Droplet-Based Microreactor

Through years of development, the portfolio of applications of droplet-based microreactors has expanded from chemical kinetics to a wide spectrum of applications including protein crystallization [10, 67, 96-99] and modeling complex reaction networks [100-104]. Interfacial reaction at the oil/water interface has also been explored for chemical synthesis [105]. Another interesting area is using droplets as highly effective reaction system to prepare nanoparticles [94, 106-108]. 

Capillary reactor Droplet micromixer Droplet-based microreactor... 

There are two basic platforms for droplet microreactors the planar platform and the in-channel continuous platform. In a planar platform, the droplet can move freely on a planar surface, while the motion of the droplet in an in-channel continuous platform is restricted by microchannels. The actuation of droplets in a planar platform is based on nonmechanical concepts such as electrowettmg, thermocapillary forces, and magnetic forces. Most in-channel... 

Droplet Microreactor, Fig. 1 Droplet microreactor based on actuation by electrowetting, (a) Device concept, (b) The liquid is pulled in by activating the two electrodes on the right. When the middle electrode is turned off, surface tension breaks up the droplet, allowing precise... 

Droplet Microreactor, Fig. 2 Droplet microreactor based on thermocapillary actuation, (a) Without a temperature gradient, the droplet is at equilibrium and does not move, (b) If heater 1 is on, the induced temperature gradient propels the droplet owing to the difference in surface stress between the sides of the droplet, (c) If the droplet moves out of the temperature field of heater 1, heater 2 is activated to propel the droplet further... 

One of the powerful techniques for obtaining the ultrafine particles is based on the use of microemulsions as microreactors in order to control the growth of the particles [80, 81]. For the purpose of the method described for obtaining ultrafine particles, water-in-oil (w/o) microemulsions used are formed by nanodroplets of water dispersed in oil. The size of the microemulsion droplets can be modified in the range 5-50 nm by varying the relation of the components of the microemulsion (e.g., changing W = [water]/[stabilizer] in the recipe) or by varying the microemulsion... 

Figure 7.10 Schematic of a capillary-based droplet microreactor for the continuous synthesis of MOF hollow microsphere. (Reproduced from Ref. [78].)...

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