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Magnetometry and ferromagnetic resonance are used to quantitatively study magnetic anisotropy with an easy axis both in the film plane and perpendicular to it. In the study of single-layer and multilayer permalloy films, it is demonstrated that these methods make it possible not only to investigate the average field of perpendicular and in-plane anisotropy, but also to characterize their inhomogeneity. It is shown that the quantitative data from direct integral and local measurements of magnetic anisotropy are consistent with the direct and indirect estimates based on processing of the magnetization curves. The possibility of estimating the perpendicular magnetic anisotropy constant from the width of stripe domains in a film in the transcritical state is demonstrated. The average in-plane magnetic anisotropy field of permalloy films prepared by magnetron sputtering onto a Corning glass is almost unchanged with the thickness of a single-layer film. The inhomogeneity of the perpendicular anisotropy field for a 500 nm film is greater than that for a 100 nm film, and for a multilayer film with a total permalloy thickness of 500 nm, it is greater than that for a homogeneous film of the same thickness. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Hypothesis: The self-assembly of amphiphilic molecules onto solid substrates can result both in the formation of monolayers and multilayers. However, on oxidized and non-oxidized copper (Cu), only monolayer formation was reported for phosphonic acids possessing one phosphate head group. Here, the adsorption of octadecylphosphonic acid (ODPA) on Cu substrates through a self-assembly process was investigated with the initial hypothesis of monolayer formation. Experiments: The relative amount of ODPA adsorbed on a Cu substrate was determined by infrared reflection/absorption spectroscopy (IRRAS) and by atomic force microscopy (AFM) investigations before and after ODPA deposition. X-ray photoelectron spectroscopy (XPS) with sputtering was used to characterize the nature of the layers. Findings: The results show that the thickness of the ODPA layer increased with deposition time, and after 1 h a multilayer film with a thickness of some tens of nm was formed. The film was robust and required long-time sonication for removal. The origin of the film robustness was attributed to the release of Cu ions, resulting in the formation of Cu-ODPA complexes with Cu ions in the form of Cu(I). Preadsorbing a monolayer of octadecylthiol (ODT) onto the Cu resulted in no ODPA adsorption, since the release of Cu(I) ions was abolished. © 2020 Elsevier Inc., QC 20201202

[EN] The present research reports on the development of bi- and multilayer polylactide (PLA) films by the incorporation of electrospun nanostructured PLA coatings and interlayers containing the antioxidant gallic acid (GA) at 40 wt% onto cast-extruded PLA films. To achieve the bilayer structures, submicron GA-loaded PLA fibers were applied on 200-µm cast PLA films in the form of coatings by electrospinning for 1, 2, and 3 h. For the multilayers, the cast PLA films were first coated on one side by electrospinning, then sandwiched with 10-µm PLA film on the other side, and the resultant whole structure was finally thermally post-treated at 150 ºC without pressure. Whereas the bilayer PLA films easily delaminated and lacked transparency, the multilayers showed sufficient adhesion between layers and high transparency for deposition times during electrospinning of up to 2 h. The incorporation of GA positively contributed to delaying the thermal degradation of PLA for approximately 10 ºC, as all films were thermally stable up to 345 ºC. The in vitro release studies performed in saline medium indicated that the GA released from the bilayer PLA films rapidly increased during the first 5 h of immersion while it stabilized after 45¿250 h. Interestingly, the PLA multilayers offered a high sustained release of GA, having the capacity to deliver the bioactive for over 1000 h. In addition, in the whole tested period, the GA released from the PLA films retained most of its antioxidant functionality. Thus, during the first days, the bilayer PLA films can perform as potent vehicles to deliver GA while the multilayer PLA films are able to show a sustained release of the natural antioxidant for extended periods

The present research reports on the development of bi- and multilayer polylactide (PLA) films by the incorporation of electrospun nanostructured PLA coatings and interlayers containing the antioxidant gallic acid (GA) at 40 wt% onto cast-extruded PLA films. To achieve the bilayer structures, submicron GA-loaded PLA fibers were applied on 200-µm cast PLA films in the form of coatings by electrospinning for 1, 2, and 3 h. For the multilayers, the cast PLA films were first coated on one side by electrospinning, then sandwiched with 10-µm PLA film on the other side, and the resultant whole structure was finally thermally post-treated at 150 °C without pressure. Whereas the bilayer PLA films easily delaminated and lacked transparency, the multilayers showed sufficient adhesion between layers and high transparency for deposition times during electrospinning of up to 2 h. The incorporation of GA positively contributed to delaying the thermal degradation of PLA for approximately 10 °C, as all films were thermally stable up to 345 °C. The in vitro release studies performed in saline medium indicated that the GA released from the bilayer PLA films rapidly increased during the first 5 h of immersion while it stabilized after 45–250 h. Interestingly, the PLA multilayers offered a high sustained release of GA, having the capacity to deliver the bioactive for over 1000 h. In addition, in the whole tested period, the GA released from the PLA films retained most of its antioxidant functionality. Thus, during the first days, the bilayer PLA films can perform as potent vehicles to deliver GA while the multilayer PLA films are able to show a sustained release of the natural antioxidant for extended periods.

Iron-gallium (FeGa) thin film has the unique advantages in designing integrated magnetic sensors or chips due to its relatively large magnetostrictive constant compared with other soft magnetic materials. In this work, non-magnetic doping and laminating methods have been employed to control the magnetic and electric properties of this alloy film. By doping a certain amount of boron (B), the coercivities are largely decreased for samples of thickness less than ~30 nm. For thicker films, we find that inserting an ultrathin Al 2 O 3 middle layer is very helpful to control the coercivities with negligible influence on saturation magnetization (M s ). The smallest easy-axis coercivity of 0.98×79.6 A/m is obtained in the multilayer film FeGaB(25 nm)/Al 2 O 3 (0.5 nm)/FeGaB(25 nm). In this case, the resistivity is enhanced by 1.5 times compared with the 50 nm single layer film. Structural characterizations indicate the reductions of crystalline quality and physical dimension of the magnetic grains playing important roles in softening the magnetic properties. Besides, the influences of magnetostatic interaction and morphology characteristics are also considered in facilitating domain reversal. High permeability spectra with gigahertz response are obtained for our multilayer films. The methodology applied here, i. e., enhancing magnetic and electric performance by introducing ultrathin non-magnetic layers, could be translated to other species of soft magnetic materials as well., QC 20190415

U okviru ove doktorske disertacije izvršeno je formiranje polietilenskih/polikaprolaktonskih (PE/PCL) hibridnih materijala na bazi nanoceluloze i metalnih oksida. Rad je podeljen na četiri celine. U prvoj je sintetisana i okarakterisana nanoceluloza NC i modifikovana nanoceluloza NCMA i formirani su kompoziti na bazi gvožđe oksida NC-Fe3O4 i NCMA-Fe3O4. U drugom delu su formirani i ispitani dvoslojni hibridni filmovi PE/PCL sa kompozitima NC-Fe3O4 i NCMA-Fe3O4 u polikaprolaktonskom sloju. U trećem delu je sintetisana i okarakterisana nanoceluloza NC i modifikovana nanoceluloza NCMA i formirani su kompoziti na bazi bakar (II) oksida NC-CuO i NCMA-CuO i u četvrtom su formirani i ispitani dvoslojni hibridni filmovi PE/PCL sa kompozitima NC-CuO i NCMA-CuO u polikaprolaktonskom sloju. U prvom delu disertacije su sintetisani kompoziti nanoceluloza-magnetit (NC-Fe3O4) i maleinskom kiselinom funkcionalizovana nanoceluloza/magnetit (NCMA-Fe3O4), a zatim upotrebljeni kao punioci u polikaprolaktonskom sloju (PLC) pri različitim koncentracijama (5, 10 i 15 mas%). Kompozitnim materijalima nanoceluloza-magnetit su najpre proučavane strukturne, morfološke i termalne karakteristike, a nakon toga su inkorporirani u PCL sloj. Strukturna analiza izvršena je na osnovu rezultata dobijenih primenom rendgenske difrakcione analize (XRD) i infracrvene spektroskopije sa Furijeovom transformacijom (FTIR). Morfološka svojstva su proučavana skenirajućom elektronskom mikroskopijom (SEM). Termička svojstva su ispitana primenom termogravimetrijske analize. U drugom delu disertacije, polikaprolaktonski sloj sa puniocima je nanet na površinu polietilenske folije i ispitana su barijerna svojstva dobijenih hibridnih dvoslojnih filmova. Dodatak filera (punilaca) ne narušava prvobitna svojstva polimernog sloja, naročito u pogledu njegovih barijernih svojstava..., Synthesis and characterization of polyethylene/polycaprolactone-modified nanocellulose hybrid materials containing different metal oxides was performed. The work is divided into four parts, and the first is a synthesized and characterized NC nanocellulose and modified NCMA nanocellulose, and composites based on iron oxide NC-Fe3O4 and NCMA- Fe3O4 are formed. In the second part, two-layer hybrid PE/PCL films were formed and tested with NC- Fe3O4 and NCMA- Fe3O4 composites in a polycaprolactone layer. In the third part, NC nanocellulose NC and modified NCMA nanocellulose were synthesized and characterized by copper (II) oxide NC-CuO and NCMA-CuO composites, and in the fourth, two-layer hybrid PE/PCL films were formed with NC-CuO and NCMA-CuO in a polycrystalline layer. Nanonocelulose/magnetite (NC-Fe3O4) nanocomposite and maleic acid functionalized NC/magnetite (NCMA-Fe3O4) nanocomposite were prepared and used as filler at various concentrations (5, 10 and 15 wt. %) in polycaprolactone (PCL) layer. The structural, morphological and thermal properties were investigated, upon composite materials were incorporated in PCL layer. Structural properties of composites were investigated by using FT–IR (Fourier transform infrared spectroscopy) and XRD analysis. The morphological properties were investigated by SEM (scanning electron microscopy). The second part of the thesis was focused on characterization of hybrid multicomponent films containing Fe3O4 nanoparticles. Polycaprolactone filled with nanocellulose/magnetite composites were coated on LDPE layer and barrier properties of low-density polyethylene/polycaprolactone-modified nanocellulose hybrid materials were investigated...

Urea (bonded) cross-linked multilayer thin film by sequential deposition of bifunctional and tetrafunctional molecular building blocks was demonstrated. Multilayer growth as a function of deposition cycles was inspected using UV-vis absorption spectroscopy. From IR results, three characteristic infrared bands of amide I, amide II, and asymmetric ν_a (N-C-N) stretching band confirmed the formation of polyurea networks by alternate dipping into solutions of amine and isocyanate functionalities monomers. The deconvoluted component from the C 1s and N 1s spectra from X-ray photoelectron spectroscopy (XPS) shows clear evidence of stable polyurea networks. Enhancement of structural periodicity with film growth was demonstrated by grazing incidence small angle X-ray scattering (GI-SAXS) measurements. The thin film near the substrate surface seems to have an amorphous structure. However, molecular ordering improves in the surface normal direction of the substrate with a certain number of deposited layers. Constant mass density was not observed with deposition cycles. The mass density increased upto 16% within deposited layers from proximate layers to those extending away from the substrate surface. This difference in packing density might derive from the different degrees of cross-linking among layers proximate to the substrate surface and extending away from the surface.

The differential swelling and bending of multilayer polymeric films due to the dissimilar uptake of volatile organic compounds (VOCs; n-hexane, limonene) in the different layers was studied. Motions of thin polyethylene films triggered by the penetrant were investigated to learn more about how their deformation is related to VOC absorption. Single layers of metallocene or low-density polyethylene, and multilayers (2-288-layers) of these in alternating positions were considered. Single-, 24-, and 288 layer films displayed no motion when uniformly subjected to VOCs, but they could display simple curving modes when only one side of the film was wetted with a liquid VOC. Two-layer films displayed simple bending when uniformly subjected to VOCs due to the different swelling in the two layers, but when the VOC was applied to only one side of the film, more complex modes of motion as well as dynamic oscillations were observed (e.g., constant amplitude wagging at 2 Hz for ca. 50 s until all the VOC had evaporated). Diffusion modeling was used to study the transport behavior of VOCs inside the films and the different bending modes. Finally a prototype VOC sensor was developed, where the reproducible curving of the two-layer film was calibrated with n-hexane. The sensor is simple, cost-efficient, and nondestructive and requires no electricity., QC 20211027

The properties of Ni x Mn 100-x /Fe 20 Ni 80 multilayer structures with exchange bias were systematically studied. The influence of composition of Ni x Mn 100-x pinning layers, annealing temperature on crystalline film structures, exchange bias field and coercive force of Fe 20 Ni 80 pinned layers were comparatively analyzed. It was found that the multilayer films with Ni-Mn pinning layer containing some 30 wt.% Ni have the most suitable combination of exchange bias and magnetic hysteresis properties for their technical applications. © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.

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.

In this paper, we study a magnetic impedance characteristics of film multilayer elements of the strip type [Ti / FeNi] 5 / Ti / Cu / Ti / (FeNi / Ti) x, x = 0...5, prepared by magnetron sputtering. We observed in these structures similar type of magnetization reversal in an array of layers between the substrate and the central conductive layer of copper for all the samples and changing the type of magnetization reversal in the array of the conductive layer of copper with a decrease in the number of upper magnetic layers. Despite the fact that the absolute maximum MI ratio amounted impedance ΔZ / Z = 126% for a symmetrical structure, an asymmetrical structure with four magnetic layers above the layer of copper also has high MI ratio ΔZ / Z = 121% in the lower fields, which allows to recommend asymmetric structure for the subsequent functionalization of the upper layer in detectors of weak magnetic fields., В данной работе исследуются особенности магнитного импеданса плёночных многослойных элементов в форме полос типа [Ti/FeNi]5/Ti/Cu/Ti/(FeNi/Ti)x, x = 0…5, полученных магнетронным распылением. На полученных структурах наблюдался сходный тип перемагничивания в массиве слоев между подложкой и центральным проводящим слоем меди для всех образцов и смена типа перемагничивания в массиве над проводящим слоем меди при уменьшении количества верхних магнитных слоев. Несмотря на то, что абсолютный максимум МИ соотношения импеданса составил ∆Z/Z=126% для симметричной структуры, асимметричная структура с 4 магнитными слоями над слоем меди также обладает высоким МИ соотношением ∆Z/Z=121% в меньших полях, что позволяет рекомендовать асимметричную структуру для последующей функционализации верхнего слоя в детекторах слабых магнитных полей.

The effects of exchange coupling on magnetic switching properties of all-garnet multilayer thin film structures are investigated. All-garnet structures are fabricated by sandwiching a magneto-soft material of composition type Bi1.8Lu1.2Fe3.6Al1.4O12 or Bi3Fe5O12:Dy2O3 in between two magneto-hard garnet material layers of composition type Bi2Dy1Fe4Ga1O12 or Bi2Dy1Fe4Ga1O12:Bi12O3. The fabricated RF magnetron sputtered exchange-coupled all-garnet multilayers demonstrate a very attractive combination of magnetic properties, and are of interest for emerging applications in optical sensors and isolators, ultrafast nanophotonics and magneto-plasmonics. An unconventional type of magnetic hysteresis behavior not observed previously in magnetic garnet thin films is reported and discussed.

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., Peer Reviewed, Postprint (author's final draft)

Layer-by-layer (LbL) assembled films and capsules have shown potential application in diverse fields such as energy and drug delivery, because they can be prepared from various polymers and loaded with numerous materials. Although film deposition on planar substrates can be rapid and facile using techniques such as spray-coating or spin-coating, the layering of particles generally requires longer and more involved protocols. LbL assembly on particles typically uses random diffusion as the adsorption driving force, which can lead to the risk of aggregation during layering and washing. To overcome the inherent challenges surrounding polymer deposition on particulate matter, immobilization techniques for suspending the template particles were developed. Immobilizing the template particles has allowed for rapid, facile, and automated layering methods to be applied to particles of varying sizes and compositions. Large particles were suspended in a liquid-based fluidized bed for layering, while smaller particles required immobilization in a porous hydrogel before facile layering was possible. The use of a fluidized bed allowed for the large scale production of polymer microcapsules at a rate roughly ten times faster than conventional methods. However, this technique was generally limited to particles above 5 micrometers. For the hydrogel immobilized particles, a naturally derived polysaccharide, agarose, was used as an immobilizing agent. Electrophoresis, convection and diffusion were then used to deposit polymers on immobilized particles and form capsules ranging from below 100 nanometers to above 1 micrometer. These driving forces allow for the use of different polymer combinations, can be used to load various types of cargo, and can be used to form polymer replica particles. Each driving force has unique benefits, and all three driving forces are either already automated, or potentially automatable. The speed, ease, scope and scale with which these capsules can now be

Mussel adhesive proteins are known for their high affinity to a range of different surfaces, and they therefore appear as ideal candidates for producing thin inorganic-organic composite films with high robustness. In this work we explore the possibility of making cohesive films utilizing layer-by-layer deposition of the highly positively charged mussel adhesive protein, Mefp-1, and negatively charged ceria nanoparticles. This particular material combination was chosen due to recent findings that such films provide good corrosion protection. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used for following the film formation process in situ on silica surfaces. A close to linear growth of the film with number of deposited layers was found for up to 18 deposition steps, the highest number of depositions investigated in this work. The Mefp-1 concentration during film deposition affected the film properties, where a higher protein concentration resulted in a stiffer film. It was also found that the added mass could be amplified by using a Mefp-1 solution containing small aggregates. The surface nanomechanical properties of dried multilayer films were investigated using peak force QNM (quantitative nanomechanical mapping) in air. Homogeneous surface coverage was found under all conditions explore, and the Young's modulus of the outer region of the coating increased when a higher Mefp-1 concentration was used during film deposition. The nature of the outermost surface layer was found to significantly affect the surface nanomechanical properties. The abrasion resistance of the coating was measured by using controlled-force contact mode AFM., QC 20130906

The performance of Cs+, C60 + and Ar n + (with n ≈ 1700) sputtering ions have been compared for depth profiling multilayer films made from three evaporated phenylalanine layers sandwiched between four thicker evaporated tyrosine layers. Using Cs +, the ion signals and depth resolution degrade with depth and were significantly affected beyond a 200-nm depth. The depth profiling quality was more successful using C60 +. However, in this case, the depth resolution and the layer width values still degrade with the sputtered depth and are particularly poor after reaching a depth of about 400 nm. When Ar1700 + clusters were used, a depth resolution as low as 6 nm was obtained, and this value never exceeds 9 nm. Moreover, the experimental layer width is found to be of the same order of magnitude as the real value. Copyright © 2012 John Wiley & Sons, Ltd. Copyright © 2012 John Wiley & Sons, Ltd.

Membranes composed of multilayer poly(4-styrenesul- fonate) (PSS)/protonated poly(allylamine) (PAH) fi lms on porous alumina supports exhibit high monovalent/divalent cation selectivities. Remarkably, the di ff usion dialysis K + /Mg 2+ selectivity is >350. However, in nano fi ltration this selectivity is only 16, suggesting some convective ion transport through fi lm imperfections. Under MgCl 2 concentration gradients across either (PSS/PAH) 4 - or (PSS/ PAH) 4 PSS-coated alumina, transmembrane potentials indicate Mg 2+ transference numbers approaching 0. The low Mg 2+ transference numbers with both polycation- and polyanion-terminated fi lms likely stem from exclusion of Mg 2+ due to its large size or hydration energy. However, these high anion/cation selectivities decrease as the solution ionic strength increases. In nano fi ltration, the high asymmetry of membrane permeabilities to Mg 2+ and Cl − creates transmembrane di ff usion potentials that lead to negative rejections (the ion concentration in the permeate is larger than in the feed) as low as − 200% for trace monovalent cations such as K + and Cs + . Moreover, rejection becomes more negative as the mobility of the trace cation increases. Knowledge of single-ion permeabilities is vital for predicting the performance of polyelectrolyte fi lms in the separation and puri fi cation of mixed salts., Peer Reviewed, Postprint (published version)

The present study deals with growth of well-adherent and tough CrN thin films by cylindrical cathodic arc physical vapor deposition. The influence of substrate preparation parameters and deposition variables on film properties has been systematically investigated. The adhesion strength, hardness and crack propagation resistance (CPR) of the films were evaluated for different processing conditions. High substrate hardness and low substrate surface roughness were found to be conducive for obtaining well-adherent films. Cr ion etching was found to yield superior film properties, with the duration of etching also being a key determining factor. The nitrogen partial pressure employed during film deposition was noted to significantly influence the phase combination of the CrN x films as well as the stress levels in the deposited films. In case of multilayer CrN x films, alternating high toughness-low toughness layers were found to yield encouraging properties, with CPR values markedly higher than those obtained in mono-layer CrN x films, with no compromise in either hardness or adhesion strength. © 2012 Elsevier B.V.

Different mechanisms may exists as a means to provide additional or specialized enhancement of existing nanoparticulate pinning in YBa2Cu3O7-x (YBCO) thin films. In the particular case of Y2BaCuO5 (Y211) nanoparticles, Ca-doping of these nanoparticles via addition to the Y211 target material provides an additional increase to the Jc(H). YBCO + Y211 samples were created by pulsed laser deposition with alternating targets of YBCO with Y211 and Y211 doped with Ca. Initial indications suggest that this improvement in pinning results from some scattered short-ranged self-assembly of the nanoparticles into short nanocolumns., Published in Physica C, v469, 2009. Prepared in cooperation with University of Kansas; University of Dayton Research Institute; and UES, Inc. The original document contains color images. All DTIC reproductions will be in black and white.

We report on preparation of redox-active nanoscale layer-by-layer (LbL) films with polyaminoacid-decorated surfaces that serve for both nucleation and growth of uniformly distributed gold nanoparticles at ambient conditions. We found that a poly-L-tyrosine (pTyr), a synthetic polyaminoacid, was able to direct nanoparticle formation to solid, flexible, and patterned surfaces preventing particle agglomeration. The gold particles were 8 +/- 2 nm in diameter, surrounded by 3-6 nm polyaminoacid shell, and confined to the topmost polyaminoacid layer. The reported results on bioinspired gold formation can be readily expanded to any inorganic-selective surface and provide a simple, robust, and nontoxic method to obtain nonaggregated inorganic nanoparticles at ambient conditions., Published in Chemistry of Materials, v20 p5822-5831, 2008. Prepared in collaboration with Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH. Sponsored in part by Office of Naval Research.

We report the use of copolymers synthesized with specific block ratios of weakly and strongly charged groups for the preparation of stable, pH-responsive multilayers. In this study, we utilized reversible addition-fragmentation chain transfer (RAFT) polymerization in the synthesis of novel pH-sensitive copolymers comprising block domains of acrylic acid (AA) and styrene sulfonate (SS) groups. The PAAX-b-SSy copolymers, containing 37%, 55%, and 73% of AA groups by mass (denoted as PAA37-b-SS63, PAA55-b-SS45, and PAA73-b-SS27, respectively), were utilized to perform stepwise multilayer assembly in alternation with poly(allylamine hydrochloride), PAH. The ratio of AA to SS groups, and the effect of the pH of both anionic and cationic adsorption solutions, on multilayer properties, were investigated using ellipsometry and atomic force microscopy. The presence of SS moieties in the PAA X-b-SSy copolymers, regardless of the precise composition, lead to films with a relatively consistent thickness. Exposure of these multilayers to acidic conditions postassembly revealed that these multilayers do not exhibit the characteristic large swelling that occurs with PAA/PAH films. The film stability was attributed to the presence of strongly charged SS groups. PAAx-b-SSy/PAH films were also formed on particle substrates under various adsorption conditions. Microelectrophoresis measurements revealed that the surface charge and isoelectric point of these core-shell particles are dependent on assembly pH and the proportion of AA groups in PAAx-b-SSy. These core-shell particles can be used as precursors to hollow capsules that incorporate weak polyelectrolyte functionality. The role of AA groups in determining the growth profile of these capsules was also examined. The multilayer films prepared may find applications in areas where pH-responsive films are required but large film swelling is unfavorable. © 2008 American Chemical Society.

The superconducting properties of YBa2Cu3O7-x (YBCO or 123) thin films doped with BaZrO3 (BZO) nanoparticles by multilayer and single-target methods were studied and compared. Thin films of 123 + BZO were processed by pulsed laser deposition on LaAlO3 and SrTiO3 single crystal substrates. Multilayer (BZO 0.6 nm - 1.4 nm /23(sub 15) nm)19 structures were grown by alternating deposition from 123 and BZO targets, and BZO additions of 0-2 Vol% were deposited using (1231(sub 1-x) BZO(sub x)) single-targets. The multilayer and single-target methods of BZO addition caused significant differences of superconducting transition temperatures (Tc) measured by AC susceptibility, and critical current densities (Jc) measured by both magnetic and transport methods as a function of temperature (T), applied magnetic field (H) and angle of H field incidence (theta). Single-target films had almost linear decrease of Tc and self-field Jc with BZO vol% addition, and compared to multilayer films had lower Jc(77 K, H 4 T) however had improved high-field properties for Jc(77 K, H 4 T). Multilayer films had almost no decrease of Tc and self-field Jc for high BZO additions up to 10 Vol% and very strong peak of Jc(H ab in - plane) and constant and high Jc(H, 0 80 deg.). Single-target BZO-2 Vol% films had slightly enhanced Jc(H c - axis), consistent with results by other authors., Prepared in collaboration with Los Alamos National Laboratory, Los Alamos, NM, and University of Dayton Research Institute, Dayton, OH. Published in IEEE Transactions on Applied Superconductivity, Vol. 17, No. 2, p3724-3728, June 2007.

The nonlinear optical response arising from a model multilayer structure, i.e., Langmuir-Blodgett (LB) films comprised of different numbers of per-protonated (H) and per-deuterated (D) fatty acid layers on solid substrates, has been evaluated by sum-frequency generation (SFG) spectroscopy. The SFG signals depend significantly on the absolute polar orientation of the fatty acids in the individual layers and on the nonlinear optical response of the substrate. The SFG spectra on gold and fused quartz substrates demonstrate a totally different dependence on the number of the contributing H layers, which it is possible to analyze quantitatively. The results provide important information for understanding the origin of the nonlinear optical responses from ordered systems composed of multiple interfaces and therefore for extracting exact structural information about each interface from the observed SFG signals., QC 20100525

Fabrication strategies based on mechanisms of self-assembly are now widely being recognized as inevitable tools in nanotechnology. Self-organized construction of advanced materials and devices may be done starting with tailor made nanoparticles as building blocks. Multilayer thin films of gold, zinc sulphide and manganese doped zinc Sulfide nanoparticles were fabricated by a modified polyelectrolyte deposition process, A prerequisite to utilization of colloids for the fabrication of uniform layers is that they remain in suspension and resist unwanted agglomeration. The stability of colloids is generally achieved either by electrostatic stabilization, involving the creation of an electrical double layers arising from ions intentionally adsorbed on the surface of the particle and associated counter ions that surround the particle, or by steric hindrance that is achieved by the adsorption of macromolecules on the surface of the particles. The inherent necessity to introduce electrostatic or steric hindrance to avoid colloidal agglomeration was utilized to induce self-assembly of multilayers applying similar concept used for the layering of polyelectrolytes. Polyacrylic acid was used as the polyanion and chitosan as the polycation for the deposition process. Upto 100 layers of nanoparticles were constructed and films that wore found to be stable and uniform over the substrate. The layer-by-layer deposition of multilayers of several different structures was prepared and devices showing resistive and capacitive electrical characteristics have been fabricated. The onset of electrical conduction in the resistive devices could be varied by introducing a dielectric interlayer between gold nanoparticles and by introducing a gold overlayer on the zinc sulphide nanoparticle devices., QC 20160421

A combined experimental and theoretical investigation of advanced nanostructured magnetic materials has been carried out. Novel physical systems have been synthesized and studied including: hard/soft nanocomposites, magnetic nanowires, thermally processed multilayer films, and nanoparticle-assembled composites. Emphasis has been focused on exchange coupling at grain boundaries, incoherent magnetization reversal, and magnetization dynamics. The design of nanomagnets with controlled properties has been emphasized, and unprecedented advances have been made in high-temperature permanent magnets, high-coercivity nanocluster magnets, and hard and soft magnetic nanotubes prepared with chemical methods.

[[abstract]]單層薄膜的功能在應用上已無法滿足需求。根據文獻報導，以多層薄膜或多層奈米薄膜的鍍層可提升母材硬度或韌性優於單層薄膜的性能。 本研究之目的，即利用直流磁控濺鍍法沉積氮化鈦/氮化鉻多層薄膜於SKD11上，探討多層薄膜的微結構及機械性質。除此之外，並探討退火對多層薄膜之微結構及機械性質的影響，而多層薄膜的沉積，以基板溫度為250℃時，其附著性能最好。 磨耗性能分析利用pin-on-disc的方式作往復式磨耗試驗，實驗結果顯示氮化鈦/氮化鉻多層薄膜經500℃退火1小時後，磨耗率較低。當層數為8層的氮化鈦/氮化鉻多層薄膜摩擦係數值約為0.5，而16層的摩擦係數值為0.29。若總膜厚為0.774μm，層數為16層的氮化鈦/氮化鉻多層薄膜，具有較好的抗磨耗性能。, [[abstract]]The function of the single layer film has been already unable to satisfy the demand in using. According to document report, with multilayer films or nano-multilayer films can improve the hardness and the toughness of superior properties to single layer film. The purpose of this paper, is given of the preparation by direct current magnetism sputtering of TiN/CrN multilayer films on SKD11, The microstructure and mechanical properties of multilayer films are discussed. In addition, annealing were also discussed during sputtering and the effects of the microstructure and mechanical properties, Substrate temperature of 250℃, showed a good adhesion strength for TiN/CrN multilayer films. Tribological properties of TiN/CrN multilayer films has been studied using pin-on-disc test procedures. Experimertal results indicate that the wear rate of TiN/CrN multilayer films has a low values after annealing at 500℃for 1 hr. The friction coefficient of 8-layer films was about 0.5, which is slightly higher than that of the 16-layer films about 0.29.The films with a total thicknes about 0.774μm and layer sequence TiN/CrN exhibits good wear resistance on reciprocating wear test.

High-resolution electron microscopy imaging and electron and X-ray diffraction techniques have been used to characterize the structure of low and high flux Au-20%Pd layers in Au-20%Pd/MoS2 multilayer solid lubricant thin films. Images clearly reveal different morphologies for the metal layers in the two flux regimes, which can be correlated to the variation in fracture resistance reported by an earlier indentation study. In the lower metal flux regime, three-dimensional islands with single-crystal and multiply twinned structures are seen, while quasi-continuous, polycrystalline regions are seen in the higher flux case.

Edited trans. of Wuli Xuebao (China) v30 n5 p700-704 May 81.

This paper reports on an irradiation curing method to improve the mechanical, chemical and thermal properties of multilayered flexible materials, to increase the bond strength among the adhesively bonded layers and to provide flexible packages that can withstand the stresses of thermoprocessing and subsequently protect the contents of the packages during normal handling and storage.

Nur-E-Alam, M., Vasiliev, M., Kotov, V.A., Balabanov, D., Akimov, I., Alameh, K. (2015). Properties of exchange coupled all-garnet magneto-optic thin film multilayer structures in Materials, 8(4), 1976-1992. Available here.