Some recent advances in the design and the use of miniaturized droplet-based continuous process: Applications in chemistry and high-pressure microflows

Abstract

This mini-review focuses on two different miniaturizing approaches: the first one describes the generation and use of droplets flowing within a millifluidic tool as individual batch microreactors. The second one reports the use of high pressure microflows in chemistry. Millifluidics is an inexpensive, versatile and easy to use approach which is upscaled from microfluidics. It enables one to produce hierarchically organized multiple emulsions or particles with a good control over sizes and shapes, as well as to provide a convenient data acquisition platform dedicated to slow or rather fast chemical reactions, i.e., from hours to a few minutes. High-pressure resistant devices were recently fabricated and used to generate stable droplets from pressurized fluids such as supercritical fluid-liquid systems. We believe that supercritical microfluidics is a promising tool to develop sustainable processes in chemistry.

When Solids Stop Flow Chemistry in Commercial Tubing

“…Seed crystals might not necessarily be removed via solvent injections, which would render fluoropolymer tubing inappropriate for subsequent experiments. Gaseous diffusions through porous fluoropolymer tubing have motivated the design of high-pressure devices when supercritical conditions exist [31]. Fluoropolymers such as PFA, FEP, and PEEK™ are not ultraviolet (UV) transparent, which potentially limits their use for the study of intrinsic photocatalytic kinetics [17a].…”

Path selection rules for droplet trains in single-lane microfluidic networks

“…For monophasic Newtonian flows, this problem has a unique solution easily derived using the analogy between fluidic networks and electric circuits mentioned above. For two-phase flows however, e.g flows in (droplet-based) digital microfluidic applications [5,6], strong nonlinearities arise and the problem becomes challenging. Indeed, the transport of discrete elements or information through networks, such as droplet traffic in single-lane microchannels having lateral dimensions comparable to the drop size, road traffic [7], blood microcirculation [8], and cell signaling [9], are all regulated by time-delayed feedback and nonlinear couplings.…”

Thermal analysis of droplet flow: Numerical, analytical and experimental investigations

“…In particular, for reaction engineering purposes, the use of segmented flows has increased in popularity in recent years [1,2,3]. In addition, the fluid mechanics and hydrodynamics of such miniaturized flows have been studied for both gas−liquid applications [4,5,6] and liquid−liquid applications [7,8].…”