Damian Zaremba, M.Sc., Eng.

Department of Biosystems and Soft Matter (ZBiMM)
Division of Modelling in Biology and Medicine (PMBM)
position: doctoral student
telephone: (+48) 22 826 12 81 ext.: 161
room: 311
e-mail: dzaremba

Recent publications
1.Blonski S., Zaremba D., Jachimek M., Jakiela S., Wacławczyk T., Korczyk P.M., Impact of inertia and channel angles on flow distribution in microfluidic junctions, MICROFLUIDICS AND NANOFLUIDICS, ISSN: 1613-4982, DOI: 10.1007/s10404-020-2319-6, Vol.24, No.14, pp.1-15, 2020
Abstract:

In the present paper, we provide evidence of the vital impact of inertia on the flow in microfluidic networks, which is disclosed by the appearance of nonlinear velocity–pressure coupling. The experiments and numerical analysis of microfluidic junctions within the range of moderate Reynolds number (1 < Re < 250) revealed that inertial effects are of high relevance when Re > 10. Thus, our results estimate the applicability limit of the linear relationship between the flow rate and pressure drop in channels, commonly described by the so-called hydraulic resistance. Herein, we show that neglecting the nonlinear in their nature inertial effects can make such linear resistance-based approximation mistaken for the network operating beyond Re < 10. In the course of our research, we investigated the distribution of flows in connections of three channels in two flow modes. In the splitting mode, the flow from a common channel divides between two outputs, while in the merging mode, streams from two channels join together in a common duct. We tested a wide range of junction geometries characterized by parameters such as: (1) the angle between bifurcating channels (45°, 90°, 135° and 180°); (2) angle of the common channel relative to bifurcating channels (varied within the available range); (3) ratio of lengths of bifurcating channels (up to 8). The research revealed that the inertial effects strongly depend on angles between the channels. Additionally, we observed substantial differences between the distributions of flows in the splitting and merging modes in the same geometries, which reflects the non-reversibility of the motion of an inertial fluid. The promising aspect of our research is that for some combinations of both lengths and angles of the channels, the inertial contributions balance each other in such a way that the equations recover their linear character. In such an optimal configuration, the dependence on Reynolds number can be effectively mitigated.

Affiliations:
Blonski S.-IPPT PAN
Zaremba D.-IPPT PAN
Jachimek M.-IPPT PAN
Jakiela S.-other affiliation
Wacławczyk T.-Wroclaw University of Science and Technology (PL)
Korczyk P.M.-IPPT PAN
2.Korczyk P.M., van Steijn V., Błoński S., Zaremba D., Beattie D.A., Garstecki P., Accounting for corner flow unifies the understanding of droplet formation in microfluidic channels, Nature Communications, ISSN: 2041-1723, DOI: 10.1038/s41467-019-10505-5, Vol.10, No.1, pp.2528-1-9, 2019
Abstract:

While shear emulsification is a well understood industrial process, geometrical confinement in microfluidic systems introduces fascinating complexity, so far prohibiting complete understanding of droplet formation. The size of confined droplets is controlled by the ratio between shear and capillary forces when both are of the same order, in a regime known as jetting, while being surprisingly insensitive to this ratio when shear is orders of magnitude smaller than capillary forces, in a regime known as squeezing. Here, we reveal that further reduction of—already negligibly small—shear unexpectedly re-introduces the dependence of droplet size on shear/capillary-force ratio. For the first time we formally account for the flow around forming droplets, to predict and discover experimentally an additional regime—leaking. Our model predicts droplet size and characterizes the transitions from leaking into squeezing and from squeezing into jetting, unifying the description for confined droplet generation, and offering a practical guide for applications.

Affiliations:
Korczyk P.M.-IPPT PAN
van Steijn V.-Delft University of Technology (NL)
Błoński S.-IPPT PAN
Zaremba D.-IPPT PAN
Beattie D.A.-University of South Australia (AU)
Garstecki P.-Institute of Physical Chemistry, Polish Academy of Sciences (PL)
3.Zaremba D., Błoński S., Marijnissen M.J., Korczyk P.M., Fixing the direction of droplets in a bifurcating microfluidic junction, MICROFLUIDICS AND NANOFLUIDICS, ISSN: 1613-4982, DOI: 10.1007/s10404-019-2218-x, Vol.23, pp.55-1-18, 2019
Abstract:

We present a novel type of microfluidic bifurcating junctions which fixes the droplet’s route. Unlike in regular junctions, where a droplet chooses one of two outputs depending on the (often instantaneous) flow distribution, our modifications direct droplets only to one preferred outlet. As we show, this solution works properly regardless of the variations of flow distribution in a wide range of its amplitude. Such modified junctions allow for the encoding of the droplet’s traffic in the geometry of the device. We compare in a series of experiments different junctions having channels of uniform square cross section. Our observations revealed that a small, local modification of the junction in the form of an additional shallow slit imposes a significant consequence for the flow of droplets at an entire microfluidic network’s scale. Another interesting and helpful feature of these new junctions is that they keep the integrity of long droplets, unlike regular junctions, which tend to split long droplets. Our experimental investigations revealed a complex transformation of the long droplet during its transfer through the modified junction. We show that this transformation resembles the Baker’s transform and can be used for the enhancement of mixing inside the droplets. Finally, we show two examples of microfluidic devices where the deterministic character of these modified junctions is utilized to obtain new, non-trivial functionalities. This approach can be used for the engineering of microfluidic devices with embedded procedures replacing active elements like valves or magnetic/electric fields.

Keywords:

Droplet, Microfluidics, Two-phase, Manipulations

Affiliations:
Zaremba D.-IPPT PAN
Błoński S.-IPPT PAN
Marijnissen M.J.-IPPT PAN
Korczyk P.M.-IPPT PAN
4.Zaremba D., Błoński S., Jachimek M., Marijnissen M.J., Jakieła S., Korczyk P.M., Investigations of modular microfluidic geometries for passive manipulations on droplets, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/119068, Vol.66, No.2, pp.139-149, 2018
Abstract:

Multiple pipetting is a standard laboratory procedure resulting in the compartmentalisation of a liquid sample. Microfluidics offers techniques which can replace this process by the use of tiny droplets. Passive manipulation on droplets is an interesting and promising approach for the design of microfluidic devices which on one hand are easy-to-use and on the other, execute complex laboratory procedures. We present a comprehensive study of the geometry of microfluidic components which encode different operations on droplets into the structure of the device. The understanding of hydrodynamic interactions between the continuous flow and a droplet travelling through confined space of nontrivial microfluidic geometries is crucial for a rational and efficient design of new generation of modular microfluidic processors with embedded instructions.

Keywords:

microfluidics, two-phase flows, droplets

Affiliations:
Zaremba D.-IPPT PAN
Błoński S.-IPPT PAN
Jachimek M.-IPPT PAN
Marijnissen M.J.-IPPT PAN
Jakieła S.-Institute of Physical Chemistry, Polish Academy of Sciences (PL)
Korczyk P.M.-IPPT PAN