Split And Recombine Research Articles

Controlled preparation of curcumin nanocrystals by detachable stainless steel microfluidic chip

Microfluidic technology has not been extensively utilized in nanocrystals manufacture, although it has been used in the production of liposomes and LNPs. This is mainly due to concerns including blockage of narrow pipes and corrosion of organic solvents on chips. In this study, a detachable stainless steel microfluidic chip with split-and-recombine (SAR) structure was engraved and used to prepare curcumin nanocrystal suspensions by a microfluidic-antisolvent precipitation method. A simulation study of the mixing activities of three chip structures was conducted by COMSOL Multiphysics software. Then the curcumin nanocrystals preparation was optimized by Box-Behnken design to screen different stabilizers and solvents. Two curcumin nanocrystals formulations with an average particle size of 59.29 nm and 168.40 nm were obtained with PDIs of 0.131 and 0.058, respectively. Compared to curcumin powder, the formulation showed an increase in dissolution rate in 0.1 M HCL while pharmacokinetic study indicated that Cmax was increased by 4.47 and 3.14 times and AUC0-∞ were 4.26 and 3.14 times greater. No clogging or deformation of the chip was observed after long usage. The results demonstrate that the stainless steel microfluidic chips with SAR structure have excellent robustness and controllability. It has the potential to be applied in GMP manufacturing of nanocrystals.

Local analysis of micro mixing for the Villermaux-Dushman protocol by using the imaging UV-Vis spectroscopy

The Villermaux-Dushman protocol with UV-Vis analytics is an established tool to characterize the global micro mixing performance in process equipment. The local mixing process is described by a micro mixing model (incorporation model), originally designed for turbulent flows. The novel imaging UV-Vis spectroscopy used in this work uncovers locally resolved micro mixing phenomena in a laminar split-and-recombine (SAR) mixer unit manufactured from selective laser-induced etching (SLE). The local absorbance is recorded with a high spatial resolution camera through a telecentric lens and post-processed into local concentration fields of components. The method unveils discrepancies of the micro mixing time determined from the conventional incorporation model in laminar flow and the locally recorded mixing process. The micro mixing time rather needs to be seen as a mean micro mixing time instead. Furthermore, the spatial information obtained by the imaging UV-Vis spectroscopy gives insight into local micro mixing and selectivity, yielding new approaches to equipment optimization.

DESIGN AND MIXING PERFORMANCE OF PASSIVE MICROMIXERS: A CRITICAL REVIEW

This study extracts and reports notable findings on passive micromixers by conducting an exhaustive review of designs, their features, and mixing performance. The study has covered the relevant articles on passive micromixers published from 2010 to 2020. The analysis of filtered and selected articles sums up passive micromixers into four categories: designed inlets, designed mixing-channel, lamination-based, and flow obstacles-based. The prominent mixing channel categories identified in the study are split-and-recombine (SAR), convergent-divergent (C-D), and mixed (SAR, C-D, and others). Moreover, differences in mixing channel designs, number of inlets, and evaluation methods have been used in comparing the mixing performance of passive micromixers. The SAR and the obstacles-based micromixers were found to outperform the others. The designs covered in the present review show significant improvements in the mixing index. However, these studies were conducted in an isolated environment, and most of the time, their fabrication and device integration issues were ignored. The assortment and critical analysis of micromixers based on their design features and flow parameters will be helpful to researchers interested in designing new passive micromixers for microfluidic applications.

Modeling and simulation of a split and recombination-based passive micromixer with vortex-generating mixing units

As a state-of-the-art technology, micromixers are being used in various chemical and biological processes, including polymerization, extraction, crystallization, organic synthesis, biological screening, drug development, drug delivery, etc. The ability of a micromixer to perform efficient mixing while consuming little power is one of its basic needs. In this paper, a passive micromixer having vortex-generating mixing units is proposed which shows effective mixing with a small pressure drop. The micromixer works on the split and recombination (SAR) flow principle. In this study, four micromixers are designed with different arrangements of mixing units, and the effect of the placement of connecting channels is evaluated in terms of mixing index, pressure drop, and mixing performance. The channel width of 200 μm, height of 300 μm, and size of mixing units are maintained constant for all the micromixers throughout the evaluation process. The numerical simulation is performed for the Reynolds number (Re) range of 0.1–100 using Comsol Multiphysics software. By categorizing the flow patterns into three regimes based on the range of Re, the fluid flow throughout the length of the micromixer is visualized. The micromixer with dislocated connecting channels provides a satisfactory result with the mixing index of 0.96 and 0.94, and the pressure drop of 2.5 Pa and 7.8 kPa at Re = 0.1 and Re = 100 respectively. It also outperformed the other models in terms of the mixing performance. The proposed micromixer might very well be used in microfluidic devices for a variety of analytical procedures due to its straightforward construction and outstanding performance.

Numerical Simulation of Mixing Characteristics in a Split-and-Recombine Microchannel

The mixing efficiency in microdevices is limited by laminar flow. For passive mixing, the structure of micromixer determines its mixing performance. A novel micromixer with a self-designed repetitive SAR (split-and-recombine) mixing element was carried out and investigated in the present work. The number of mixing elements for simulation was confirmed primarily. Based on the established model, the flow and geometric parameters in this micromixer were discussed systematically by numerical simulation and evaluated by mixing index. Furthermore, the mixing performance of SAR micromixer was compared with conventional T-shaped micromixer for Reynolds numbers ranging from 0.05 to 960. Finally, we concluded that the novel SAR micromixer revealed high performance of mixing due to the enhanced convection. In addition, its input power was similar to that of T-shaped micromixer, which provided the possibility for future industrial applications.

Design and High-Resolution Analysis of an Efficient Periodic Split-and-Recombination Microfluidic Mixer.

We developed a highly efficient passive mixing device based on a split-and-recombine (SAR) configuration. This micromixer was constructed by simply bonding two identical microfluidic periodical open-trench patterns face to face. The structure parameters of periodical units were optimized through numerical simulation to facilitate the mixing efficiency. Despite the simplicity in design and fabrication, it provided rapid mixing performance in both experiment and simulation conditions. To better illustrate the mixing mechanism, we developed a novel scheme to achieve high-resolution confocal imaging of serial channel cross-sections to accurately characterize the mixing details and performance after each SAR cycle. Using fluorescent IgG as an indicator, nearly complete mixing was achieved using only four SAR cycles in an aqueous solution within a device’s length of less than 10 mm for fluids with a Péclet number up to 8.7 × 104. Trajectory analysis revealed that each SAR cycle transforms the input fluids using three synergetic effects: rotation, combination, and stretching to increase the interfaces exponentially. Furthermore, we identified that the pressure gradients in the parallel plane of the curved channel induced vertical convection, which is believed to be the driving force underlying these effects to accelerate the mixing process.

A comparative study: conventional and modified serpentine micromixers

Abstract The study of flow and mixing dynamics for conventional micromixers as well as micromixers with split and recombine (SAR) units has been carried out using laminar and transport diluted physics modules. Initially, a pilot numerical analysis was done for the basic Y-shaped curved, rectangular and triangular serpentine micromixers. Later, SAR units have been added to these basic designs and the effect of SAR units on the performance characteristics viz., mixing index, pressure drop, performance index and pumping power has been studied. In-depth qualitative analysis was also carried out to visualize the flow and mixing dynamics for the Reynolds number in the range from 0.1–50. The study results revealed that the square shaped chambers and circular obstacle based rectangular serpentine micromixer (SCCO-RSM) demonstrated better performance as compared to the other designs. The proposed micromixer is the better candidate for microfluidics applications such as Lab-On-a-Chip (LOC), Micro-Total-Analysis-Systems (µTAS) and Point of Care Testing (POCT), etc.

Performance evaluation of a 3D split-and-recombination micromixer with asymmetric structures

Micromixers are widely used in lab-on-a-chip devices for analytical chemistry, bioengineering, and biomedicine to achieve rapid mixing and analysis of samples. However, the existing micromixers are mostly two-dimensional structures with low mixing efficiency. Even three-dimensional (3D) micromixers with complex structures have low mixing efficiency in the low Reynolds number range. In this paper, a 3D split-and-recombination (SAR) micromixer inspired by the horseshoe transform principle is proposed to further improve the mixing efficiency. There 3D SAR micromixers with different subchannel sizes were designed and tested in the Reynolds numbers range of 0.1–100. The optimal size of the micromixer was revealed through computational fluid dynamics simulations and experimental test results. A minimum mixing index of 91% is achieved in the range of Reynolds numbers from 0.1 to 100. Especially, for Re ⩾ 20, the mixing index is higher than 99%. The results obtained indicate that this 3D SAR micromixer with an asymmetric structure shows a satisfactory choice in the fluid mixing process of microfluidic systems, and has a potential application in the field of microchip-based biochemical analysis.

Gas-liquid hydrodynamics with different liquid viscosities in a split-and-recombine microchannel

Split-and-recombine (SAR) technology has shown great potential in the passive intensification of mass transfer. However, the gas-liquid flow is rarely encountered in the SAR microdevices. In this work, the flow regime, void fraction, and pressure drop of gas-liquid flow were experimentally studied in a common SAR microchannel designed with a curved divergence-convergence channel and rectangular obstacles. Parameter studies were conducted by varying the flow rates of nitrogen/glycerol aqueous solutions and glycerol contents. Four flow regimes, namely, total breakup, partial breakup, abnormal breakup, and annular flow are observed with a high-speed camera. The flow map and correlations to predict the regime transitions are presented based on the liquid-phase Capillary number (0.0022-1.016) and gas/liquid rate (0.5-5). Furthermore, the modified frictional factor is correlated with Capillary and Reynolds numbers based on the flow regimes. Overall, the SAR microchannel is a promising candidate as the high-efficient gas-liquid contactor in terms of mass transfer rate, product selectivity, and energy efficiency for highly viscous liquids. A reasonable match of bubble length and the number of SAR units for the total breakup of bubbles is required. This study can contribute to the design, optimization, and regulation of the SAR microchannel for gas-liquid flows.

A novel design for split-and-recombine micromixer with double-layer Y-shaped mixing units

A novel split-and-recombine (SAR) micromixer with Y-shaped mixing units is proposed. The two sets of Y-shaped units are distributed periodically and in opposite directions. The micromixer has better mixing performance and smaller pressure loss due to the three-dimensional Y-shaped structure, splitting recombination, and chaotic convection mechanism. First, based on the finite element theory, with the mixing index and pressure loss as the objective function, the software COMSOL was used to simulate and analyze the structure parameters and performance of the micromixer. Then, a prototype was manufactured, and experimental platforms were set up in the lab. Finally, the color reaction and silver nanoparticle synthesis experiments were carried out to characterize and verify that the micromixer is feasible. Simulation and experimental results show that, as an important structural parameter of the micromixer, the channel aspect ratio φ has a great impact on its mixing performance and pressure loss. When the aspect ratio φ = 0.5, the micromixer has excellent overall performance; With the increase of the Reynolds number (Re =0.5–100), the mixing index tends to decrease and then increase, while the pressure loss gradually increases. It has a mixing index of 0.966 at Re = 5, and the mixing index reaches 0.9992 at Re = 100. The pressure loss ∆P is less than 350 Pa through seven Y-shaped units at Re = 100; The micromixer enables to obtain uniform and efficient color reactions and to synthesize silver nanoparticles with good size, morphology, and monodispersity. The micromixer has broad application prospects in chemical synthesis, biochemical analysis, and biomedicine.

Bubble dynamics and mass transfer enhancement in split–and–recombine (SAR) microreactor with rapid chemical reaction

In this study, a split–and–recombine (SAR) microreactor which is composed of convergent–divergent arc channel and rectangular obstacles was designed, and its enhancement characteristics in gas–liquid rapid chemical absorption system were explored. In the SAR microreactor, the deformation, splitting, stretching and breakup of bubbles are monitored by a high–speed camera. Accordingly, the bubble velocity pulsation caused by SAR structure is analyzed. The squeezing mechanism for bubble breakup located on the front surface of the obstacle is revealed. Two breakup patterns, namely complete and partial breakup, are observed, and the mass transfer performance is highly related to them. The mass transfer enhancement factor (Eka) of SAR structure increases with gas/liquid flow rate in complete breakup pattern while decreases in partial breakup pattern. The increase of gas–liquid flow rates and the number of SAR units, or slower reaction rate strengthens the velocity fluctuation and bubble breakup, resulting in an increase in Eka, with a maximum value of 2.74. Overall, the SAR microreactor performs comparable to Corning Advanced Flow Reactor in term of mass transfer energy efficiency. This work guides the application of SAR microreactor in rapid gas–liquid chemical reaction system.

A SAR Micromixer for Water-Water Mixing: Design, Optimization, and Analysis

A numerical investigation of the mixing performance and fluid flow in a new split and recombine (SAR) Y−Uβ micromixer is presented in this work. A parameter called connecting angle βis varied from 0° to 90° to analyze the effect on the SAR process and mixing performance. Thenumerical data shows that the SAR process strongly depends on the connecting angle (β) and maximum efficiency (93%) can be achieved when the value of β is 45°. The Y−U45° the mixer also offers higher efficiency and lower pressure drop than a known SAR ‘H−C’ mixer irrespective of Reynolds numbers. The split and recombine process, the influence of secondary flow, and pressure drop characteristics at various Reynolds numbers are also studied. In addition, mixing effectiveness is also computed, and among all examined mixers, Y−U45° is by far the best performing one.

CFD analysis of asymmetric mixing at different inlet configurations of a split-and-recombine micro mixer

In the scope of the ENPRO II initiative (Energy Efficiency and Process Intensification for the Chemical Industry), a major challenge of process intensification of polymer synthesis in continuous systems is fouling. Pre-mixing is a key aspect to prevent fouling and is achieved through milli and micro structured devices (Bayer et al. 1). While equal volume flow ratios are well investigated in milli and micro systems, asymmetric mixing tasks have received less attention. This paper investigates the dependency of mixing phenomena on different flow rate ratios and modified inlet geometries. A split-and-recombine (SAR) mixer is modified by means of an injection capillary to facilitate the asymmetric mixing task. Asymmetric volume flows of ratios between 1:15 and 1:60 are investigated; the velocity ratios range from 0.5 to 2. The setup is simulated with the Computational Fluid Dynamics (CFD) tool ANSYS®;Fluent. The species equation is solved directly without the use of micro mixing models. The simulation is validated by means of a concentration field in a mixing Tee using Laser-Induced Fluorescence (LIF) with a Confocal Laser Scanning Microscope (CLSM). The three dimensional flow structures and the mixing quality are analyzed as a measure for micro mixing. The calculated concentration fields show good agreement with the experimental results and reveal the secondary flow structures and chaotic advection within the channel. The injection of the small feed stream is found to be very efficient when drawn into the secondary structures, increasing the potential of diffusive mixing. CFD simulations help to understand and locate such structures and improve the mixing performance.

A new two-layer passive micromixer design based on SAR-vortex principles

Abstract Micromixers are key components of microfluidic systems for sample analysis, bioreactors, drug delivery, and many other applications. To date, numerous passive micromixer designs have been proposed. Among those, several designs with complex design structures have been demonstrated to be efficient. In the present work, the authors try to propose a new efficient design with low complexity in terms of fabrication. The new design is two-layer and is based on the split and recombination (SAR) and vortex mixing principles. It is suggested to fabricate the new design in polydimethylsiloxane (PDMS) using the soft lithography technique. This new design is chosen among three new designs simulated using the computational fluid dynamics (CFD) software ANSYS Fluent 17.0. The three new designs are named ND1, ND2, and ND3 and their mixing performances are evaluated numerically using mixing index (MI) and mixer effectiveness (ME) quantities at four different Reynolds (Re) numbers in the range of 0.1–100. Calculated values are compared with those obtained for the classical Y-shaped (CY) micromixer. Flow and mixing patterns are computed by solving the continuity, Navier–Stokes, and the convection–diffusion equations. CFD results for the CY micromixer are compared with available experimental and numerical data and reasonable agreement is observed. According to the results, ND3 has the highest performance (ME up to 36.86 percent/mm) among the investigated micromixer designs in the entire range of Re numbers. The maximum pressure drop (35099.9 Pa at Re = 100 for ND3) is still in the range of acceptable pressure drops reported in the literature. ND3 can be used as an efficient substitute for CY. Although ND3 is highly efficient (MI up to 99.52%) at Re numbers lower than 0.3 or higher than 50, its performance at the intermediate Re numbers (0.3 < Re < 50) is poor and unacceptable (MI as low as 44%). This can be simply improved by adding extra mixing units to provide adequate mixing also at the intermediate Re numbers.

CFD simulation of creeping flows in a novel split-and-recombine multifunctional reactor

Various mixing processes deal with the blending of viscous fluids at low Reynolds numbers. Some of the emerging trends rely on the use of either active or passive microstructures to achieve this task when highly viscous or fragile fluids are employed. The compactness of such mixers remains, however, a major challenge due to the long residence times required to achieve the desired outcome. Split-and-Recombine (SAR) mixers are a promising solution since they rely on a multi-lamination process to perform a series of baker’s transforms on the concentration profile.The current work is a numerical study that describes the hydrodynamic and mixing performance of a new topology of SAR mixers. This mixer is characterized by a double separation and recombination aimed at increasing the mixture homogeneity in a shorter distance. For this purpose, a finite element solver is used to compute the pressure drop, friction factor, concentration profile, and segregation scales for a viscous fluid in the creeping flow regime. The results are compared against two commonly used SAR mixers in the open literature. The findings show that the newly proposed mixer exhibits a superior performance through a better mixing quality at a lower energy consumption requirement.

Mixing Performance of a Cross-Channel Split-and-Recombine Micro-Mixer Combined with Mixing Cell.

A new cross-channel split-and-recombine (CC-SAR) micro-mixer was proposed, and its performance was demonstrated numerically. A numerical study was carried out over a wide range of volume flow rates from 3.1 μL/min to 826.8 μL/min. The corresponding Reynolds number ranges from 0.3 to 80. The present micro-mixer consists of four mixing units. Each mixing unit is constructed by combining one split-and-recombine (SAR) unit with a mixing cell. The mixing performance was analyzed in terms of the degree of mixing and relative mixing cost. All numerical results show that the present micro-mixer performs better than other micro-mixers based on SARs over a wide range of volume flow rate. The mixing enhancement is realized by a particular motion of vortex flow: the Dean vortex in the circular sub-channel and another vortex inside the mixing cell. The two vortex flows are generated on the different planes perpendicular to each other. They cause the two fluids to change their relative position as the fluids flow into the circular sub-channel of the SAR, eventually promoting violent mixing. High vorticity in the mixing cell elongates the flow interface between two fluids, and promotes mixing in the flow regime of molecular diffusion dominance.

Mixing Performance of a Cost-effective Split-and-Recombine 3D Micromixer Fabricated by Xurographic Method.

This paper presents experimental and numerical investigations of a novel passive micromixer based on the lamination of fluid layers. Lamination-based mixers benefit from increasing the contact surface between two fluid phases by enhancing molecular diffusion to achieve a faster mixing. Novel three-dimensional split and recombine (SAR) structures are proposed to generate fluid laminations. Numerical simulations were conducted to model the mixer performance. Furthermore, experiments were conducted using dyes to observe fluid laminations and evaluate the proposed mixer’s characteristics. Mixing quality was experimentally obtained by means of image-based mixing index (MI) measurement. The multi-layer device was fabricated utilizing the Xurography method, which is a simple and low-cost method to fabricate 3D microfluidic devices. Mixing indexes of 96% and 90% were obtained at Reynolds numbers of 0.1 and 1, respectively. Moreover, the device had an MI value of 67% at a Reynolds number of 10 (flow rate of 116 µL/min for each inlet). The proposed micromixer, with its novel design and fabrication method, is expected to benefit a wide range of lab-on-a-chip applications, due to its high efficiency, low cost, high throughput and ease of fabrication.

Mixing performance in Split-And-Recombine Milli-Static Mixers—A numerical analysis

Very low Reynolds number laminar flow in Split-And-Recombine (SAR) static mixers is numerically investigated by using a finite volume method. In these configurations, advective chaotic flow structures are created by the passive control of the flow, mimicking the baker’s transformation, through a series of flow splitting, rotations, and re-combinations that generate intertwined lamellar structures. This process leads to extra surface creation, which ultimately intensifies mass transfer. The main aim of this study is firstly to demonstrate the interest of this technique for enhancing mixing, while keeping pressure drops moderate, and secondly to optimize this type of geometry. For the latter stake, two different SARs, namely SAR1 (Gray’s configuration) and SAR2 (Chen’s configuration), are compared in terms of distributive and dispersive mixing and energy expenditures evaluated by the pressure drop. The enhancement effect of splitting/recombination is isolated through the comparison with a channel composed of small straight sections at right angle bends with alternate chiralities (referred as 3D-Flow), without splitting. A plain square-section channel is used as base-line reference geometry to assess the relative mixing efficiency of each configuration. Results show that the SAR technique is capable of enhancing mass transfer in creeping flows compared to non-splitting-flow mixers/exchangers, thus allowing a gain in residence time and mixer size for the same final results. Between the two SAR geometries, the superiority of Chen’s configuration regarding the relative mixing efficiency is demonstrated, with 83% mixing intensification, accompanied by a cost increase of 68% in the friction coefficient.

Flow field analysis of a passive wavy micromixer with CSAR and ESAR elements

The performance analysis of wavy micromixers with split and recombine (SAR) elements has been carried out. The two types of SAR elements viz. circular split and recombine elements and elliptical split and recombine elements are used to get benefit of SAR mechanism. The main concept in the proposed design is to enhance the interfacial area between the two fluids by creating a transverse flow and split and recombination of fluid flow streams with the help of SAR elements. The effects of balanced split and unbalanced split of SAR elements and operational parameter Reynolds number on the mixing index and pressure drop are evaluated. The COMSOL Multiphysics 5.0 is used for computational fluid dynamics analysis of micromixers. The analysis is carried out for balanced and unbalanced split of the mixing elements at various Reynolds numbers in the range of 0.1–75. The computation interfacial patterns on the planes perpendicular to the direction of fluid flow, mixing index and pressure drop are studied in depth. The results indicate that at inlet Reynolds number below 5, the mixing performance is diffusion dominated. However at Reynolds number greater than 5, the mixing index increases intensely due secondary flow and separation vortices, as well as SAR effect.

Manufacturing and Test of Split and Recombine Micromixers with a Variable Cross-Section

The methodology for manufacturing array of microdevices that features a varying cross-section is introduced towards the development of complex devices that are more prone to be adapted in-field. In this paper stereolithography or digital light, processing is assessed for developing asymmetric split-and-recombine micromixers that can be tested under a machine vision system. To test the proposed manufacturing methodology an array of 6 microdevices with a varying depth from 100 to 1000 micrometers were characterized using an Infinite Focus Measurement to verify the feasibility of the proposed methodology for a large range of length-to-depth ratios. Surface metrology showed that molds were produced within 4 to 10 mm of absolute deviational error. Split and Recombine (SAR) micromixers devices were manufactured employing microfabrication methods derived from the semiconductor industry to engrave polydimethylsiloxane (PDMS) such as photolithography, or to a lesser extent micromachining or laser ablation of other materials. However, these methodologies have several limitations; they are often expensive, require special infrastructure such as clean rooms and may have long production cycles for new designs. Moreover, devices are manufactured using a soft lithography technology that is limited to a singular cross-section depth. An Envisiontec Perfactory P3 Mini Multilens additive manufacturing equipment that uses a 60 mm lens system and with a work tray of 84 x 63 x 230 mm and with a pixel resolution of up to 50 μm for the used material. The equipment was loaded with a white Flex Series ABS resin characterized by a yield stress of 65MPa and a Young's modulus of 1772 MPa. An Otoflash pulse curing chamber from the same supplier with a wavelength between 300 and 700 nanometers, with a lamp of 11 watts of power and 10 pulses per second. An array of six assymetric asymmetric SAR micromixers (ASAR) were developed with a width of 1000 µm and a varying depth of 100, 250, 500, 750, 900 and 1000 µm for depth-to-width ratio of 1:10, 1:4, 1:2, 3:4, 9:10 and 1:1 respectively. For characterization of the molds, an Alicona Infinite Focus Measurement Machine has been employed for surface characterization. This device allows the acquisition of datasets at a high depth of focus similar to a Scanning Electronic Microscope. Infinite Focus Microscopy (IFM) has shown to be capable of capturing images with a lateral resolution down to 400 nm providing 3D datasets with very accurate results. For this work, each mold depth array element was measured twice for a total number of 36 samples. The molds were used to pour polydimethylsiloxane (PDMS) to produce the micromixing structures. A syringe pump and two plastic syringes were used to individually supply fluorescent particles and a solution of blue dye and distilled water through the micromixer inlets at same flow rate. A flow rate of 1 ml/min was applied to the microdevice to test the device sealing. Two machine vision setups were employed: an inverted microscope with a ultra high-speed camera and an inverted microfluidic microscope were implemented to evaluate used to assess the performance of a micromixer using the concentration field including parameters such as mean concentration (Cm), standard deviation (σ), coefficient of variation (CoV) or mixing index (M). Methodology for the production of an array of micromixers with a variable cross-section in a single step was successfully implemented. Figure 1