Continuous-flow lithography for high-throughput microparticle synthesis

Abstract

Precisely shaped polymeric particles and structures are widely used for applications in photonic materials, MEMS, biomaterials and self-assembly. Current approaches for particle synthesis are either batch processes or flow-through microfluidic schemes that are based on two-phase systems, limiting the throughput, shape and functionality of the particles. We report a one-phase method that combines the advantages of microscope projection photolithography and microfluidics to continuously form morphologically complex or multifunctional particles down to the colloidal length scale. Exploiting the inhibition of free-radical polymerization near PDMS surfaces, we are able to repeatedly pattern and flow rows of particles in less than 0.1 s, affording a throughput of near 100 particles per second using the simplest of device designs. Polymerization was also carried out across laminar, co-flowing streams to generate Janus particles containing different chemistries, whose relative proportions could be easily tuned. This new high-throughput technique offers unprecedented control over particle size, shape and anisotropy.

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

“…24(A)). Polymerization near the PDMS channel is inhibited thanks to the high O 2 permeability of PDMS [260], which avoids clogging of the channel. The non-polymerized monomer flow basically acts as the carrier phase for the polymerized particles.…”

“…The shapes and resolution of particles ( Fig. 24(B-D)) achieved with flow lithography techniques [259][260][261][262][263][264][265][266] are certainly unmatched by any other technique. …”

Fabrication of Hydrogel Particles of Defined Shapes Using Superhydrophobic‐Hydrophilic Micropatterns

“…[8][9][10][11][12] The Doyle group developed methods to generate hydrogel microparticles with specific shapes using continuous flow or stopflow lithography. 13 A droplet-based microfluidic system was proposed to construct alginate gel beads encapsulating cells. 14 Cell-encapsulating hydrogel particles have recently been used in several fields such as 3D cell culture and in vitro micro-physiological models.…”

Stop flow lithography in perfluoropolyether (PFPE) microfluidic channels

“…The current SFL protocol has several requirements in device construction 1,2 . (1) The channel material should be compatible 40 with soft lithography to allow rapid prototyping of channels with various geometries.…”

“…(1) The channel material should be compatible 40 with soft lithography to allow rapid prototyping of channels with various geometries. SFL devices have been fabricated with multiple inlet pathways or layered channels to create structured micro-flows for the synthesis of chemically patterned particles [1][2][3][4][5][6][7][8] .…”