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Materials, Volume 8, Issue 11 (November 2015)

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Open AccessArticle TiO2 Nanosols Applied Directly on Textiles Using Different Purification Treatments
Materials 2015, 8(11), 7988-7996; https://doi.org/10.3390/ma8115437
Received: 16 September 2015 / Revised: 28 October 2015 / Accepted: 16 November 2015 / Published: 24 November 2015
Cited by 8 | PDF Full-text (1733 KB) | HTML Full-text | XML Full-text
Abstract
Self-cleaning applications using TiO2 coatings on various supporting media have been attracting increasing interest in recent years. This work discusses the issue of self-cleaning textile production on an industrial scale. A method for producing self-cleaning textiles starting from a commercial colloidal nanosuspension
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Self-cleaning applications using TiO2 coatings on various supporting media have been attracting increasing interest in recent years. This work discusses the issue of self-cleaning textile production on an industrial scale. A method for producing self-cleaning textiles starting from a commercial colloidal nanosuspension (nanosol) of TiO2 is described. Three different treatments were developed for purifying and neutralizing the commercial TiO2 nanosol: washing by ultrafiltration; purifying with an anion exchange resin; and neutralizing in an aqueous solution of ammonium bicarbonate. The different purified TiO2 nanosols were characterized in terms of particle size distribution (using dynamic light scattering), electrical conductivity, and ζ potential (using electrophoretic light scattering). The TiO2-coated textiles’ functional properties were judged on their photodegradation of rhodamine B (RhB), used as a stain model. The photocatalytic performance of the differently treated TiO2-coated textiles was compared, revealing the advantages of purification with an anion exchange resin. The study demonstrated the feasibility of applying commercial TiO2 nanosol directly on textile surfaces, overcoming problems of existing methods that limit the industrial scalability of the process. Full article
(This article belongs to the Special Issue Self-Cleaning and Antimicrobial Surfaces)
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Open AccessArticle Preparation of Cotton-Wool-Like Poly(lactic acid)-Based Composites Consisting of Core-Shell-Type Fibers
Materials 2015, 8(11), 7979-7987; https://doi.org/10.3390/ma8115434
Received: 9 October 2015 / Revised: 10 November 2015 / Accepted: 16 November 2015 / Published: 24 November 2015
Cited by 1 | PDF Full-text (4952 KB) | HTML Full-text | XML Full-text
Abstract
In previous works, we reported the fabrication of cotton-wool-like composites consisting of siloxane-doped vaterite and poly(l-lactic acid) (SiVPCs). Various irregularly shaped bone voids can be filled with the composite, which effectively supplies calcium and silicate ions, enhancing the bone formation by stimulating the
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In previous works, we reported the fabrication of cotton-wool-like composites consisting of siloxane-doped vaterite and poly(l-lactic acid) (SiVPCs). Various irregularly shaped bone voids can be filled with the composite, which effectively supplies calcium and silicate ions, enhancing the bone formation by stimulating the cells. The composites, however, were brittle and showed an initial burst release of ions. In the present work, to improve the mechanical flexibility and ion release, the composite fiber was coated with a soft, thin layer consisting of poly(d,l-lactic-co-glycolic acid) (PLGA). A coaxial electrospinning technique was used to prepare a cotton-wool-like material comprising “core-shell”-type fibers with a diameter of ~12 µm. The fibers, which consisted of SiVPC coated with a ~2-µm-thick PLGA layer, were mechanically flexible; even under a uniaxial compressive load of 1.5 kPa, the cotton-wool-like material did not exhibit fracture of the fibers and, after removing the load, showed a ~60% recovery. In Tris buffer solution, the initial burst release of calcium and silicate ions from the “core-shell”-type fibers was effectively controlled, and the ions were slowly released after one day. Thus, the mechanical flexibility and ion-release behavior of the composites were drastically improved by the thin PLGA coating. Full article
(This article belongs to the Section Advanced Composites)
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Open AccessFeature PaperArticle Growth and Characterization of Lead-free Piezoelectric Single Crystals
Materials 2015, 8(11), 7962-7978; https://doi.org/10.3390/ma8115436
Received: 15 September 2015 / Revised: 30 October 2015 / Accepted: 10 November 2015 / Published: 24 November 2015
Cited by 2 | PDF Full-text (4796 KB) | HTML Full-text | XML Full-text
Abstract
Lead-free piezoelectric materials attract more and more attention owing to the environmental toxicity of lead-containing materials. In this work, we review our first attempts of single crystal grown by the top-seeded solution growth method of BaTiO3 substituted with zirconium and calcium (BCTZ)
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Lead-free piezoelectric materials attract more and more attention owing to the environmental toxicity of lead-containing materials. In this work, we review our first attempts of single crystal grown by the top-seeded solution growth method of BaTiO3 substituted with zirconium and calcium (BCTZ) and (K0.5Na0.5)NbO3 substituted with lithium, tantalum, and antimony (KNLSTN). The growth methodology is optimized in order to reach the best compositions where enhanced properties are expected. Chemical analysis and electrical characterizations are presented for both kinds of crystals. The compositionally-dependent electrical performance is investigated for a better understanding of the relationship between the composition and electrical properties. A cross-over from relaxor to ferroelectric state in BCTZ solid solution is evidenced similar to the one reported in ceramics. In KNLSTN single crystals, we observed a substantial evolution of the orthorhombic-to-tetragonal phase transition under minute composition changes. Full article
(This article belongs to the Special Issue Piezoelectric Materials)
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Open AccessReview Fiber-Embedded Metallic Materials: From Sensing towards Nervous Behavior
Materials 2015, 8(11), 7938-7961; https://doi.org/10.3390/ma8115435
Received: 15 October 2015 / Revised: 8 November 2015 / Accepted: 9 November 2015 / Published: 24 November 2015
Cited by 10 | PDF Full-text (10491 KB) | HTML Full-text | XML Full-text
Abstract
Embedding of fibers in materials has attracted serious attention from researchers and has become a new research trend. Such material structures are usually termed “smart” or more recently “nervous”. Materials can have the capability of sensing and responding to the surrounding environmental stimulus,
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Embedding of fibers in materials has attracted serious attention from researchers and has become a new research trend. Such material structures are usually termed “smart” or more recently “nervous”. Materials can have the capability of sensing and responding to the surrounding environmental stimulus, in the former, and the capability of feeling multiple structural and external stimuli, while feeding information back to a controller for appropriate real-time action, in the latter. In this paper, embeddable fibers, embedding processes, and behavior of fiber-embedded metallic materials are reviewed. Particular emphasis has been given to embedding fiber Bragg grating (FBG) array sensors and piezo wires, because of their high potential to be used in nervous materials for structural health monitoring. Ultrasonic consolidation and laser-based layered manufacturing processes are discussed in detail because of their high potential to integrate fibers without disruption. In addition, current challenges associated with embedding fibers in metallic materials are highlighted and recommendations for future research work are set. Full article
(This article belongs to the Special Issue Bioinspired and Biomimetic Materials)
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Open AccessArticle Compressive Behavior and Microstructural Characteristics of Iron Hollow Sphere Filled Aluminum Matrix Syntactic Foams
Materials 2015, 8(11), 7926-7937; https://doi.org/10.3390/ma8115432
Received: 21 October 2015 / Revised: 14 November 2015 / Accepted: 17 November 2015 / Published: 23 November 2015
Cited by 6 | PDF Full-text (4153 KB) | HTML Full-text | XML Full-text
Abstract
Iron hollow sphere filled aluminum matrix syntactic foams (AMSFs) were produced by low pressure, inert gas assisted infiltration. The microstructure of the produced AMSFs was investigated by light and electron microscopy, extended by energy dispersive X-ray spectroscopy and electron back-scattered diffraction. The investigations
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Iron hollow sphere filled aluminum matrix syntactic foams (AMSFs) were produced by low pressure, inert gas assisted infiltration. The microstructure of the produced AMSFs was investigated by light and electron microscopy, extended by energy dispersive X-ray spectroscopy and electron back-scattered diffraction. The investigations revealed almost perfect infiltration and a slight gradient in the grain size of the matrix. A very thin interface layer that ensures good bonding between the hollow spheres and the matrix was also observed. Compression tests were performed on cylindrical specimens to explore the characteristic mechanical properties of the AMSFs. Compared to other (conventional) metallic foams, the investigated AMSFs proved to have outstanding mechanical properties (yield strength, plateau strength, etc.) and energy absorbing capability. Full article
(This article belongs to the Special Issue Metal Foams: Synthesis, Characterization and Applications)
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Open AccessReview Mechanisms of in Vivo Degradation and Resorption of Calcium Phosphate Based Biomaterials
Materials 2015, 8(11), 7913-7925; https://doi.org/10.3390/ma8115430
Received: 14 October 2015 / Revised: 9 November 2015 / Accepted: 13 November 2015 / Published: 23 November 2015
Cited by 22 | PDF Full-text (2154 KB) | HTML Full-text | XML Full-text
Abstract
Calcium phosphate ceramic materials are extensively used for bone replacement and regeneration in orthopedic, dental, and maxillofacial surgical applications. In order for these biomaterials to work effectively it is imperative that they undergo the process of degradation and resorption in vivo. This
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Calcium phosphate ceramic materials are extensively used for bone replacement and regeneration in orthopedic, dental, and maxillofacial surgical applications. In order for these biomaterials to work effectively it is imperative that they undergo the process of degradation and resorption in vivo. This allows for the space to be created for the new bone tissue to form and infiltrate within the implanted graft material. Several factors affect the biodegradation and resorption of calcium phosphate materials after implantation. Various cell types are involved in the degradation process by phagocytic mechanisms (monocytes/macrophages, fibroblasts, osteoblasts) or via an acidic mechanism to reduce the micro-environmental pH which results in demineralization of the cement matrix and resorption via osteoclasts. These cells exert their degradation effects directly or indirectly through the cytokine growth factor secretion and their sensitivity and response to these biomolecules. This article discusses the mechanisms of calcium phosphate material degradation in vivo. Full article
(This article belongs to the Special Issue Regenerative Materials)
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Open AccessArticle Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes
Materials 2015, 8(11), 7900-7912; https://doi.org/10.3390/ma8115431
Received: 27 August 2015 / Revised: 19 October 2015 / Accepted: 6 November 2015 / Published: 23 November 2015
Cited by 5 | PDF Full-text (3615 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the
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Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. Full article
(This article belongs to the Special Issue Polymer Nanocomposites)
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Open AccessArticle A Direct Electric Field-Aided Biomimetic Mineralization System for Inducing the Remineralization of Dentin Collagen Matrix
Materials 2015, 8(11), 7889-7899; https://doi.org/10.3390/ma8115433
Received: 9 September 2015 / Revised: 25 October 2015 / Accepted: 16 November 2015 / Published: 20 November 2015
Cited by 5 | PDF Full-text (8946 KB) | HTML Full-text | XML Full-text
Abstract
This in vitro study aimed to accelerate the remineralization of a completely demineralized dentine collagen block in order to regenerate the dentinal microstructure of calcified collagen fibrils by a novel electric field-aided biomimetic mineralization system in the absence of non-collagenous proteins. Completely demineralized
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This in vitro study aimed to accelerate the remineralization of a completely demineralized dentine collagen block in order to regenerate the dentinal microstructure of calcified collagen fibrils by a novel electric field-aided biomimetic mineralization system in the absence of non-collagenous proteins. Completely demineralized human dentine slices were prepared using ethylene diamine tetraacetic acid (EDTA) and treated with guanidine hydrochloride to extract the bound non-collagenous proteins. The completely demineralized dentine collagen blocks were then remineralized in a calcium chloride agarose hydrogel and a sodium hydrogen phosphate and fluoride agarose hydrogel. This process was accelerated by subjecting the hydrogels to electrophoresis at 20 mA for 4 and 12 h. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) were used to evaluate the resultant calcification of the dentin collagen matrix. SEM indicated that mineral particles were precipitated on the intertubular dentin collagen matrix; these densely packed crystals mimicked the structure of the original mineralized dentin. However, the dentinal tubules were not occluded by the mineral crystals. XRD and EDX both confirmed that the deposited crystals were fluorinated hydroxyapatite. TEM revealed the existence of intrafibrillar and interfibrillar mineralization of the collagen fibrils. A novel electric field-aided biomimetic mineralization system was successfully developed to remineralize a completely demineralized dentine collagen matrix in the absence of non-collagenous proteins. This study developed an accelerated biomimetic mineralization system which can be a potential protocol for the biomineralization of dentinal defects. Full article
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Open AccessArticle Hydrogenation Properties of TiFe Doped with Zirconium
Materials 2015, 8(11), 7864-7872; https://doi.org/10.3390/ma8115423
Received: 26 August 2015 / Revised: 11 November 2015 / Accepted: 12 November 2015 / Published: 20 November 2015
Cited by 5 | PDF Full-text (6795 KB) | HTML Full-text | XML Full-text
Abstract
The goal of this study was to optimize the activation behaviour of hydrogen storage alloy TiFe. We found that the addition of a small amount of Zr in TiFe alloy greatly reduces the hydrogenation activation time. Two different procedural synthesis methods were applied:
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The goal of this study was to optimize the activation behaviour of hydrogen storage alloy TiFe. We found that the addition of a small amount of Zr in TiFe alloy greatly reduces the hydrogenation activation time. Two different procedural synthesis methods were applied: co-melt, where the TiFe was melted and afterward re-melted with the addition of Zr, and single-melt, where Ti, Fe and Zr were melted together in one single operation. The co-melted sample absorbed hydrogen at its maximum capacity in less than three hours without any pre-treatment. The single-melted alloy absorbed its maximum capacity in less than seven hours, also without pre-treatment. The reason for discrepancies between co-melt and single-melt alloys was found to be the different microstructure. The effect of air exposure was also investigated. We found that the air-exposed samples had the same maximum capacity as the argon protected samples but with a slightly longer incubation time, which is probably due to the presence of a dense surface oxide layer. Scanning electron microscopy revealed the presence of a rich Zr intergranular phase in the TiFe matrix, which is responsible for the enhanced hydrogenation properties of these Zr-doped TiFe alloys. Full article
(This article belongs to the Special Issue Hydrogen Storage Materials)
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Open AccessArticle Characterization of Thermo-Physical Properties of EVA/ATH: Application to Gasification Experiments and Pyrolysis Modeling
Materials 2015, 8(11), 7837-7863; https://doi.org/10.3390/ma8115428
Received: 15 October 2015 / Revised: 6 November 2015 / Accepted: 11 November 2015 / Published: 20 November 2015
Cited by 3 | PDF Full-text (5769 KB) | HTML Full-text | XML Full-text
Abstract
The pyrolysis of solid polymeric materials is a complex process that involves both chemical and physical phenomena such as phase transitions, chemical reactions, heat transfer, and mass transport of gaseous components. For modeling purposes, it is important to characterize and to quantify the
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The pyrolysis of solid polymeric materials is a complex process that involves both chemical and physical phenomena such as phase transitions, chemical reactions, heat transfer, and mass transport of gaseous components. For modeling purposes, it is important to characterize and to quantify the properties driving those phenomena, especially in the case of flame-retarded materials. In this study, protocols have been developed to characterize the thermal conductivity and the heat capacity of an ethylene-vinyl acetate copolymer (EVA) flame retarded with aluminum tri-hydroxide (ATH). These properties were measured for the various species identified across the decomposition of the material. Namely, the thermal conductivity was found to decrease as a function of temperature before decomposition whereas the ceramic residue obtained after the decomposition at the steady state exhibits a thermal conductivity as low as 0.2 W/m/K. The heat capacity of the material was also investigated using both isothermal modulated Differential Scanning Calorimetry (DSC) and the standard method (ASTM E1269). It was shown that the final residue exhibits a similar behavior to alumina, which is consistent with the decomposition pathway of EVA/ATH. Besides, the two experimental approaches give similar results over the whole range of temperatures. Moreover, the optical properties before decomposition and the heat capacity of the decomposition gases were also analyzed. Those properties were then used as input data for a pyrolysis model in order to predict gasification experiments. Mass losses of gasification experiments were well predicted, thus validating the characterization of the thermo-physical properties of the material. Full article
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Open AccessFeature PaperReview Extrinsic Contribution and Instability Properties in Lead-Based and Lead-Free Piezoceramics
Materials 2015, 8(11), 7821-7836; https://doi.org/10.3390/ma8115426
Received: 19 October 2015 / Revised: 11 November 2015 / Accepted: 13 November 2015 / Published: 19 November 2015
Cited by 7 | PDF Full-text (1718 KB) | HTML Full-text | XML Full-text
Abstract
Piezoceramic materials generally exhibit a notable instability of their functional properties when they work under real external conditions. This undesirable effect, known as nonlinear behavior, is mostly associated with the extrinsic contribution to material response. In this article, the role of the ferroelectric
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Piezoceramic materials generally exhibit a notable instability of their functional properties when they work under real external conditions. This undesirable effect, known as nonlinear behavior, is mostly associated with the extrinsic contribution to material response. In this article, the role of the ferroelectric domain walls’ motion in the nonlinear response in the most workable lead-based and lead-free piezoceramics is reviewed. Initially, the extrinsic origin of the nonlinear response is discussed in terms of the temperature dependence of material response. The influence of the crystallographic phase and of the phase boundaries on the material response are then reviewed. Subsequently, the impact of the defects created by doping in order to control the extrinsic contribution is discussed as a way of tuning material properties. Finally, some aspects related to the grain-size effect on the nonlinear response of piezoceramics are surveyed. Full article
(This article belongs to the Special Issue Piezoelectric Materials)
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Open AccessArticle Magnetic Control of Fe3O4 Nanomaterial for Fat Ablation in Microchannel
Materials 2015, 8(11), 7813-7820; https://doi.org/10.3390/ma8115429
Received: 14 October 2015 / Revised: 12 November 2015 / Accepted: 13 November 2015 / Published: 19 November 2015
Cited by 2 | PDF Full-text (3836 KB) | HTML Full-text | XML Full-text
Abstract
In this study, surface modification of iron (II, III) oxide Fe3O4 nanoparticles by oleic acid (OA) coating is investigated for the microablation of fat in a microchannel. The nanoparticles are synthesized by the co-precipitation method and then dispersed in organic
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In this study, surface modification of iron (II, III) oxide Fe3O4 nanoparticles by oleic acid (OA) coating is investigated for the microablation of fat in a microchannel. The nanoparticles are synthesized by the co-precipitation method and then dispersed in organic solvent prior to mixing with the OA. The magnetization, agglomeration, and particle size distribution properties of the OA-coated Fe3O4 nanoparticles are characterized. The surface modification of the Fe3O4 nanoparticles reveals that upon injection into a microchannel, the lipophilicity of the OA coating influences the movement of the nanoparticles across an oil-phase barrier. The motion of the nanoparticles is controlled using an AC magnetic field to induce magnetic torque and a static gradient field to control linear translation. The fat microablation process in a microchannel is demonstrated using an oscillating driving field of less than 1200 Am−1. Full article
(This article belongs to the Special Issue Selected Papers from ICETI2014)
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Open AccessArticle Chiral Nematic Structure of Cellulose Nanocrystal Suspensions and Films; Polarized Light and Atomic Force Microscopy
Materials 2015, 8(11), 7873-7888; https://doi.org/10.3390/ma8115427
Received: 5 October 2015 / Revised: 4 November 2015 / Accepted: 10 November 2015 / Published: 18 November 2015
Cited by 27 | PDF Full-text (9971 KB) | HTML Full-text | XML Full-text
Abstract
Cellulosic liquid crystalline solutions and suspensions form chiral nematic phases that show a rich variety of optical textures in the liquid crystalline state. These ordered structures may be preserved in solid films prepared by evaporation of solvent or suspending medium. Film formation from
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Cellulosic liquid crystalline solutions and suspensions form chiral nematic phases that show a rich variety of optical textures in the liquid crystalline state. These ordered structures may be preserved in solid films prepared by evaporation of solvent or suspending medium. Film formation from aqueous suspensions of cellulose nanocrystals (CNC) was investigated by polarized light microscopy, optical profilometry and atomic force microscopy (AFM). An attempt is made to interpret qualitatively the observed textures in terms of the orientation of the cellulose nanocrystals in the suspensions and films, and the changes in orientation caused by the evaporative process. Mass transfer within the evaporating droplet resulted in the formation of raised rings whose magnitude depended on the degree of pinning of the receding contact line. AFM of dry films at short length scales showed a radial orientation of the CNC at the free surface of the film, along with a radial height variation with a period of approximately P/2, ascribed to the anisotropic shrinkage of the chiral nematic structure. Full article
(This article belongs to the Section Biomaterials)
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Open AccessArticle Inhibition of Crystal Growth during Plasma Enhanced Atomic Layer Deposition by Applying BIAS
Materials 2015, 8(11), 7805-7812; https://doi.org/10.3390/ma8115425
Received: 28 September 2015 / Revised: 9 November 2015 / Accepted: 12 November 2015 / Published: 18 November 2015
Cited by 5 | PDF Full-text (3967 KB) | HTML Full-text | XML Full-text
Abstract
In this study, the influence of direct current (DC) biasing on the growth of titanium dioxide (TiO2) layers and their nucleation behavior has been investigated. Titania films were prepared by plasma enhanced atomic layer deposition (PEALD) using Ti(OiPr)4 as metal
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In this study, the influence of direct current (DC) biasing on the growth of titanium dioxide (TiO2) layers and their nucleation behavior has been investigated. Titania films were prepared by plasma enhanced atomic layer deposition (PEALD) using Ti(OiPr)4 as metal organic precursor. Oxygen plasma, provided by remote inductively coupled plasma, was used as an oxygen source. The TiO2 films were deposited with and without DC biasing. A strong dependence of the applied voltage on the formation of crystallites in the TiO2 layer is shown. These crystallites form spherical hillocks on the surface which causes high surface roughness. By applying a higher voltage than the plasma potential no hillock appears on the surface. Based on these results, it seems likely, that ions are responsible for the nucleation and hillock growth. Hence, the hillock formation can be controlled by controlling the ion energy and ion flux. The growth per cycle remains unchanged, whereas the refractive index slightly decreases in the absence of energetic oxygen ions. Full article
(This article belongs to the Special Issue Atomic Layer Deposition of Functional Materials)
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Open AccessArticle Preparation and Preliminary Dielectric Characterization of Structured C60-Thiol-Ene Polymer Nanocomposites Assembled Using the Thiol-Ene Click Reaction
Materials 2015, 8(11), 7795-7804; https://doi.org/10.3390/ma8115424
Received: 30 September 2015 / Revised: 4 November 2015 / Accepted: 12 November 2015 / Published: 18 November 2015
Cited by 6 | PDF Full-text (1775 KB) | HTML Full-text | XML Full-text
Abstract
Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high
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Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high volume resistivity. A series of structured fullerene (C60) polymer nanocomposites were assembled using the thiol-ene click reaction, between alkyl thiols and allyl functionalized C60 derivatives. The resulting high-density C60-urethane-thiol-ene (C60-Thiol-Ene) networks possessed excellent mechanical properties. These novel networks were characterized using standard techniques, including infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal gravimetric analysis (TGA). The dielectric spectra for the prepared samples were determined over a broad frequency range at room temperature using a broadband dielectric spectrometer and a semiconductor characterization system. The changes in thermo-mechanical and electrical properties of these novel fullerene-thiol-ene composite films were measured as a function of the C60 content, and samples characterized by high dielectric permittivity and low dielectric loss were produced. In this process, variations in chemical composition of the networks were correlated to performance characteristics. Full article
(This article belongs to the Special Issue Polymer Nanocomposites)
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