Handling of Polymer Particles in Microchannels

Abstract

This paper deals with solid-liquid operations in microchannels. Continuous operations on solids (modification of frequency, change of solvent, encapsulation) in order to handle polymer particles in microchannels are described in terms of the limits of operating conditions and their possible applications. A methodology to design and implement operations on polymer particles is presented here. It is applied for the generation of onion-like structures. A microdevice completely built with Plexiglas plates and fused silica capillaries is used. The device includes droplet generation, polymerization and microparticle flow manipulation. The particles manipulated are in the range of 70 to 200 microns with a very low index of polydispersity.

What are the needs for Process Intensification?

“…For instance, the work performed by (Marcati et al, 2010) including droplet generation, polymerization, and particles handling (solvent change or particles encapsulation in microchannels) has allowed to generate complex solid structures (such as onion-like structures) pictured in Figure 9, which exhibits the different sizes and shapes obtained according to the flow rate of TriPropylene Glycol DiAcrylate (TPGDA), as reactive diluent.…”

Particle Handling Techniques in Microchemical Processes

“…The isolation of particles that tend to agglomerate or stick to surfaces has been accomplished by the encapsulation of reactions within dispersed droplets, as highlighted in Figure 3(a,b). Protein crystals (Figure 3a), [67] or other insoluble compounds such as polymers (Figure 3b), [38,39] are limited in their interaction with microchannel surfaces in the presence of an immiscible barrier between the phases. Interestingly, immiscible gas-liquid interfaces [84][85][86] have been demonstrated as possible separation techniques; micron-sized particles accumulate at the lower surface-free-energy interfaces (see Figure 3c) [87][88][89].…”

Microbubbles as Heterogeneous Nucleation Sites for Crystallization in Continuous Microfluidic Devices

“…XFEL 14 . However, switching to microfluidics while solids are present in the system introduces the problem of clogging associated with small scale devices [15][16][17] . To overcome clogging, solid handling and controlled particle formation inside the microfluidic device are of utmost importance.…”

“…To overcome clogging, solid handling and controlled particle formation inside the microfluidic device are of utmost importance. Two-phase liquid-liquid segmented flow, has been successfully applied to prevent clogging of microchannels 11,15,18,19 , as encapsulating particles within dispersed droplets limits their interaction with the microchannel surface 17,20,21 .…”

“…In this respect, microfluidics represents a promising technology due to enhanced heat and mass transfer rates, − which, translated to particle generation, provide control of size, morphology, and composition. − Furthermore, continuous production of crystals on the microscale also potentially enables to link microreactors with novel crystal characterization techniques, e.g., X-ray free-electron laser (XFEL) . However, switching to microfluidics while solids are present in the system introduces the problem of clogging associated with small-scale devices. − To overcome clogging, solid handling and controlled particle formation inside the microfluidic device are of utmost importance. A two-phase liquid–liquid segmented flow has been successfully applied to prevent clogging of microchannels, ,,, as encapsulating particles within dispersed droplets limit their interaction with the microchannel surface. ,, …”