool for droplet mobility control and valving

Abstract

Abstract. Active control of droplet mobility through low cost tools is highly desirable in applications entailing microfluidics, Lab-on-Chip devices and pertinent technologies. Here, we present the design concepts of a versatile, low cost tool for dynamic droplet mobility manipulation, employing a scheme with backpressure application. Initially sticky open-or closed-channel fluidics with hydrophobic, porous walls are rendered slippery with the application of backpressure through the porous walls. Deliberate control of backpressure directs the wetting phenomena to the desired state. Operation parameters, and control system considerations are presented. Ultra-low backpressure values, are needed for channels with small cross-sections, which in turn are compatible with ultra-low energy demands.

A new microfluidic pressure-controlled Field Effect Transistor (pFET) in digital fluidic switch operation mode

“…The honeycombs were cut and machined to the required dimensions and geometry, leaving a central channel open on the top face. This channel after dry surface modification, to render the porous surfaces hydrophobic, serves as the fluidic channel [37][38][39][40][41]. Similarly, porous and hydrophobic structures prepared by alternative routes, such as 3d-printing may also be used.…”

Droplet Mobility Manipulation on Porous Media Using Backpressure

“…In this direction, we have recently developed a method for droplet actuation and mobility manipulation on porous media, − which has found application in open-channel fluidic valving , and in mobility control after impingement . Contrary to the droplets levitated by an air cushion exhibiting frictionless mobility, our method provokes only partial depinning of the solid–liquid interface, which is enough to render the droplet mobile and to incite downward movement.…”