Coaxial air flow device for the production of millimeter-sized spherical hydrogel particles

Workamp, Marcel; Alaie, Sepideh; Dijksman, Joshua A.

doi:10.1063/1.4972587

Cited by 15 publications

(19 citation statements)

References 28 publications

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“…Due to the simplicity of hard sphere suspensions and availability of materials, RIMS studies are mostly done with plastic or glass particles [8,9,10], index matched with vis- cous and/or expensive liquids. However, spherical particles made out of hydrogel (or polyacrylamide gel) have become commercially available [14] and methods to custom produce them have been proposed [15]. Hydrogel as a material has the benefit that it is cheap, safe and easily index matched with a watery solution.…”

Section: Using Hydrogel Spheresmentioning

confidence: 99%

Refractive index matched scanning and detection of soft particles

Dijksman

Brodu

Behringer

2017

Review of Scientific Instruments

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We describe here how to apply the three-dimensional imaging technique of refractive index matched scanning to hydrogel spheres. Hydrogels are water based materials with a low refractive index, which allows for index matching with water-based solvent mixtures. We discuss here various experimental techniques required to handle specifically hydrogel spheres as opposed to other transparent materials. The deformability of hydrogel spheres makes their identification in three-dimensional images non-trivial. We will also discuss numerical techniques that can be used in general to detect contacting, non-spherical particles in a three-dimensional image. The experimental and numerical techniques presented here give experimental access to the stress tensor of a packing of deformed particles.

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Section: Using Hydrogel Spheresmentioning

confidence: 99%

Refractive index matched scanning and detection of soft particles

Dijksman

Brodu

Behringer

2017

Review of Scientific Instruments

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“…where u and r are the velocity and density of the owing liquid, respectively, C D is the drag coefficient, and A is the crosssectional area of the obstacle. 24,25 If the gas ow is certain, a smaller D 2 and D 3 could reduce the cross-sectional area of the annular gas ow channel and increase the velocity of gas, which is favorable for making smaller droplets. But, it's difficult for the DLP 3D printer to print a wall or clearance smaller than 300 mm.…”

Section: Design and Printing Of The Nozzlementioning

confidence: 99%

3D-printed air-blast microfluidic nozzles for preparing calcium alginate microparticles

Bao

et al. 2017

RSC Adv.

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Microfluidic technologies have emerged as a promising route for precision fabrication of uniform particles. Equipment required for a traditional microfluidic device manufacturing process is expensive and production efficiency is low. It's also difficult to separate a surfactant and continuous phase impurities from particles prepared by a liquid-liquid two-phase shear method. A novel air-blast microfluidic nozzle fabricated using low-cost and efficient 3D printing technology was proposed to prepare calcium alginate particles.Effects of control parameters and solution composition on particle diameters and homogeneity were systematically investigated. Results showed that inlet air pressure has the most significant impact. A nozzle with an outlet diameter of 300 mm can produce particles with diameters ranging from 360 mm to 2100 mm. Coefficients of variation (CV) range from 5.3% to 2.2%. For the same diameter particle prepared, a smaller nozzle outlet had a narrower particle diameter distribution and needed lower inlet air pressure. This method can be used to handle high viscosity solutions and high concentrations of solutions with insoluble solid particles. The prepared particles can be used in biological and pharmaceutical fields.

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“…We use a method described in detail elsewhere [11]. We use two different materials; gelatin and polyacrylamide (PAAm).…”

Section: Hydrogel Particlesmentioning

confidence: 99%

What is fluidity? Designing an experimental system to probe stress and velocity fluctuations in flowing suspensions

2017

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Abstract. We develop a method to investigate the microscopic origin of granular fluidity. We design a Couette cell in which we can probe the flow of soft hydrogel suspensions. As we drive the suspension with a rheometer, we have access to global flow characteristics. In addition, the Couette cell has been modified to have a transparent bottom and lid, allowing for imaging of suspension characteristics in transmission, for example flow fields. We can also use transmission imaging to probe local stresses in the suspension: we use hydrogel particles composed of gelatin, which through its photoelastic properties gives access to local stress fluctuations. We thus have access to all local microscopic variables that are relevant in the understanding of granular suspensions. We show here that our setup can indeed visualize stress fields inside the suspensions and perform flow field measurements in transmission mode. We compare the profiles of the gelatin suspension to that of a polyacrylamide hydrogel suspension, to assess robustness of observed phenomenology. We find that the flow profiles for both types of hydrogels are different; gelatin suspensions feature narrower and less rate-dependent flow profiles. We speculate on the origin of the observed difference by considering the frictional properties of the suspended particles.

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Coaxial air flow device for the production of millimeter-sized spherical hydrogel particles

Cited by 15 publications

References 28 publications

Refractive index matched scanning and detection of soft particles

Refractive index matched scanning and detection of soft particles

3D-printed air-blast microfluidic nozzles for preparing calcium alginate microparticles

What is fluidity? Designing an experimental system to probe stress and velocity fluctuations in flowing suspensions

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