Soft Matter and Complex Systems Seminar
2006/2007 | 2007/2008 | 2008/2009 | 2009/2010 | 2010/2011 | 2011/2012 | 2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2016/2017 | 2017/2018 | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025
2023-03-24 (Friday)
room 1.40, Pasteura 5 at 09:30 
Michał Bogdan (IChF PAN)Crystallization and topology-induced dynamical heterogeneities in soft granular clusters
Authors: Michał Bogdan, Mihir Durve, Leon Jurkiewicz, Sauro Succi, Jan Guzowski
Soft-granular media such as dense emulsions, foams or tissues tend to exhibit either fluid- or solid-like properties depending on the applied stresses. However, the internal dynamics of soft granular systems bound by closed interfaces is poorly understood, while it remains of significant interest in diverse fields ranging from material science (porous materials) and tissue engineering (granular bioinks) to developmental biology (embryos, organoids) and medicine (circulating tumor cell clusters). Here, we report the spontaneous occurrence of crystalline-like hexagonal structures within soft granular clusters which self-organize under external flow. We use a densely packed double emulsion as a model soft granular material to produce clusters of sizes of 20-40 grains (droplets). We find that, optimally, the crystallites emerge under weak flows, when the internal shear stresses slightly agitate the system allowing internal rearrangements. Excessive flows destroy the delicate crystalline structure and lead to constant internal recirculations, i.e., effective fluidization of the granular medium. Upon subjecting the clusters to cycles of constriction and relaxation/expansion, we also find differences between the behaviours of two groups of droplets: those within the inner part of the cluster and those at its rim, with the latter subjected to larger deformations and less frequent rearrangements, effectively acting as an elastic solid-like membrane around the inner fluid-like core. This structural-dynamical heterogeneity appears to be of purely topological origin and as such we expect it to remain universal in various types of soft granular clusters or jets including also cell aggregates, organoids or bioprinted tissues.
Soft-granular media such as dense emulsions, foams or tissues tend to exhibit either fluid- or solid-like properties depending on the applied stresses. However, the internal dynamics of soft granular systems bound by closed interfaces is poorly understood, while it remains of significant interest in diverse fields ranging from material science (porous materials) and tissue engineering (granular bioinks) to developmental biology (embryos, organoids) and medicine (circulating tumor cell clusters). Here, we report the spontaneous occurrence of crystalline-like hexagonal structures within soft granular clusters which self-organize under external flow. We use a densely packed double emulsion as a model soft granular material to produce clusters of sizes of 20-40 grains (droplets). We find that, optimally, the crystallites emerge under weak flows, when the internal shear stresses slightly agitate the system allowing internal rearrangements. Excessive flows destroy the delicate crystalline structure and lead to constant internal recirculations, i.e., effective fluidization of the granular medium. Upon subjecting the clusters to cycles of constriction and relaxation/expansion, we also find differences between the behaviours of two groups of droplets: those within the inner part of the cluster and those at its rim, with the latter subjected to larger deformations and less frequent rearrangements, effectively acting as an elastic solid-like membrane around the inner fluid-like core. This structural-dynamical heterogeneity appears to be of purely topological origin and as such we expect it to remain universal in various types of soft granular clusters or jets including also cell aggregates, organoids or bioprinted tissues.
2023-03-17 (Friday)
room 1.40, Pasteura 5 at 09:30
Magdalena Birowska (IFT UW)Magnetic fingerprints in structural, electronic and optical studies of 2D magnetic crystals
In recent years, 2D magnetic materials gained a lot of interest due to their potential optoelectronics applications [1]. The current research focuses on the study of the transition metal phosphorous tri-chalcogenides semiconductors (MPX3, M=1st row transition metals, X=chalcogenides), which are antiferromagnetic compounds exhibiting various magnetic orderings. These materials are stable in air and we predict that the excitonic binding energies are giant for these compounds [2]. In fact, that these materials are 2D magnets, allowing one to both study and use magnetism and optics, and their interplay, in a single stable material. There is no precedence of such a platform in the realm of conventional materials.
In this study, I will tackle a following scientific questions: what mechanism sustains the long-range AFM ordering, and whether the type of magnetic arrangement can be manipulated? In particular, I will present a comprehensive theoretical ab initio results of the electronic and optical properties of the series of MPX3 monolayers (M=Mn, Ni, Fe, Co, and X=S,Se), as well as the alloy systems with magnetic [3] and nonmagnetic substitution [4]. Finally, I highlight the importance of the structural anisotropy in this family of materials [5]. The aformentioned efficient engineering of the magnetism provides a suitable platform to understand the magnetism in thin samples.
[1] M. Gibertini, M. Koperski, A. F. Morpurgo, K. S. Novosolev, Nat. Nanotech. 14, 408 (2019).
[2] M. Birowska, P.E.F. Junior, J. Fabian, J, Kuntsmann, Phys. Rev. B 103, L121108 (2021).
[3] C.Autieri, G. Cuono, C. Noce, M. Rybak, K. M. Kotur, C. E. Agrapidis, K. Wohlfeld, M. Birowska, J. Phys. Chem. C 126, 6791 (2022).
[4] R. Basnet, K. Kotur, M. Rybak, C. Stephenson, S. Bishop, C. Autieri, M. Birowska, J. Hu, Phys. Rev. Research 4, 023256 (2022).
[5] A. K. Budniak, S. J. Zelewski, M. Birowska, T. Wozniak, T. Bendikov, Y. Kauffmann, Y. Amouyal, R. Kudrawiec, E. Lifshitz, Adv. Optical Mater. 2022, 2102489
In this study, I will tackle a following scientific questions: what mechanism sustains the long-range AFM ordering, and whether the type of magnetic arrangement can be manipulated? In particular, I will present a comprehensive theoretical ab initio results of the electronic and optical properties of the series of MPX3 monolayers (M=Mn, Ni, Fe, Co, and X=S,Se), as well as the alloy systems with magnetic [3] and nonmagnetic substitution [4]. Finally, I highlight the importance of the structural anisotropy in this family of materials [5]. The aformentioned efficient engineering of the magnetism provides a suitable platform to understand the magnetism in thin samples.
[1] M. Gibertini, M. Koperski, A. F. Morpurgo, K. S. Novosolev, Nat. Nanotech. 14, 408 (2019).
[2] M. Birowska, P.E.F. Junior, J. Fabian, J, Kuntsmann, Phys. Rev. B 103, L121108 (2021).
[3] C.Autieri, G. Cuono, C. Noce, M. Rybak, K. M. Kotur, C. E. Agrapidis, K. Wohlfeld, M. Birowska, J. Phys. Chem. C 126, 6791 (2022).
[4] R. Basnet, K. Kotur, M. Rybak, C. Stephenson, S. Bishop, C. Autieri, M. Birowska, J. Hu, Phys. Rev. Research 4, 023256 (2022).
[5] A. K. Budniak, S. J. Zelewski, M. Birowska, T. Wozniak, T. Bendikov, Y. Kauffmann, Y. Amouyal, R. Kudrawiec, E. Lifshitz, Adv. Optical Mater. 2022, 2102489
2023-03-10 (Friday)
room 1.40, Pasteura 5 at 09:30
D. Suwała, P. Śmieja, W. Noskowiak, D. Nowicka (FUW)Student Talks
On Friday 10 March 2023 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting short student presentations by:
Dominik Suwała (Industrial designed enzymes. How can we get there?)
Piotr Śmieja (Julia language for simulations and data analysis)
Wojciech Noskowiak (Turing patterns and their applications)
Dorota Nowicka (Physics of coffee brewing)
We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).
Dominik Suwała (Industrial designed enzymes. How can we get there?)
Piotr Śmieja (Julia language for simulations and data analysis)
Wojciech Noskowiak (Turing patterns and their applications)
Dorota Nowicka (Physics of coffee brewing)
We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).
2023-03-03 (Friday)
room 1.40, Pasteura 5 at 09:30
D. Woś, M. Czerepaniak, P. Zduńczyk, M. Sobolewski, F. Basiński (FUW)Student Talks
On Friday 3 March 2023 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting short student presentations by:
Dawid Woś (Modeling the growth of mineral dendrites)
Michał Czerepaniak (Correlation functions of arbitrary Brownian particles)
Piotr Zduńczyk (Heart rate variability)
Mikołaj Sobolewski & Franciszek Basiński (Temperature regulation and ventilation in termite mounds)
We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).
Dawid Woś (Modeling the growth of mineral dendrites)
Michał Czerepaniak (Correlation functions of arbitrary Brownian particles)
Piotr Zduńczyk (Heart rate variability)
Mikołaj Sobolewski & Franciszek Basiński (Temperature regulation and ventilation in termite mounds)
We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).
2023-01-27 (Friday)
room 1.40, Pasteura 5 at 09:30
Marilize Everts (University of Pretoria)Recent advancements in the fundamentals of single-phase internal heat transfer
Single-phase flow has been investigated from as early as 1883, yet research is still being conducted to improve our fundamental understanding, especially when it comes to mixed convective flow. This talk will give an overview of the single-phase research conducted during the past decade at the University of Pretoria, focussing on the laminar, transitional and turbulent flow regimes.
2023-01-20 (Friday)
room 1.40, Pasteura 5 at 09:30
K. Wach, J. Jakubowska, Z. Mizgalewicz, S. Bocian, D. de Macedo (FUW)Student Talks
On Friday 20 January 2023 at 9:30 AM at the UW Faculty of Physics (Pasteura 5, Warsaw; room 1.40) we are hosting short student presentations by:
Neuroinformatics block:
I. How the action potential is generated by Katarzyna Wach
II. Neurotransmitters in the micro- and macroscopic perspective by Julia Jakubowska
III. EEG and rythmic activity of the brain by Zofia Mizgalewicz
IV. Time-Frequency Domain in the Time Series analysis by Szymon Bocian
and one separate student talk:
Modelling an Ionic Liquid by Diogo de Macedo
We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).
Neuroinformatics block:
I. How the action potential is generated by Katarzyna Wach
II. Neurotransmitters in the micro- and macroscopic perspective by Julia Jakubowska
III. EEG and rythmic activity of the brain by Zofia Mizgalewicz
IV. Time-Frequency Domain in the Time Series analysis by Szymon Bocian
and one separate student talk:
Modelling an Ionic Liquid by Diogo de Macedo
We warmly welcome everyone to attend the talk and the Soft Matter Coffee Break after the seminar, held in room 2.63 (2nd floor).
2023-01-13 (Friday)
room 1.40, Pasteura 5 at 09:30
Jeffrey Everts (IFT UW)Charged complex liquids: the Brazil nut effect and Archimedes’ screws
Complex liquids occur in various problems in soft condensed matter, such as colloidal suspensions, liquid crystals, and the cytoplasm of a living cell. In these systems, ions are often present, and they usually play an important role by screening electrostatic interactions or expressing a biological function. In this talk, I will highlight two recent cases where ions in complex liquids lead to unusual phenomena. First, I will show how electrostatics can lead to unusual density sorting in binary mixtures of charged colloids, where heavier particles float on top of the lighter particles. Unlike the granular or active analogue of this system, this colloidal Brazil-nut effect is purely driven by Brownian motion and electrostatics [1]. In the second part of my talk, I will discuss the role of ions in nematic liquid crystals. In our work, we found that ions in liquid crystals can lead to charge separation in the bulk around topological defects [2], surface charge manipulation [3], and anisotropic screening [4]. I will highlight our first efforts to extend such notions to the dynamical case by deriving the Onsager reciprocal coupling between ionic currents and nematic texture [5]. The dynamics are similar to how an Archimedes’ screw works: winding of nematic texture can generate an ionic current, and conversely, ions can push nematic texture, similar to spin pumping and spin torque in spintronics, respectively. Our results suggest that electric currents can facilitate topological defect transport and that defects can carry an inductance, paving the way for using defects as electric circuitry.
[1] M. N. van der Linden, J. C. Everts, R. van Roij, and A. van Blaaderen, submitted, arXiv:2208.11102 (2022).
[2] J. C. Everts and M. Ravnik, Phys. Rev. X 11, 011054 (2021).
[3] M. Ravnik and J. C. Everts, Phys. Rev. Lett. 125, 037801 (2020).
[4] J. C. Everts, B. Senyuk, H. Mundoor, M. Ravnik and I. I. Smalyukh, Sci. Adv. 7, eabd0662 (2021).
[5] C. Dao, J. C. Everts, M. Ravnik, and Y. Tserkovnyak, submitted, arXiv:2210.17116 (2022).
[1] M. N. van der Linden, J. C. Everts, R. van Roij, and A. van Blaaderen, submitted, arXiv:2208.11102 (2022).
[2] J. C. Everts and M. Ravnik, Phys. Rev. X 11, 011054 (2021).
[3] M. Ravnik and J. C. Everts, Phys. Rev. Lett. 125, 037801 (2020).
[4] J. C. Everts, B. Senyuk, H. Mundoor, M. Ravnik and I. I. Smalyukh, Sci. Adv. 7, eabd0662 (2021).
[5] C. Dao, J. C. Everts, M. Ravnik, and Y. Tserkovnyak, submitted, arXiv:2210.17116 (2022).
2022-12-16 (Friday)
room 1.40, Pasteura 5 at 09:30
Tomasz Kamiński (University of Warsaw, Faculty of Biology; University of Cambridge, Department of Biochemistry)Droplet microfluidics for ultrahigh-throughput screening and single cell assays
Droplet microfluidics is a relatively new and rapidly evolving field of science focused on studying the hydrodynamics and properties of biphasic flows at the microscale, and on the development of systems for practical applications in chemistry and biology. The ability to generate, manipulate and monitor millions of monodisperse picoliter water-in-oil droplets provide a new format in which experiments can be conducted faster and with minimal reagent consumption. The seminar will cover our recent work focused on the discovery and improvement of plastic-degrading enzymes and functional selection of rare strains of bacteria using passive droplet sorting by interfacial tension. I will also present novel multi-step microfluidic technologies for genomic analysis of single mammalian cells encapsulated in droplets.
2022-12-09 (Friday)
room 1.40, Pasteura 5 at 09:30
Łukasz Klotz (Warsaw University of Technology & Institute of Science and Technology Austria)Phase Transition to Turbulence in Spatially Extended Shear Flows
Directed percolation (DP) has recently emerged as a possible solution to the century old puzzle surrounding the transition to turbulence. Multiple model studies reported DP exponents, however, experimental evidence is limited since the largest possible observation times are orders of magnitude shorter than the flows’ characteristic timescales. An exception is cylindrical Couette flow where the limit is not temporal, but rather the realizable system size. We present experiments in a Couette setup of unprecedented azimuthal and axial aspect ratios. Approaching the critical point to within less than 0.1% we determine five critical exponents, all of which are in excellent agreement with the 2+ 1 D DP universality class. The complex dynamics encountered at the onset of turbulence can hence be fully rationalized within the framework of statistical mechanics.
2022-12-02 (Friday)
room 1.40, Pasteura 5 at 09:30
Wilhelm Johann van den Bergh (University of Pretoria)Experimental boiling: Close encounters of a doctoral kind
Empirical correlations have been used to predict heat transfer coefficients for decades, with varying degrees of accuracy. With the urgency of developing more efficient concentrated solar power systems, the need is real to improve these correlations to account for the fickle nature of the sun. This is a cautionary tale of attempting to model this transient nature experimentally and the pitfalls encountered along the way.