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Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer., This work was supported by the Ministry of Education and Science of the Russian Federation (Project No. 1362), and ACTIMAT project of Etortek program of the Basque Government and UPV-EHU. Support from Spanish MINECO under project MAT2013-48059-C2-1-R is also acknowledged.

A key challenge in the preparation of nanoplatelet-filled polymer composites is the ability to realize the nanometer-level dispersion and the planar orientation of nanosheets in polymer matrices. In this report, multilayer films were successfully fabricated by layer-by-layer assembly of regenerated cellulose and graphene oxide, in which graphene oxide nanosheets were used as the building blocks. The thickness of 50 layer film is about 20 μm and it exhibits a high degree of smoothness. This may be attributed to the well-defined layered structure with high degree of planar orientation and nanolevel assemblies of graphene oxide nanosheets in the polymer matrices. Typical field emission scanning electron microscope images demonstrate an ordered arrangement of layers. The electrical conductivity of the multilayer films shows a remarkable increase with increasing layer of the films. A significant enhancement of mechanical properties has been achieved, that is, a 110.8% improvement of elastic modulus and a 262.5% increase of hardness respectively.

International audience; A tunable strategy, based on the combination of Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) and the Layer by Layer (LbL) deposition of polyelectrolytes, was exploited to design tailor-made polyelectrolyte multilayers (PEM) with unusual nanometric features. The cornerstone of the approach is to use polyelectrolytes grafted onto a planar inorganic substrate with different chain conformations as a template for depositing PEM. More particularly, tethered poly(trimethylammonium ethyl methacrylate iodide) (PTMAEMAI) grafts provide various 3D distributions of charge due to a conformation transition of the precursor quaternizable poly(N, N-dimethylamino)ethyl methacrylate (PDMAEMA) chains from 'pancake' to brush-like regime. The change of regime was ensured through the controlled variation of the graft molecular weight using SI-ATRP. The regions made of attached-polycations may serve as preferential positively charged anchoring sites and act as structure-directing agents for the subsequent LbL self-assembly of poly(sodium 4-styrenesulfonate) (PSS)/poly(diallyldimethylammonium chloride) (PDADMAC) multilayers. We have revealed the possibility to fine manipulate (i) the interaction abilities and (ii) the topology of (PSS/PDADMAC) films through the spatial organization exhibited by the PTMAEMAI grafts. This appears as a well-suited and straightforward tool to create an adjustable nanoscale patterning of the resulting multilayers.

When aqueous solutions of polycations and polyanions are mixed, polyelectrolyte complexes form. These are usually insoluble in water, so that they separate out as a new concentrated polymer phase, called a complex coacervate. The behavior of these complexes is reviewed, with emphasis on new measurements that shed light on their structural and mechanical properties, such as cohesive energy, interfacial tension, and viscoelasticity. It turns out that stoichiometric complexes can be considered in many respects as pseudo-neutral, weakly hydrophobic polymers, which are insoluble in water, but become progressively more soluble as salt is added. In fact, the solubility-enhancing effect of salt is quite analogous to that of temperature for polymers in apolar solvents. Since two-phase systems can be prepared in colloidal form, we also discuss several kinds of colloids or 'microphases' that can arise due to polyelectrolyte complexation, such as thin films, 'zipper' brushes, micelles, and micellar networks. A characteristic feature of these charge-driven two-phase systems is that two polymeric ingredients are needed, but that some deviation from strict stoichiometry is tolerated. This turns out to nicely explain how and when the layer-by-layer method works, how a 'leverage rule' applies to the density of the 'zipper brush', and why soluble complexes or micelles appear in a certain window of composition. As variations on the theme, we discuss micelles with metal ions in the core, due to incorporation of supramolecular coordination polyelectrolytes, and micellar networks, which form a new kind of physical gels with unusual properties.

This article is part of the Supramolecular Chemistry at Interfaces special issue. The layer-by-layer (LbL) assembly of salt-containing nonstoichiometric polyelectrolyte complexes (PECs) with oppositely charged uncomplexed polyelectrolyte for the fabrication of dewetting-induced porous polymeric films has been systematically investigated. Salt-containing poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) complexes (noted as PAH-PAA) with a molar excess of PAH were LbL assembled with polyanion poly(sodium 4-styrenesulfonate) (PSS) to produce PSS/PAH-PAA films. The structure of the PAH-PAA complexes is dependent on the concentration of NaCl added to their aqueous dispersions, which can be used to tailor the structure of the LbLassembled PSS/PAH-PAA films. Porous PSS/PAH-PAA films are fabricated when salt-containing PAH-PAA complexes with a large amount of added NaCl are used for LbL assembly with PSS. In-situ and ex-situ atomic force microscopy measurements disclose that the dewetting process composed of pore nucleation and pore growth steps leads to the formation of pores in the LbL-assembled PSS/PAH-PAA films. The present study provides a facile way to fabricate porous polymeric films by dewetting LbL-assembled polymeric films comprising salt-containing PECs. Refereed/Peer-reviewed

In this paper, we numerically demonstrate mid-IR nearly perfect resonant absorption and coherent thermal emission for both polarizations and wide angular region using multilayer designs of unpatterned films of hexagonal boron nitride (hBN). In these optimized structures, the films of hBN are transferred onto a Ge spacer layer on top of a one-dimensional photonic crystal (1D PC) composed of alternating layers of KBr and Ge. According to the perfect agreements between our analytical and numerical results, we discover that the mentioned optical characteristic of the hBN-based 1D PCs is due to a strong coupling between localized photonic modes supported by the PC and the phononic modes of hBN films. These coupled modes are referred as Tamm phonons. Moreover, our findings prove that the resonant absorptions can be red-or blue-shifted by changing the thickness of hBN and the spacer layer. The obtained results in this paper are beneficial for designing coherent thermal sources, light absorbers, and sensors operating within 6.2 mu m to 7.3 mu m in a wide angular range and both polarizations. The planar and lithography free nature of this multilayer design is a prominent factor that makes it a large scale compatible design. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

The layer-by-layer (LbL) adsorption technique allows construction of polyelectrolyte (PE) multilayer films with precisely defined properties and that opens a wide range of applications, where such materials can be used. One of the most important factors governing structure and interfacial properties of polyelectrolyte films is electrolyte concentration and pH of the PE solutions. In the present work we have focused our attention on multilayer films formed using combination of weak polyelectrolytes, PAH/PAA, whose charge can be tuned during the film preparation by pH of their solutions. PE films were formed by LbL technique on silicon wafers, Si/SiO 2 , and were characterized by ellipsometry, neutron reflectometry and AFM. Additionally quartz crystal microbalance (QCM) was used to determine mass of the films formed on the gold covered QCM crystals. We have found that the thickest films were formed when both polyelectrolytes were weakly charged, while the thinnest films were obtained for fully charged PAH and PAA. However, for the combination of weakly and strongly charged polyelectrolyte the non-monotonic increase of film thickness with a number of deposited PE layers was observed. We hypothesize, that it results from PE reorganization and formation of surface complexes during adsorption of polyelectrolyte layers.

The irreversibility temperatures were measured for a-axis oriented and c-axis in-plane aligned Y123/Pr123 multilayer films in various magnetic fields. Pr123 layers act as two-dimensional (planer) c-axis correlated artificial pinning centers (APCs) in the multilayer films. In the irreversibility field-temperature (B irr - T) curves, the crossover was observed near matching field B phi for the multilayer films, when the magnetic fields were applied parallel to the c -axis of the film (B//c). It is suggested the vortex state in Y123 films with two-dimensional APCs is Bose glass below the crossover field. The B irr - T curves under B // a shifted toward lower temperature and magnetic field regions.

Noncharged pyrene molecules were incorporated into multilayer films by first loading pyrene into poly(acrylic acid) (PAA)-stabilized cetyltrimethylammonium bromide (CTAB) micelles (noted as PAA&(Py@CTAB)) and then layer-by-layer (LbL) assembled with poly(diallyldimethylammonium chloride) (PDDA). The stable incorporation of pyrene into multilayer films was confirmed by quartz crystal microbalance (QCM) measurements and UV−vis absorption spectroscopy. The resultant PAA&(Py@CTAB)/PDDA multilayer films show an exponential growth behavior because of the increased surface roughness with increasing number of film deposition cycles. The present study will open a general and cost-effective avenue for the incorporation of noncharged species, such as organic molecules, nanoparticles, and so forth, into LbL-assembled multilayer films by using polyelectrolyte-stabilized surfactant micelles as carriers.

Técnicas FT-IR de transmissão, reflexão atenuada (ATR), reflexão difusa (DRIFT), microscopia acoplada ao FT-IR (MIC/FT-IR) e detecção fotoacústica (PAS) foram utilizadas para a caracterização de filmes multicamadas. As técnicas ATR, MIC/FT-IR e PAS apresentaram os melhores resultados, provavelmente em função da possibilidade de análise somente da superfície das amostras com cristal (ATR), análise de cada camada da amostra separadamente (MIC/FT-IR) e possibilidade de variação da velocidade de obtenção do espectro (PAS). Dados de análises de microscopia ótica (MO) e calorimetria exploratória diferencial (DSC) foram usados, associados aos dados FT-IR, para a caracterização completa dos materiais.The transmission, reflection, photoacoustic (PAS) and microscopy FT-IR techniques have been used for characterizing multilayer films. The ATR, microscopy FT-IR and PAS techniques showed better results, probably because it was possible to analyze only the sample surface by ATR, while with MIC/FT-IR each layer of the sample could be studied separately and in PAS the spectra could be obtained at different rates. A complete characterization for the films was achieved by combining with optical microscopy, DSC and FT-IR data.

Interactions of native DNA with octadecylamine (ODA) and hexadecymdimethylammonium bromide (HTAB) monolayers at the air/water interface were studied by pi-A isotherms, ellipsometry, and X-ray reflectivity. We show that the microscopic structure of ODA-DNA complexes is definitely consistent with a single-stranded form for DNA. On the contrary, with HTAB, DNA complexes in its native form. The crucial difference in the behavior of these two fairly similar lipids is due to the presence of the amine group in ODA. These results should be relevant to applications such as DNA chips and sensors.

The adsorption of quaternized poly(vinylpyridine) (QPVP) on controlled pore glass (CPG) size, over the ionic strength range 0.001-0.5 M was found to display nonmonotonic behavior as a function of pore size. Both adsorption kinetics and ionic strength effects deviated dramatically from behavior typical of adsorption on flat surfaces when the ratio of the pore radius Rp to the polymer hydrodynamic radius Rh became smaller than ca. 2. Ionic strength enhancement of adsorption for small pore sizes was observed at much higher salt concentrations than is typical for polycation adsorption on flat surfaces. The amount of polymer adsorbed per unit surface area of glass GammaA, in 0.5 M NaCl, exhibited a shallow maximum at Rp/Rh approximately 5. Since the value of GammaA for small pore size CPG is strongly depressed by the large surface area, an alternative and more interesting observation is that the amount of polymer adsorbed per gram of CPG, Gammaw, displays a strong maximum when Rp is equal to or slightly smaller than Rh. The efficiency with which QPVP binds anionic micelles to (negatively charged) CPG (grams of surfactant/grams of QPVP) increases strongly with diminishing pore size, indicating that the configuration of polycation bound to small pores favors micelle binding. Since the micelles are larger than small pores, the results indicate that when RpRh, adsorbed polycation molecules reside only partially within the pore. The results of this study are supported by simulations of polyelectrolytes within cylindrical cavities.

In recent decades, polymers have experienced a radical evolution: from being used as inexpensive materials in the manufacturing of simple appliances to be designed as nanostructured devices with important applications in many leading fields, such as biomedicine at the nanoscale. Within this context, polymeric free-standing nanomembranes - self-supported quasi-2D structures with a thickness ranging from similar to 10 to a few hundreds of nanometers and an aspect ratio of size and thickness greater than 10(6) - are emerging as versatile elements for applications as varied as overlapping therapy, burn wound infection treatment, antimicrobial platforms, scaffolds for tissue engineering, drug-loading and delivery systems, biosensors, etc. Although at first, a little over a decade ago, materials for the fabrication of free-standing nanosheets were limited to biopolymers and insulating polymers that were biodegradable, during the last five years the use of electroactive conducting polymers has been attracting much attention because of their extraordinary advantages in the biomedical field. In this context, a systematic review of current research on polymeric free-standing nanomembranes for biomedical applications is presented. Moreover, further discussion on the future developments of some of these exciting areas of study and their principal challenges is presented in the conclusion section.

TSeveral polymers can be combined in one multilayer structure by reactive coextrusion. Tie-layers are often used to compatibilize adjacent layers and may reduce or suppress interfacial instabilities and defects in multilayer coextrusion flow. However, a new additional defect defined as “grainy” defect can be observed. In our best of knowledge, no study in literature has been dedicated to understand its origin. The phenomena are quite complex due to the coupling of the effects of flow and the physico-chemical mechanisms at the interface. The aim of this work is to understand the relationship between the instabilities and defects encountered in multilayer coextruded films and the role of the copolymer formed in-situ between tie and barrier layers. Polyamide 6 (PA6) and ethylene-vinyl alcohol copolymer (EVOH) were used as barrier layers sandwiched in polypropylene (PP) with or without tie-layer based on polypropylene grafted maleic anhydride (PP-g-MA). Influence of process parameters and nature of the polymer pair on the generation of “grainy” defect has been assessed and related to the rheological and the physico-chemical properties of layers. These experiments showed that this defect appeared mainly in the compatibilized EVOH system and could be distinguished from the usual coextrusion instabilities. Interfacial properties between tie and barrier layers have been investigated. Shear stress relaxation experiments have been carried out on reactive tie/barrier bilayers. Due to the interphase generated in-situ, the relaxation behavior was altered by extending the relaxation time. Investigation of interfacial morphology highlighted that the copolymer architecture significantly affected the interface/interphase development and interface roughness. Hence, relationships between relaxation process, interfacial morphology and copolymer structure were correlated with the generation of grainy defects in coextrusion.

International audience; Layer by Layer (LbL) thin films stemming from the formation of stereocomplex between oligolactate of opposite chirality (OLLA and ODLA) covalently anchored onto poly(vinyl alcohol) (PVA) chains is described herein for the first time. The feasibility to construct films by sequential adsorption of PVA-g-ODLA and PVA-g-OLLA graft copolymers is undertaken through the exploitation of two different film deposition techniques, namely dip-and spin-assisted processes. For both deposition methods, infrared spectroscopy in ATR mode reveals a progressive accumulation of matter on the flat substrate during the successive cycle depositions and proves that co-crystallisation involving the two homochiral copolymers is the main driving force for the step by step film build up. Also, the effect of the deposition technique is assessed on the film features in terms of (i) growth mechanism, (ii) internal organization and (iii) surface topology. The strong centrifugal forces associated with fast solvent elimination acting during spinning lead to thinner film with more uniform and homogeneous surface morphology in a much shorter time, than the ones resulting from the dip-assisted process. Such LbL nanometric films, induced by OLLA/ODLA interfacial stereocomplexation, open promising perspectives in the field of biodegradable self-assembled films.

The barrier performance of multilayer polymeric films for food applications has been significantly improved by incorporating oxygen scavenging materials. The scavenging activity depends on parameters such as diffusion coefficient, solubility, concentration of scavenger loaded and the number of available reactive sites. These parameters influence the barrier performance of the film in different ways. Virtualization of the process is useful to characterize, design and optimize the barrier performance based on physical configuration of the films. Also, the knowledge of values of parameters is important to predict the performances. Inverse modeling and sensitivity analysis are sole way to find reasonable values of poorly defined, unmeasured parameters and to analyze the most influencing parameters. Thus, the objective of this work was to develop a model to predict barrier properties of multilayer film incorporated with reactive layers and to analyze and characterize their performances. Polymeric film based on three layers of Polyethylene terephthalate (PET), with a core reactive layer, at different thickness configurations was considered in the model. A one dimensional diffusion equation with reaction was solved numerically to predict the concentration of oxygen diffused into the polymer taking into account the reactive ability of the core layer. The model was solved using commercial software for different film layer configurations and sensitivity analysis based on inverse modeling was carried out to understand the effect of physical parameters. The results have shown that the use of sensitivity analysis can provide physical understanding of the parameters which highly affect the gas permeation into the film. Solubility and the number of available reactive sites were the factors mainly influencing the barrier performance of three layered polymeric film. Multilayer films slightly modified the steady transport properties in comparison to net PET, giving a small reduction in the permeability and oxygen transfer rate values. Scavenging capacity of the multilayer film increased linearly with the increase of the reactive layer thickness and the oxygen absorption reaction at short times decreased proportionally with the thickness of the external PET layer.

Herein, hydroxypropyl-beta-cyclodextrin (HP beta CD) inclusion complex (IC) of a hydrophobic drug, sulfisoxazole (SFS) was incorporated in hydroxypropyl cellulose (HPC) nanofibers (HPC/SFS/HP beta CD-IC-NF) via electrospinning. SFS/HP beta CD-IC was characterized by DSC to investigate the formation of inclusion complex and the stoichiometry of the complex was determined by Job's plot. Modeling studies were also performed on SFS/HP beta CD-IC using ab initio technique. SEM images depicted the defect free uniform fibers and confirmed the incorporation of SFS/HP beta CD-IC in nanofibers did not alter the fiber morphology. XRD analyses showed amorphous distribution of SFS/HP beta CD-IC in the fiber mat. Release studies were performed in phosphate buffered saline (PBS). The results suggest higher amount of SFS released from HPC/SFS/HP beta CD-IC-NF when compared to free SFS containing HPC nanofibers (HPC/SFS-NF). This was attributed to the increased solubility of SFS by inclusion complexation. Sandwich configurations were prepared by placing HPC/SFS/HP beta CD-IC-NF between electrospun PCL nanofibrous mat (PCL-HPC/SFS/HP beta CD-IC-NF). Consequently, PCL-HPC/SFS/HP beta CD-IC-NF exhibited slower release of SFS as compared with HPC/SFS/HP beta CD-IC-NF. This study may provide more efficient future strategies for developing delivery systems of hydrophobic drugs. (C) 2015 Elsevier B.V. All rights reserved.

A mathematical model that predicts the water-permeability coefficient of multilayer films intended for food-packaging applications is presented. A 6-layer film composed of 5 polyolefinic layers and a layer made of a copolymer of ethylene and vinylalcohol (EVOH) was used to validate the proposed model. Water-permeability tests were run at 25°C both on each single layer and on the multilayer film; whereas the water-sorption isotherm and the water-sorption kinetics were determined only for the EVOH layer. Results suggest that the water-permeability coefficient of multilayer films can be predicted from the knowledge of the water-transport properties of each constituent layer.

Adsorption characteristics of a random copolymer of poly(ethylene oxide) monomethyl ether methacrylate and methacryloxyethyl trimethylammonium chloride (PEOMENIA:METAC) on silica were studied using stagnation point adsorption reflectometry (SPAR), quartz crystal microbalance with dissipation (QCM-D), and contact angle techniques. The PEOMEMA:METAC copolymer used in this study is a low charge density polyelectrolyte, with 2% of the monomer units carrying permanent positive charges and 98% containing poly(ethylene oxide) side chains that are approximately 45 repeating units long. The surface excess was determined as a function of pH and concentration of indifferent electrolyte. It was found that the presence of a small amount of 1: 1 electrolyte decreases the adsorbed amount significantly. Further, increasing the pH at a constant ionic strength, 10 mM, results in decreasing surface excess. It is suggested that the adsorption is realized via a combination of non-Coulomb interactions between the poly(ethylene oxide), PEO, grafts and protonated silanol groups at the silica-solution interface and an electrostatic interaction between the charged segments and the oppositely charged surface. Increasing pH and/or salt concentration results in progressive charging of the silica surface with the consequent decrease in affinity between silica and PEO, explaining the decrease in the adsorbed amount of the polymer.

Researchers developed ultrathin high-performance capacitors using LEGO-like game of oxide nanosheets., MANA E-BULLETIN. 13 (2014)

In a marine environment, specific proteins are secreted by mussels and used as a bioglue to stick to a surface. These mussel proteins present an unusual amino acid 3,4-dihydroxyphenylalanine (known as DOPA). The outstanding adhesive properties of these materials in the sea harsh conditions have been attributed to the presence of the catechol groups present in DOPA. Inspired by the structure and composition of these adhesive proteins, we used dopamine-modified hyaluronic acid (HA-DN) prepared by carbodiimide chemistry to form thin and surface-adherent dopamine films. This conjugate was characterized by distinct techniques, such as nuclear magnetic resonance and ultraviolet spectrophotometry. Multilayer films were developed based on chitosan and HA-DN to form polymeric coatings using the layer-by-layer methodology. The nanostructured films formation was monitored by quartz crystal microbalance. The film surface was characterized by atomic force microscopy and scanning electron microscopy. Water contact angle measurements were also conducted. The adhesion properties were analyzed showing that the nanostructured films with dopamine promote an improved adhesion. In vitro tests showed an enhanced cell adhesion, proliferation and viability for the biomimetic films with catechol groups, demonstrating their potential to be used in distinct biomedical applications., The authors want to acknowledge the COST Action TD0906 - Biological adhesives: from biology to biomimetics. The authors also acknowledge the financial support from the Fundacao para a Ciencia e para a Tecnologia through the Ph.D. grants with the references SFRH/BD/73119/2010 and SFRH/BD/69529/2010. G. G. Ferrer acknowledges the support of the Spanish Ministry of Science and Innovation for the mobility grant JC2008-00135. G. Botelho acknowledges the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho).

Complex formation between 4-(10,12-pentacosadiynamidomethyl)pyridine and metal ions in the subphase results in stable Langmuir monolayers up to surface pressures of 35 mN m(-1). Electron microscopy pictures show a flat monomer monolayer before polymerization and a polymer monolayer exhibiting a more striated structure after polymerization. Multilayers of the amphiphile can only be built up after complexation with metal ions. X-ray photoelectron spectroscopy (XPS) measurements definitely confirm the presence of metal ions in the multilayers, and the molar ratio between metal and amphiphile is derived from the spectra. These multilayers are further characterized by means of small-angle X-ray reflection measurements and Fourier transform infrared (FT-IR) spectroscopy, which show that the amphiphile has a large tilt angle (a) with respect to the surface normal. The multilayers are polymerized by means of UV irradiation, and UV-vis spectroscopy is used to study the polymerization process. The structural changes during polymerization are deduced from small-angle X-ray reflection measurements and FT-IR spectroscopy. In all cases, the bilayer spacing decreases during the polymerization process, whereas in some cases the regular plane of the all-trans conformation of the alkyl chains is converted to an irregular one containing gauche conformations. For multilayers built up from a CuCl2-containing subphase, the whole distinct layer structure is destroyed during the polymerization process.

Publicado em "Journal of Tissue Engineering and Regenerative Medicine", vol. 7, supp. 1 (2013), Some marine species, such as mussels, can strongly attach themselves to rocks in the diffficult conditions of the sea. In fact, marine mussels secrete adhesive proteins that show a high adhesion to both inorganic and organic surfaces in aqueous environments. These proteins have an amino acid designated as 3,4-dihydroxy-L-phenylalanine (DOPA) which in turn possesses catechol groups that are primarily responsible for these strong adhesive bonds. Inspired by this behaviour, layer-by-layer (LbL) films based on polymers that contain catechol groups were developed. It is expected that such materials will present an enhanced cell adhesion when they are applied in biomedical applications. Dopamine-modified hyaluronic acid (HA-DN), which possesses catechol groups, was prepared by carbodiimide chemistry. This conjugate was characterized by distinct techniques, such as nuclear magnetic resonance (NMR) and ultra-violet spectrophotometry (UV). Then films were developed based on chitosan (CHT) and HA-DN using the Layer-by-Layer (LbL) technique. The formation of these films was investigated in-situ by quartz crystal microbalance with dissipation monitoring (QCM-D). The adhesion properties of the coatings were also analyzed. In vitro tests using distinct cell sources revealed an enhanced cell adhesion, proliferation and viability for the films that contain catechol groups, which demonstrates their potential to be used in biomedical applications.

Molecularly thin two-dimensional crystals can alleviate the lattice matching restrictions of epitaxial crystalline thin film growth, as reported by researchers in Japan., MANA E-BULLETIN. 8 (2013)