Заседание на КОЛОКВИУМ "акад. Р. КАИШЕВ" на ИФХ-БАН |
| 05.02.2025 |
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Уважаеми колеги, |
| Във връзка с гостуването на проф. Panos Theodorakis от Institute of Physics, Polish Academy of Sciences, Soft Matter and Fluids Physics Group, по програмата CEEPUS (Central European Exchange Program for University Studies), на 14.10.2025 (вторник) и на 16.10.2025 (четвъртък) в зала 225, етаж 2, блок 11, Институт по физикохимия, Кампус Гео Милев – БАН ще бъдат изнесени следните лекции: |
1. На 14.10.2025 (вторник):
Lecture I - 10:00 ч: (2x45 min) Molecular dynamics simulation of directed fluid flow on gradient substrates
Lecture II - 14:00 ч: (2x45 min) Many-body dissipative particle dynamics simulation of droplet topological changes and MDPD-MARTINI force-field.
2. На 16.10.2025 (четвъртък):
Lecture III - 10:00 ч: (2x45 min) Molecular dynamics simulation of droplet topological changes and superspreading.
Lecture 1 (Oct 14, Tuesday morning, 2x45 min)
Title: Molecular dynamics simulation of directed fluid flow on gradient substrates
Directed fluid flow is much relevant for various applications, such as microfluidics. In this regard, causing and sustaining the fluid motion without requiring supply from an external energy source is highly desirable. In these lectures, we will discuss advancements in this area by molecular dynamics (MD) simulations of physics-based coarse-grained force-fields. Specifically, three novel designs of brush and gel substrates suitable for durotaxis and antiduotaxis motion due to stiffness gradients will be discussed and the mechanisms of motion will be explained along other properties. In addition, we will present results on the rugotaxis motion of droplets on wavy substrates with gradient on the wavelength characterising its wavy structure and discuss pinning effects relevant in these systems.
Literature:
1) R. Kajouri, P. E. Theodorakis, J. Židek, A. Milchev, “Antidurotaxis droplet motion onto gradient brush substrates”, Langmuir 39, 15285 (2023)
2) R. Kajouri, P. E. Theodorakis, A. Milchev, “Durotaxis and antidurotaxis droplet motion onto gradient gel-substrates”, Langmuir 40, 17779 (2024)
3) R. Kajouri, P. E. Theodorakis, P. Deuar, R. Bennacer, J. Židek, S. A. Egorov, A. Milchev, “Unidirectional droplet propulsion onto gradient brushes without external energy supply”, Langmuir 39, 2818-2828 (2023)
4) P. E. Theodorakis, S. A. Egorov, A. Milchev, “Rugotaxis: Droplet motion without external energy supply”, EPL 137, 43002 (2022)
5) P. E. Theodorakis, S. Egorov, A. Milchev, “Stiffness-guided motion of a droplet on a solid substrate”, Journal of Chemical Physics 146, 015504 (2017)
6) P. E. Theodorakis, A. Amirfazli, B. Hu, Z. Che, “Droplet control based on pinning and substrate wettability”, Langmuir 37, 4248 – 4255 (2021)
Lecture 2 (Oct 14, Tuesday afternoon, 2x45 min)
Title: Many-body dissipative particle dynamics simulation of droplet topological changes and MDPD-MARTINI force-field
Many-body dissipative particle dynamics (MDPD) is a relatively new method that allows for the investigation of larger systems than molecular dynamics. Among others, the method is particularly suitable for simulating fluids and a range of complex soft matter systems. In this lecture, we present results on topological changes of droplets, in particular, the Rayleigh – Plateau instability. We will also present results on droplets oscillations on solid, vibrating substrates discussing the different behaviour and properties. Finally, I will report on the ongoing development of the MDPD-MARTINI force-field, which is based on the standard MD-MARTINI mapping but provides an order of magnitude speed-up in simulations by taking advantage of the MDPD approach.
Literature:
1) N. Kramarz, L.H. Carnevale, P.E. Theodorakis, “Many-body dissipative particle dynamics simulations of lipid bilayers with the MDPD-MARTINI force-field”, The European Physical Journal Plus 140, 576 (2025)
2) K. L. Ng, L.H. Carnevale, M. Klamka, P. Deuar, T. Bobiński, P. E. Theodorakis, “Oscillations of a water droplet onto a horizontally vibrating substrate”, Physics of Fluids 37, 014121 (2025), doi: 10.1063/5.0250009
3) L. H. Carnevale, P. E. Theodorakis, “Many-body dissipative particle dynamics with the MARTINI ‘’Lego” approach”, The European Physical Journal Plus 139, 539 (2024)
4) L. H. Carnevale, P. Deuar, Z. Che, P. E. Theodorakis, “Surfactant-laden liquid thread breakup driven by thermal fluctuations”, Physics of Fluids 36, 033301 (2024)
5) L. H. Carnevale, P. Deuar, Z. Che, P. E. Theodorakis, “Liquid thread breakup and the formation of satellite droplets”, Physics of Fluids 35, 074108 (2023)
Lecture 3 (Oct 16, Thursday morning, 2x45 min)
Title: Molecular dynamics simulation of droplet topological changes and superspreading
Topological changes of droplets, such as coalescence, impact, and breakup are or relevance for various applications, such as spray cooling. In this lecture, I will report on the colalescence and collision of droplets laden with surfactant, which have been investigated by means of molecular dynamics simulation based on coarse-grained models that take into account the chemical nature of the groups of atoms that the beads represent. Finally, I will also present results regarding droplet superspreading on solid substrates due to superspreader surfactants, whose mechanisms had reamained unexplained for many decades.
Literature:
1) S. Arbabi, P. Deuar, R. Bennacer, Z. Che, P.E. Theodorakis, “Collisiono of surfactant-laden droplets: Insights from molecular dynamics simulation”, Soft Matter 21, 6366 (2025)
2) S. Arbabi, P. Deuar, R. Bennacer, Z. Che, P. E. Theodorakis, “Coalescence of sessile aqueous droplets laden with surfactants”, Physics of Fluids 36, 023340 (2024)
3) S. Arbabi, P. Deuar, M. Denys, R. Bennacer, Z. Che, P. E. Theodorakis, “Molecular dynamics simulation of the coalescence of surfactant-laden droplets”, Soft Matter 19, 8070 (2023)
4) S. Arbabi, P. Deuar, M. Denys, R. Bennacer, Z. Che, P. E. Theodorakis, “Coalescence of surfactant-laden droplets”, Physics of Fluids 35, 063329 (2023)
5) S. Arbabi, P. E. Theodorakis, “Coalescence of sessile polymer droplets: A molecular dynamics study”, Macromolecular Theory and Simulations 32, 2300017 (2023)
6) E. R. Smith, P. E. Theodorakis, R. V. Craster, O. K. Matar, “Moving contact lines: linking molecular dynamics and continuum-scale modelling”, Langmuir 34, 12501 (2018)
7) P. E. Theodorakis, E. A. Müller, R. V. Craster, O. K. Matar, “Modelling the superspreading of surfactant-laden droplets with computer simulation”, Soft Matter 11, 9254 (2015)
8) P. E. Theodorakis, E. A. Müller, R. V. Craster, O. K. Matar, “Superspreading: Mechanisms and molecular design”, Langmuir 31, 2304 (2015)
9) P. E. Theodorakis, E. A. Müller, R. V. Craster, O. K. Matar, “Insights into surfactant-assisted superspreading”, Current Opinion in Colloid & Interface Science 19, 283 (2014)
10) P. E. Theodorakis, E.R. Smith, R.V. Craster, E.A. Müller, O.K. Matar “Molecular dynamics simulation of the superspreading of surfactant-laden droplets. A review”, Fluids 4, 176 (2019)
11) P. E. Theodorakis, E.R. Smith, E.A. Müller, “Spreading of aqueous droplets with common and superspreading surfactants. A molecular dynamics study”, Colloids & Surfaces A: Physicochemical and Engineering Aspects 581, 123810 (2019)
12) E.R. Smith, P. E. Theodorakis, “Multiscale simulation of fluids: Coupling molecular and continuum”, Physical Chemistry Chemical Physics 26, 724 (2024)
