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Piotr Warszyński - One of the best experts on this subject based on the ideXlab platform.

  • Interfacial and structural characteristics of polyelectrolyte multilayers used as cushions for supported lipid bilayers
    Soft matter, 2017
    Co-Authors: Magdalena Wlodek, Marta Kolasinska-sojka, Monika Wasilewska, Oier Bikondoa, Wuge H. Briscoe, Piotr Warszyński
    Abstract:

    The surface properties of polyelectrolyte multilayers (PEMs) obtained via sequential adsorption of oppositely charged polyions from their solutions and used as cushions for supported lipid bilayers were investigated. Five types of polyelectrolytes were used: cationic polyethyleneimine (PEI), poly(diallyldimethylammonium)chloride (PDADMAC), and poly-L-lysine hydrobromide (PLL); and anionic Polysodium 4-Styrenesulfonate (PSS) and poly-L-glutamic acid sodium (PGA). The wettability and surface free energy of the PEMs were determined by contact angle measurements using sessile drop analysis. Electrokinetic characterisation of the studied films was performed by streaming potential measurements of selected multilayers and the structure of the polyelectrolyte multilayer was characterized by synchrotron X-ray reflectometry. The examined physicochemical properties of the PEMs were correlated with the kinetics of the formation of supported lipid bilayers atop the PEM cushion.

  • Co-adsorption of polyanions and esterquat surfactants; effect on formation and stability of micellar core nanocapsules
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017
    Co-Authors: Krzysztof Szczepanowicz, Grażyna Para, Kazimiera A. Wilk, Piotr Warszyński
    Abstract:

    Abstract We investigated the co-adsorption at water/air interface of soft cationic surfactants of the esterquat-type, fatty acid quaternary ammonium esters with hydrocarbon chain containing eleven carbons and the amino acid betaine esters with twelve carbons in the chain with polyanions: Polysodium 4–styrenesulfonate (PSS), poly- l -glutamic acid sodium salt (PGA), alginic acid sodium salt (ALG) and λ-carrageenan (CAR). The effect of surfactants basic hydrolysis on formation of surfactant/polymer complexes in bulk and at interface was taken into account. We found that the surface charge of the water/air interface originating from the adsorption of fatty acid quaternary ammonium esters decreased as the result of hydrolysis that led to lower co-adsorption of polyanions than in the case of amino acid betaine esters. The optimal conditions for formation of surfactant micelles/polyelectrolyte aggregates were established. These negatively charged aggregates were further used as nanocores for encapsulation by the layer-by-layer (LbL) adsorption of synthetic and natural polyelectrolytes. The average size of nanocapsules was in range 100–200 nm. We observed that stability of micellar cores were dependent on the rate of esterquat hydrolysis, ones formed with fast hydrolysable surfactant were stable under acidic but unstable under basic conditions.

  • The effect of anchoring PEI layer on the build-up of polyelectrolyte multilayer films at homogeneous and heterogeneous surfaces
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009
    Co-Authors: Anna Trybala, Lilianna Szyk-warszyńska, Piotr Warszyński
    Abstract:

    Abstract Expanding area of applications of polyelectrolyte multilayers requires the extensive studies of the processes of their adsorption at real surfaces, which are often very rough and chemically heterogeneous. We investigated adsorption of polyelectrolytes at surfaces of polished and unpolished surgical stainless steel (used in medicine as a material for stents), at titanium plates (material for implants) and silicon plates (material for microelectronics). Films (PAH*/PSS) n , PEI(PSS/PAH*) n with a number of layers varied between 1 and 11 were formed on silicon wafers, stainless steel, titanium plates (PAH * – poly(fluorescein isothiocyanate allylamine hydrochloride), PSS – Polysodium 4-Styrenesulfonate, PEI – polyethyleneimine). The effect of the first polyethyleneimine layer and surface roughness on the formation of polyelectrolyte multilayer films on these surfaces was investigated. The amount of polymer adsorbed in the multilayer was determined by fluorescent microscopy. Film thickness formed on polished Si/SiO 2 surface was measured by ellipsometry. Results obtained indicate that PEI anchoring layer has an influence on the PE film properties depending on the conditions of film formation and on the roughness of the supporting surface. At surfaces with higher roughness stronger effect of PEI is observed.

  • Characteristics of polyelectrolyte multilayers: The effect of polyion charge on thickness and wetting properties
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2008
    Co-Authors: Magdalena Elzbieciak, Marta Kolasińska, Piotr Warszyński
    Abstract:

    Abstract Polyelectrolyte (PE) multilayer films are surface structures obtained by sequential adsorption of oppositely charged polymers. In the present work we focused on the influence of pH of the solutions of strong and weak polyelectrolytes on the thickness and wetting of multilayers formed on silicon wafers. Four types of PE were used: polyallamine hydrochloride (PAH), poly(diallyldimethylammonium)chloride (PDADMAC), poly(acrylic acid) (PAA), Polysodium 4-Styrenesulfonate (PSS). Thickness of PE films was measured by ellipsometry and their wetting properties were determined by contact angle measurements. Thicker films were found in conditions when the polyelectrolytes were weakly charged. We observed periodic, layer-to-layer oscillations of contact angle values with the amplitude dependent on type of PE pair and conditions of film formation, however, films with a polycation as the top layer were more hydrophobic.

  • Characterization of polyelectrolyte multilayers on mica and oxidized titanium by streaming potential and wetting angle measurements
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2007
    Co-Authors: Zbigniew Adamczyk, Marta Kolasińska, Maria Zembala, Piotr Warszyński
    Abstract:

    Abstract Multilayer adsorption of polyelectrolytes on mica and electrochemically oxidized titanium was studied by the streaming potential method using a parallel-plate channel arrangement. Streaming potential data were complemented by wetting angle measurements. Two types of polyelectrolytes (PE) were used: polyallylamine hydrochloride (PAH), of a cationic type, and Polysodium 4-Styrenesulfonate (PSS) of an anionic type (both having molecular weight of ∼70,000). Layer by layer adsorption of polyelectrolytes from NaCl and TRIS solutions of various concentrations was studied in situ. It was demonstrated that after completing a bilayer, periodic variations in the apparent zeta potential between positive and negative values appeared for multilayers terminated by PAH and PSS, respectively. This was in accordance with zeta potential of the polymers in the bulk measured by electrophoresis. It also was observed that streaming potential data correlated well with the wetting angle characteristics of dried polyelectrolyte films. Variations in the contact angle between 70° for PAH and 40° for PSS were exactly in phase with the variation in the zeta potential. The stability of polyelectrolyte films against prolong washing (reaching 24 h) was determined using the streaming potential method. It was revealed that both for mica and titanium, the PSS layer was considerably more resistant to washing, compared to the PAH layer. The experimental data obtained were consistent with a model postulating particle-like adsorption of polyelectrolytes.

Marta Kolasińska - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of polyelectrolyte multilayers: The effect of polyion charge on thickness and wetting properties
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2008
    Co-Authors: Magdalena Elzbieciak, Marta Kolasińska, Piotr Warszyński
    Abstract:

    Abstract Polyelectrolyte (PE) multilayer films are surface structures obtained by sequential adsorption of oppositely charged polymers. In the present work we focused on the influence of pH of the solutions of strong and weak polyelectrolytes on the thickness and wetting of multilayers formed on silicon wafers. Four types of PE were used: polyallamine hydrochloride (PAH), poly(diallyldimethylammonium)chloride (PDADMAC), poly(acrylic acid) (PAA), Polysodium 4-Styrenesulfonate (PSS). Thickness of PE films was measured by ellipsometry and their wetting properties were determined by contact angle measurements. Thicker films were found in conditions when the polyelectrolytes were weakly charged. We observed periodic, layer-to-layer oscillations of contact angle values with the amplitude dependent on type of PE pair and conditions of film formation, however, films with a polycation as the top layer were more hydrophobic.

  • Characterization of polyelectrolyte multilayers on mica and oxidized titanium by streaming potential and wetting angle measurements
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2007
    Co-Authors: Zbigniew Adamczyk, Marta Kolasińska, Maria Zembala, Piotr Warszyński
    Abstract:

    Abstract Multilayer adsorption of polyelectrolytes on mica and electrochemically oxidized titanium was studied by the streaming potential method using a parallel-plate channel arrangement. Streaming potential data were complemented by wetting angle measurements. Two types of polyelectrolytes (PE) were used: polyallylamine hydrochloride (PAH), of a cationic type, and Polysodium 4-Styrenesulfonate (PSS) of an anionic type (both having molecular weight of ∼70,000). Layer by layer adsorption of polyelectrolytes from NaCl and TRIS solutions of various concentrations was studied in situ. It was demonstrated that after completing a bilayer, periodic variations in the apparent zeta potential between positive and negative values appeared for multilayers terminated by PAH and PSS, respectively. This was in accordance with zeta potential of the polymers in the bulk measured by electrophoresis. It also was observed that streaming potential data correlated well with the wetting angle characteristics of dried polyelectrolyte films. Variations in the contact angle between 70° for PAH and 40° for PSS were exactly in phase with the variation in the zeta potential. The stability of polyelectrolyte films against prolong washing (reaching 24 h) was determined using the streaming potential method. It was revealed that both for mica and titanium, the PSS layer was considerably more resistant to washing, compared to the PAH layer. The experimental data obtained were consistent with a model postulating particle-like adsorption of polyelectrolytes.

  • Characteristics of polyelectrolyte multilayers: effect of PEI anchoring layer and posttreatment after deposition.
    Journal of colloid and interface science, 2006
    Co-Authors: Marta Kolasińska, Rumen Krastev, Piotr Warszyński
    Abstract:

    The influence of a first (anchoring) layer and film treatment on the structure and properties of polyelectrolyte multilayer (PEM) films obtained from polyallylamine hydrochloride (PAH) and Polysodium 4-Styrenesulfonate (PSS) was studied. Branched polyethyleneimine (PEI) was used as an anchoring layer. The film thickness was measured by ellipsometry. Complementary X-ray reflectometry and AFM experiments were performed to study the change in the interfacial roughness. We found that the thickness of the PEM films increased linearly with the number of layers and depended on the presence of an anchoring PEI layer. Thicker films were obtained for multilayers having PEI as the first layer comparing to films having the same number of layers but consisting of PAH/PSS only. We investigated the wettability of PEM surfaces using direct image analysis of the shape of sessile water drops. Periodic oscillations in contact angle were observed. PAH-terminated films were more hydrophobic than films with PSS as the outermost layer. The effect of long time conditioning of PEM films in solutions of various pH's or salt (NaCl) concentrations was also examined. Salt or base solutions induced modification in wetting properties of the polyelectrolyte multilayers but had a negligible effect on the film thickness.

  • The effect of nature of polyions and treatment after deposition on wetting characteristics of polyelectrolyte multilayers
    Applied Surface Science, 2005
    Co-Authors: Marta Kolasińska, Piotr Warszyński
    Abstract:

    Abstract The sequential adsorption of oppositely charged polyelectrolytes (PE) occurs to be a powerful tool for obtaining various materials of precisely defined properties. The interfacial features of PE multilayer films are governed by the choice of polycation/polyanion pairs and the conditions of film formation. Additionally, the long time exposure to the conditions different than that encountered during formation usually affects polyelectrolyte multilayer structure. The wettability of heterogeneous surfaces produced by ‘layer-by-layer’ (LbL) adsorption of polyelectrolytes was investigated in this work. We focused on the influence of film treatment after deposition on wetting properties of obtained multilayers. The effect of the nature of the first layer was also studied. Apart from simple arrangements: (polyallylamine hydrochloride)/(Polysodium 4-Styrenesulfonate) (PAH/PSS) and (poly- l -lysine hydrobromide)/(poly- l -glutamic acid sodium salt) (PLL/PGA) more complicated structures were considered having as a first layer two types of polyethylene imines (PEI) of different molecular weight. Wetting properties of such polyelectrolyte films were determined experimentally by contact angle measurements using technique of direct image analysis of the shape of sessile drop.

  • The effect of support material and conditioning on wettability of PAH/PSS multilayer films.
    Bioelectrochemistry (Amsterdam Netherlands), 2005
    Co-Authors: Marta Kolasińska, Piotr Warszyński
    Abstract:

    An efficient method for characterizing wetting properties of heterogeneous surfaces produced by sequential adsorption of polyelectrolytes was developed. Three types of polyelectrolytes were used: polyallylamine hydrochloride (PAH), polyethyleneimine (PEI), both of a cationic type, and Polysodium 4-Styrenesulfonate (PSS), of an anionic type. Multilayer films were prepared by 'layer-by-layer' (LbL) deposition technique. Natural ruby mica, glass, titanium foil and silicon wafers were used as the support material for PE films. Wetting of polyelectrolyte films was determined experimentally by contact angle measurements, using technique of direct image analysis of shape of sessile drops. Periodic oscillations in contact angle values were observed for multilayers terminated by polycation and polyanion, respectively, and the variations in contact angle values strongly depended on the conditions of adsorption and multilayer treatment after deposition. Therefore, the influence of ionic strength of polyelectrolyte solution used for deposition on wetting of multilayer films was considered and also the effect of conditioning in different environments was investigated. It is usually assumed that film properties and stability strongly depend on the first layer which is used to anchor a multilayer at the surface of support material. To investigate influence of the first layer, PAH/PSS films were compared with more complex ones having PEI as the first layer with a sequence of PSS/PAH deposited on top of it.

Cátia Magro - One of the best experts on this subject based on the ideXlab platform.

  • Polyelectrolyte Based Sensors as Key to Achieve Quantitative Electronic Tongues: Detection of Triclosan on Aqueous Environmental Matrices
    Nanomaterials (Basel Switzerland), 2020
    Co-Authors: Cátia Magro, Paulo M. Zagalo, João Pereira-da-silva, Eduardo P. Mateus, Alexandra B. Ribeiro, Paulo A. Ribeiro, M. Manuela M. Raposo
    Abstract:

    Triclosan (TCS) is a bacteriostatic used in household items that promotes antimicrobial resistance and endocrine disruption effects both to humans and biota, raising health concerns. In this sense, new devices for its continuous monitoring in complex matrices are needed. In this work, sensors, based on polyelectrolyte layer-by-layer (LbL) films prepared onto gold interdigitated electrodes (IDE), were studied. An electronic tongue array, composed of (polyethyleneimine (PEI)/Polysodium 4-Styrenesulfonate (PSS))5 and (poly(allylamine hydrochloride/graphene oxide)5 LbL films together with gold IDE without coating were used to detect TCS concentrations (10-15-10-5 M). Electrical impedance spectroscopy was used as means of transduction and the obtained data was analyzed by principal component analysis (PCA). The electronic tongue was tested in deionized water, mineral water and wastewater matrices showing its ability to (1) distinguish between TCS doped and non-doped solutions and (2) sort out the TCS range of concentrations. Regarding film stability, strong polyelectrolytes, as (PEI/PSS)n, presented more firmness and no significant desorption when immersed in wastewater. Finally, the PCA data of gold IDE and (PEI/PSS)5 sensors, for the mineral water and wastewater matrices, respectively, showed the ability to distinguish both matrices. A sensitivity value of 0.19 ± 0.02 per decade to TCS concentration and a resolution of 0.13 pM were found through the PCA second principal component.

  • Triclosan Detection in Aqueous Environmental Matrices by Thin-Films Sensors
    Proceedings, 2019
    Co-Authors: Cátia Magro, Paulo M. Zagalo, João Pereira-da-silva, Eduardo P. Mateus, Alexandra B. Ribeiro, Paulo A. Ribeiro, Maria Raposo
    Abstract:

    Triclosan (TCS), a bacteriostatic detected in water bodies, have inauspicious effects in human and biota. Consequently, there is a critical need of monitoring these type of compounds in aqueous matrices. In this sense, sensors, based on polyethyleneimine and Polysodium 4-Styrenesulfonate layer-by-layer thin-films adsorbed on supports with gold interdigitated electrodes deposited, were developed. The aim was analyze the sensitivity of discrimination of TCS (10−15 M to 10−5 M) in deionized water, Luso® and in an effluent, by measuring the impedance spectra. LbL films can distinguish TCS concentrations in EF, while in LW was achieved an acceptable sensibility when interdigitated electrodes without films were used.

Maria Raposo - One of the best experts on this subject based on the ideXlab platform.

  • Triclosan Detection in Aqueous Environmental Matrices by Thin-Films Sensors
    Proceedings, 2019
    Co-Authors: Cátia Magro, Paulo M. Zagalo, João Pereira-da-silva, Eduardo P. Mateus, Alexandra B. Ribeiro, Paulo A. Ribeiro, Maria Raposo
    Abstract:

    Triclosan (TCS), a bacteriostatic detected in water bodies, have inauspicious effects in human and biota. Consequently, there is a critical need of monitoring these type of compounds in aqueous matrices. In this sense, sensors, based on polyethyleneimine and Polysodium 4-Styrenesulfonate layer-by-layer thin-films adsorbed on supports with gold interdigitated electrodes deposited, were developed. The aim was analyze the sensitivity of discrimination of TCS (10−15 M to 10−5 M) in deionized water, Luso® and in an effluent, by measuring the impedance spectra. LbL films can distinguish TCS concentrations in EF, while in LW was achieved an acceptable sensibility when interdigitated electrodes without films were used.

Huijun Jiang - One of the best experts on this subject based on the ideXlab platform.

  • Layer-by-layer assembled multilayer films of reduced graphene oxide/gold nanoparticles for the electrochemical detection of dopamine
    Journal of Electroanalytical Chemistry, 2012
    Co-Authors: Shi Liu, Jun Yan, Dandan Zhong, Jiaxing Chen, Liying Shi, Xuemin Zhou, Huijun Jiang
    Abstract:

    Abstract Graphene/gold nanoparticle multilayer films composed of Polysodium 4-Styrenesulfonate (PSS) functionalized reduced graphene oxide (RGO) and polyamidoamine (PAMAM) dendrimer stabilized gold nanoparticles (AuNPs) were built up using the electrostatic layer-by-layer (LBL) self-assembly technique on a glassy carbon electrode (GCE) modified with a first layer of poly(diallyldimethylammonium chloride) (PDDA). The film assembly, the electrochemical property as well as the electrocatalytic activity toward the oxidation of dopamine were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Electrochemical studies exhibit that the LBL assembled RGO/AuNPs films possess an excellent sensing performance for the detection of dopamine with a linear range from 1 μM to 60 μM and a limit of detection (LOD) as low as 0.02 μM based on S / N  = 3. In addition, this electrochemical sensor was applied to the simultaneous detection of dopamine and uric acid by using DPV with high sensitivity and selectivity. The good analytical performance and long-term stability of the proposed sensor can be attributed to the combination of the reduced graphene oxide and gold nanoparticles in the LBL assembly films and the synergistic effect on the electrochemical oxidation of dopamine.