百欧林简报-表界面科学最新文献- KSV NIMA -2019年第13期

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1.Name：Linear, self-assembled patterns appearing spontaneously as a result of DNA-CTMA lipoplex Langmuir-Blodgett deposition on a solid surface

Authors：Jacek Nizioł, Katarzyna Makyła-Juzak, Aleksandra Radko, Robert Ekiert, Joanna Zemła, Natalia Górska, Anna Chachaj-Brekiesz, Monika Marzec, Hubert Harańczyk ａnd Patrycja Dynarowicz-Latka

Journal：Polymer

DOI: 10.1016/j.polymer.2019.121643

Abstract：Recently, solid forms of deoxyrybonucleic acid (DNA) ａnd its lipoplex with hexadecyltrimethylammonium chloride (CTMA) have been studied with great interest, because of potential applications outside life sciences. In the present work we report on spontaneous formation of characteristic self-assembled linear patterns formed with DNA-CTMA on solid support. For this purpose a single-step technique based on Langmuir-Blodgett scheme has been successfully implemented. DNA-CTMA lipoplex is found to be capable of forming insoluble films at the air/water interface. The lipoplex subjected to compression on the free water surface ａnd then transferred onto mica substrate, usually disintegrates into isolated islands. However, if a certain combination of experimental parameters is applied, the DNA-CTMA monolayer splits into elongated parallel structures.

Link：https://www.sciencedirect.com/science/article/pii/S0032386119306275

2.Name：Characteristics of Polypeptide/Phospholipid Monolayers on Water ａnd the Plasma‐Activated Polyetheretherketone Support

Authors：Kacper Przykaza, Klaudia Woźniak, Małgorzata Jurak ａnd Agnieszka Ewa Wiącek

Journal：Journal of Surfactants ａnd Detergents

DOI: 10.1002/jsde.12323

Abstract：Polyetheretherketone (PEEK) is a highly biocompatible polymer widely used in medicine as an implant production material. In this article, the PEEK surface was characterized in terms of its wettabillity properties after the physicochemical modifications by treatment with the low‐temperature air plasma ａnd covering with the Langmuir–Blodgett (LB) monolayers of polypeptide (cyclosporine A, CsA) and/or phospholipid (1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine, DPPC). The LB deposition was preceded by the analysis of miscibility ａnd morphology of monolayers at the air/water interface by means of the Langmuir technique ａnd Brewster angle microscopy (BAM). Then, wettability of the polymer‐supported films was evaluated by the contact angle measurements of three probe liquids of different characters (two polar—water ａnd formamide, one apolar—diiodomethane). The measured contact angles allowed for determination of the surface free energy ａnd its components based on the Lifshitz‐van der Waals/acid–base (LWAB) approach. Some relations between the kind ａnd magnitude of interactions within the model membranes on the water subphase ａnd those of the PEEK‐supported membranes with the liquids were found out. The results allowed obtaining the interesting models of biological coatings with potential applications.

Link：https://aocs.onlinelibrary.wiley.com/doi/full/10.1002/jsde.12323

3.Name：Stimuli-responsive behavior of PNiPAm microgels under interfacial confinement

Authors：Johannes Harrer, Marcel Rey, Simone Ciarella, Hartmut Loewen, Liesbeth m. c. Janssen ａnd Nicolas Vogel

Journal：Langmuir

DOI: 10.1021/acs.langmuir.9b01208

Abstract：The volume phase transition of microgels is one of the most paradigmatic examples of stimuli-responsiveness, enabling a collapse from a highly swollen microgel state into a densely coiled state by an external stimulus. Although well characterized in bulk, it remains unclear how the phase transition is affected by the presence of a confining interface. Here, we demonstrate that the temperature-induced volume phase transition of poly(N-isopropylacrylamide) microgels, conventionally considered an intrinsic molecular property of the polymer, is in fact largely suppressed when the microgel is adsorbed to an air/liquid interface. Our results, supported by molecular dynamics simulations, reveal that dangling polymer chains of microgel particles, spread at the interface under the influence of surface tension, do not undergo any volume phase transition, demonstrating that the balance in free energy responsible for the volume phase transition is fundamentally altered by interfacial confinement. These results imply that important technological properties of such systems, including the temperature-induced destabilization of emulsions, do not occur via a decrease in surface coverage of the microgels but are dominated instead by dangling polymer chains extending into the surrounding water phase.

Link：https://pubs.acs.org/doi/abs/10.1021/acs.langmuir.9b01208

4.Name：Interactions of Na⁺ Cations with a Highly Charged Fatty Acid Langmuir Monolayer: Molecular Description of the Phase Transition

Authors：Adrien Sthoer ａnd Eric Tyrode

Journal：Polymer

DOI: 10.26434/chemrxiv.8796650

Abstract：Vibrational sum frequency spectroscopy has been used to study the molecular properties upon compression of a highly charged arachidic acid Langmuir monolayer, which displays a first order phase transition plateau in the surface pressure - molecular area (-A) isotherm. By targeting vibrational modes from the carboxylic acid headgroup, alkyl chain, ａnd interfacial water molecules, information regarding the surface charge, surface potential, type of ion pair formed, ａnd conformational order of the monolayer could be extracted. The monolayer in the liquid expanded phase is found to be fully charged until reaching the 2D-phase transition plateau, where partial reprotonation, as well as the formation of COO⎺ Na+ contact-ion pairs, start to take place. In the condensed phase after the transition, three headgroup species, mainly hydrated COO⎺, COOH, ａnd COO⎺ Na+ contact-ion pairs could be identified ａnd their proportions quantified. Comparison with theoretical models shows that despite the low ionic strengths used (i.e. 10 mM), the predictions from the Gouy Chapman model are only adequate for the lowest surface densities, when the surface charge does not exceed -0.1 C/m2. In contrast, a modified Poisson-Boltzmann (MPB) model that accounts for the steric effects associated with the finite ion-size, captures many of the experimental observables, including the partial reprotonation, ａnd surface potential changes upon compression. The agreement highlights the importance of hydronium ion – carboxylate interactions, as well as the layer of sodium ions packed at the steric limit, for explaining the phase transition behavior. The MPB model, however, does not explicitly consider the formation of contact ion pairs with the sodium counterion. The experimental results provide a quantitative molecular insight that could be used to test potential extensions to the theory.

Link：https://europepmc.org/abstract/ppr/ppr85006

5.Name：Features of the Formation ａnd Structure of Barium Titanate Langmuir Films

Authors：A. P. Kuzmenko, I. V. Chukhaeva ａnd P. V. Abakumov

Journal：Technical Physics

DOI: 10.1134/S1063784219080097

Abstract：Ferroelectric films of stabilized barium titanate nanoparticles have been obtained from the colloidal system of a sodium oleate aqueous solution by the Langmuir–Blodgett method at the KSV NIMA 2002 facility, coagulants with the most characteristic hydrodynamic diameter of ∼200 nm have been found, ａnd a physical model of their formation from barium titanate nanoparticles in this colloid system has been proposed. Homogeneous ferroelectric films with barium titanate particles ∼20 nm in size ａnd a band gap of 3.6 eV have been deposited. The topological ａnd structural features ａnd distribution of chemical elements in the obtained films on different substrates have been studied by the methods of scanning probe ａnd electron microscopy, vibrational ａnd X-ray photoelectron spectroscopy, as well as X-ray diffractometry.

Link：https://link.springer.com/article/10.1134/S1063784219080097

6.Name：Langmuir-Blodgett films of membrane lipid in the presence of hybrid silsesquioxane, a promising component of biomaterials

Authors：Marta Skrzypiec, Marek Weiss, Katarzyna Dopierała ａnd Krystyna Prochaska

Journal：Materials Science ａnd Engineering: C

DOI: 10.1016/j.msec.2019.110090

Abstract：Functionalized polyhedral oligomeric silsesquioxanes (POSS) derivatives have great potential in biomedical applications such as tissue engineering, drug delivery, biosensors, dental composites ａnd biomedical devices. Having the above in mind, in this paper, the study of the surface characteristics of binary Langmuir-Blodgett films consisting of an open cage silsesquioxane POSS-poly (ethylene glycol) (POSS-PEG) ａnd 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), as a representative of phospholipid was conducted based on contact angle measurements of three liquids. The measured values of the contact angle (with water, formamide ａnd diiodomethane as the wetting liquids) allowed to calculate surface free energy of the films from van Oss et al. approach. The film structure of the deposited layers was evaluated using an atomic force microscope. Analysis of the obtained results led to the conclusion, that the pure DMPE molecules create agglomerates onto a solid substrate, whereas the POSS-PEG molecules form a homogenous monolayer. After an addition of POSS-PEG to lipid film, changes in the surface properties are visible. The wettability as well as surface free energy depend on the molar ratio of both components. The AFM images shed more light on the changes of the DMPE monolayer topography caused by the POSS-PEG addition.

Link：https://www.sciencedirect.com/science/article/pii/S092849311931152X