Nanomaterial synthesis within microflow devices

A microfluidic device is a continuously operating chemical reactor with one or more internal dimensions in the micrometer range. The physics of fluid flow in these miniaturized reactors has been radically altered compared with conventional batch reactors.

Since the early 2000s, researchers in nanomaterial synthesis have embraced this technology to better control the size, shape and reactivity of these nano-objects, with applications in a growing number of fields. Indeed, a large number of technological innovations and the design of materials produced in the 21st century will be influenced by the intrinsic structural properties offered by nanomaterials, ranging from chemical synthesis, to the development of consumer products (such as polymer-based nanocomposites in the transport sector), to energy supply and storage (such as polymer electrolyte membranes within fuel cells and lithium-ion batteries), or applications in the medical field.

This is justified by the large number of scientific papers published on the development of nanomaterials for applications in various fields over the past decade. More specifically, synthesized nanomaterials have been widely applied in nanocatalysis for :

• chemical synthesis ;

• hydrogen production;

• power generation ;

• energy storage.

Applications have also been developed in optronics, solar photovoltaics, gas detection, plasmonic display devices, and nanoparticle drug encapsulation to facilitate delivery to the human body.

In this article, after an introduction to the physical phenomena responsible for reactivity in microfluidic devices, a number of case studies are presented, detailing the various existing microfluidic technologies and their advantages and disadvantages. The importance of these devices for more detailed mechanistic studies is examined, and finally the problem of scaling up to industrial production is exemplified.