ICSC PAS Articles

Displaying 1 - 5 of 24 records

Dynamic nanostructures at the surface of rising bubbles in amphiphile solutions: Comparison of low-molecular-weight surfactants and proteins
(Elsevier B.V., 2025-03-10) Witkowski, Łukasz; Wiertel-Pochopien, Agata; Kosior, Dominik; Gochev, Georgi G.; Warszynski, Piotr; Fuller, Gerald G.; Zawala, Jan; Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland; Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria; Department of Chemical Engineering, Stanford University, Stanford, USA
The formation, stability, and decay of foams occur under dynamic conditions. Given their inherent complexity, an accurate description of these subprocesses necessitates an analysis of multiple factors, with a particular focus on the formation and structure of the adsorption layer. Single rising bubble techniques facilitate a deeper comprehension of the dynamics of diverse phenomena in foams, as they yield experimental data under dynamic conditions. This review examines the subtle differences in the dynamic adsorption structures of low-molecular-weight surfactants and proteins at the liquid/gas interface. These differences can significantly impact interfacial properties and potentially alter our understanding of the mechanisms behind the formation of the Dynamic Adsorption Layer (DAL). The primary techniques under consideration are local velocity profiles (LVPs) of single rising bubbles and dynamic fluid-film interferometry (DFI) of the thin liquid film formed at the collision of a bubble with a free liquid surface. We provide a summary of recent findings on the topic. Due to the limited availability of comprehensive datasets on proteins, our discussion is partially supplemented by newly obtained unpublished data. We highlight key differences in the behavior of bubbles in low-molecular-weight surfactant solutions versus protein solutions that have previously been overlooked in the literature. We explore their potential origins in the context of DAL dynamics and architecture.
Effect of Synthetic Polypeptide–Bio-Surfactant Composition on the Formation and Stability of Foams
(MDPI, 2024-10-30) Kosior, Dominik; Wiertel-Pochopien, Agata; Morga, Maria; Witkowski, Łukasz; Zawala, Jan; Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
Abstract: In recent decades, numerous studies have focused on finding environmentally friendly substitutes for commonly used petrochemical-based compounds. This paper explores the potential use of poly-L-lysine/rhamnolipids and poly-L-glutamic acid/ethyl lauroyl arginate mixtures, for foam formation and stabilization. Two complementary methods were employed to investigate the synergistic and antagonistic effects of these mixed polyelectrolyte/surfactant systems: (1) the thinning and rupture of thin foam films formed under dynamic conditions were monitored using a dynamic fluid-film interferometer (DFI), and (2) foamability tests were conducted using a standard dynamic foam analyzer (DFA). The results demonstrated that adding polyelectrolyte to an oppositely charged surfactant primarily induces a synergistic effect, enhancing foaming properties and extending foam lifetime. Furthermore, interferometric methods confirmed improved stability and slower drainage of thin foam films in systems containing synthetic polypeptides.
Exploring proteins at soft interfaces and in thin liquid films – From classical methods to advanced applications of reflectometry
(Elsevier B.V., 2024-05-23) Gochev, Georgi G.; Campbell, Richard A.; Schneck, Emanuel; Zawala, Jan; Warszynski, Piotr; Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland; Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria; Division of Pharmacy and Optometry, University of Manchester, Manchester, UK; Physics Department, Technical University Darmstadt, Darmstadt, Germany
The history of the topic of proteins at soft interfaces dates back to the 19th century, and until the present day, it has continuously attracted great scientific interest. A multitude of experimental methods and theoretical approaches have been developed to serve the research progress in this large domain of colloid and interface science, including the area of soft colloids such as foams and emulsions. From classical methods like surface tension adsorption isotherms, surface pressure-area measurements for spread layers, and surface rheology probing the dynamics of adsorption, nowadays, advanced surface-sensitive techniques based on spectroscopy, microscopy, and the reflection of light, X-rays and neutrons at liquid/fluid interfaces offers important complementary sources of information. Apart from the fundamental characteristics of protein adsorption layers, i.e., surface tension and surface excess, the nanoscale structure of such layers and the interfacial protein conformations and morphologies are of pivotal importance for extending the depth of understanding on the topic. In this review article, we provide an extensive overview of the application of three methods, namely, ellipsometry, X-ray reflectometry and neutron reflectometry, for adsorption and structural studies on proteins at water/air and water/oil interfaces. The main attention is placed on the development of experimental approaches and on a discussion of the relevant achievements in terms of notable experimental results. We have attempted to cover the whole history of protein studies with these techniques, and thus, we believe the review should serve as a valuable reference to fuel ideas for a wide spectrum of researchers in different scientific fields where proteins at soft interface may be of relevance.
Macroion adsorption− electrokinetic and optical methods
(2017) Michna, Aneta; Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences
Recent studies on macroion adsorption at solid/ liquid interfaces evaluated by electrokinetic and optical methods are reviewed. In the first section the description of the electrokinetic phenomena at solid surface is briefly outlined. Various methods for determining both the static and the dynamic properties of electrical double layer, such as: the appropriate location of the slip plane, were presented. The theoretical approaches are discussed concerning quantitative interpretation of the streaming potential/ current measurements of homogeneous macroscopic interfaces, both bare and formed by microsphere adsorption. Experimental results are presented, involving the electrokinetic characteristics of bare surfaces, such as mica, silicon, glass etc. obtained from various types of electrokinetic cells. The effect of surface conductivity on the zeta potential was underlined. In the next section, various theoretical approaches, proposed to determine the distribution of electrostatic potential and flow distribution within macroion layers, were disscused. Accordingly, the influence of the uniform as well as non−uniform distribution of charges within macroion layer, the dissociation degree, and the surface conductance on electrokinetic parameters were discussed. The last section was devoted to the discussion of experimental data obtained by the streaming potential/ current measurements and optical methods, such as reflectometry, ellipsometry, surface plasmon resonance (SPR), colloid enhancement, and fluorescence technique, for mono− and multilayers of macroions. Results of polcations (PEI, PAMAM dendrimers, PAH, PDADMAC) and polyanions (PAA, PSS) adsorption on mica, silicon, gold, and PTFE are quantitatively interpreted in terms of theoretical approaches postulating the three dimensional charge distribution or random sequential adsorption model (RSA). Macroion bilayer formation, experimentally examined by streaming current measurements, and theoretically interpreted in terms of the comprehensive formalism was also reviewed. The utility of the electrokinetic measurements, combined with optical methods, for a precise, in situ characteristics of macroion mono− and multilayer formation at soid/ liquid interfaces is pointed out.
Coalescence of surface bubbles: The crucial role of motion-induced dynamic adsorption layer
(Elsevier, 2023-06-01) Zawała, Jan; Miguet, Jonas; Rastogi, Preetika; Atasi, Omer; Borkowski, Mariusz; Scheid, Benoit; Fuller, Gerald G.; Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Krakow, Poland; Department of Chemical Engineering, Stanford University, Stanford, USA; Department of Chemical Engineering, Indian Institute of Technology, Chennai, Tamil Nadu, India; TIPs, Fluid Physics Unit, Université Libre de Bruxelles, Bruxelles, Belgium
The formation of motion-induced dynamic adsorption layers of surfactants at the surface of rising bubbles is a widely accepted phenomenon. Although their existence and formation kinetics have been theoretically postulated and confirmed in many experimental reports, the investigations primarily remain qualitative in nature. In this paper we present results that, to the best of our knowledge, provide a first quantitative proof of the influence of the dynamic adsorption layer on drainage dynamics of a single foam film formed under dynamic conditions. This is achieved by measuring the drainage dynamics of single foam films, formed by air bubbles of millimetric size colliding against the interface between n-octanol solutions and air. This was repeated for a total of five different surfactant concentrations and two different liquid column heights. All three steps preceding foam film rupture, namely the rising, bouncing and drainage steps, were sequentially examined. In particular, the morphology of the single film formed during the drainage step was analyzed considering the rising and bouncing history of the bubble. It was found that, depending on the motion-induced state of adsorption layer at the bubble surface during the rising and the bouncing steps, single foam film drainage dynamics can be spectacularly different. Using Direct Numerical Simulations (DNS), it was revealed that surfactant redistribution can occur at the bubble surface as a result of the bouncing dynamics (approach-bounce cycles), strongly affecting the interfacial mobility, and leading to slower rates of foam film drainage. Since the bouncing amplitude directly depends on the rising velocity, which correlates in turn with the adsorption layer of surfactants at the bubble surface during the rising step, it is demonstrated that the lifetime of surface bubbles should intimately be related to the history of their formation.

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