Three-Fluid Sequential Micromixing-Assisted Nanoparticle Synthesis Utilizing Alternating Current Electrothermal Flow

Abstract

Multiple micromixing in a controlled sequence is an essential process for complex chemical synthesis of functional nanoparticles with desired physicochemical properties. Herein, we developed a unique sequential micromixing-assisted nanoparticle synthesis platform utilizing alternating current electrothermal flow (ACET). A two-fluid micromixer comprised with pairs of staggered asymmetric electrodes was first designed and characterized by joint numerical simulations and experiments to obtain the optimized electrode configuration within a straight channel. On this basis, an extra pair of symmetric electrodes was added at the main channel entrance to form a three-fluid sequential micromixer. The middle fluid would first mix with the side fluids through the symmetric ACET microvortex pair in the upstream region and then realize the side fluid mixing by the asymmetric ACET microvortex in the downstream region. Rapid and complete mixing in a short channel was observed for a relatively high flow velocity up to 7 mm/s at an AC signal of 27.5 V and 1 MHz. Sequential micromixing was achieved by flexibly adjusting the volume of each fluid and the AC voltage within the three-fluid mixer. Both the two-fluid mixing process and the three-fluid mixing process were applied to synthesize the Co−Fe Prussian blue analogue nanoparticles. In comparison with two-fluid mixing, three-fluid sequential mixing offers nanoparticles with higher dispersion, controlled particle morphology, and more regular shapes. Therefore, the ACET flow-based sequential micromixing strategy can be an alternative for complex chemical and biochemical reactions.

Intelligent control of nanoparticle synthesis through machine learning

“…They can achieve instantaneous homogeneous mixing of materials and efficient heat transfer, so many reactions that cannot be achieved in conventional reactors can be achieved in microreactors. 24,25 Nanoparticles have become one of the most important frontier applications in the development of modern analytical chemistry. Due to their unique optical, electrical, thermal, chemical and mechanical properties, they have a wide range of applications in many fields of analytical chemistry such as chromatography, electrochemical analysis, spectroscopy, imaging analysis, vital analysis, pharmaceutical analysis, etc., and especially they play an important role in enhancing the sensitivity, selectivity and analytical speed of analytical methods.…”

“…They can achieve instantaneous homogeneous mixing of materials and efficient heat transfer, so many reactions that cannot be achieved in conventional reactors can be achieved in microreactors. 24,25…”

Controllable Fabrication of Molecularly Imprinted Microspheres with Nanoporous and Multilayered Structure for Dialysate Regeneration

“…The PDMS chip was fabricated by standard photolithography and bonded using O 2 plasma activation [20,21]. The width and height of the channel were designed to be 1000 µm and 245 µm, respectively.…”

Design and Evaluation of Three-Dimensional Zigzag Chaotic Micromixers for Biochemical Applications

“…Over the past decades, microfluidics has attracted considerable attention in diverse areas like wearable biomarker sensing, − cell culture technologies, , and organic synthesis. , Recently, microfluidic devices have even been applied in COVID-19 diagnosis. , Unlike conventional batch reactors and analysis platforms, microfluidic devices have distinct advantages including high efficiency of heat and mass transfer, lower sample and reagent consumption, and integration of synthetic processes with analysis techniques (i.e., micrototal analysis system, μTAS) . However, high-efficiency micromixing in the low Reynolds number range ( Re < 100) remains as an essential challenge in microfluidics, especially for applications in chemical synthesis , and reaction kinetic studies. , On the macro scale, fast mixing of conventional working fluids can be accomplished with the aid of turbulent flow. However, miniaturization of microfluidic systems brings about unfavorable laminar flow and a molecular-diffusion-dominant mass transport mechanism, which is detrimental for micromixing.…”

“…To solve this problem, micromixers were created and can be classified as active and passive mixers according to energy input . Active mixers utilize external energy sources to facilitate mixing such as electric, magnetic, and acoustic fields. ,− Conversely, passive mixers only need pressure to drive the flow and prominently depend on geometry or surface modification of microchannels for mixing enhancement. In general, passive mixers are easy to fabricate and integrate and suitable for disposable utilizations but hard to control externally by users during working, while active mixers usually take great efforts to integrate the microfluidic device with an external power component.…”