Cavitation behavior and mixing performance of antisolvent precipitation process in an ultrasonic micromixer

Abstract

A facile and robust ultrasonic micromixer was developed to intensify antisolvent precipitation via ultrasonic cavitation. The gas supersaturation created from solventantisolvent mixing was found to be a novel driving force which facilitated the generation of cavitation bubbles (CBs). Instead of being attached on the channel wall, numerous CBs translated across the microchannel at a speed up to 1.7 m/s, inducing intense transverse flow over the cross-section. The unique cavitation behavior enabled rapid mixing (mixing time 15-45 ms at 30 W) of solvent-antisolvent over wide Reynolds number range (70-500) and flow rate ratio (5:1-2:3), providing better operability for antisolvent precipitation. The effects of ultrasonic power, total flow rate, flow rate ratio, and solvent on cavitation behavior and mixing performance were quantitatively studied. Finally, the potential of the ultrasonic micromixer as a new tool for antisolvent precipitation was demonstrated by synthesizing size-controllable and monodisperse polymeric nanoparticles in a high-throughput and reproducible manner.

Ultrasonic Enhanced Continuous Crystallization: Induction Time and Process Control

“…This process was recorded by using a high-speed camera (Phantom M310, Vision Research). The details of the ultrasonic reactor are available in our previous research . In continuous crystallization, it is difficult to distinguish the nucleation and crystal growth processes.…”

“…This benefit originated from the reduced mixing time between the solvent and antisolvent. Liu et al 39 found that the mixing time of ethanol and water could be shortened from 130 to 50 ms as the ultrasonic power increased from 5 to 30 W. The phenomenon of narrow particle size distribution resulting from flash mixing has been widely reported in various fields, such as precipitation, crystallization, and material synthesis. 46−48 Under the experimental conditions, the ASA crystal size varied in the range of 12.2−40.1 μm, which was smaller than that obtained in conventional equipment.…”

“…The details of the ultrasonic reactor are available in our previous research. 39 In continuous crystallization, it is difficult to distinguish the nucleation and crystal growth processes. Therefore, we applied ultrasound to fluids in both static (with the recording frame of 20000 fps, Figure 5) and flowing (1000 fps, Figure 6) states.…”

“…After applying ultrasound, the cavitation bubbles disturbed the fluid layer and accelerated the fluid mixing. During the crystallization, the first step was the mixing of solvent and antisolvent, which has been shown in our previous study that the mixing time of the same system was less than 200 ms. 39 Upon mixing, crystals began to precipitate around the cavitation bubbles as the ultrasound continued (t = 597 ms). At this stage, the appearance of crystals reduced the light transmission of the solution, and there were apparent shadows around the bubbles (t = 597 ms, green markers in Figure 5b).…”

Measurement and Model Evaluation of Solubility of 2-(4-tert-Butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole in Different Organic Solvents at Various Temperatures

“…According to the Ostwald–Freundlich equation, decreasing the particle size of organic materials further to the nanorange has exhibited higher solubility in poor solvents, − enabling the applications of high-performance small molecules as ink materials for printing processes in optoelectronic devices. The solubility of materials in various solvents serves as the basis for the solvent–antisolvent method, which is the most straightforward and commonly used approach for preparing nanoparticles. − …”