Materials

266 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Materials in 2015

by Materials Editorial Office

Materials 2016, 9(1), 66; https://doi.org/10.3390/ma9010066 - 21 Jan 2016

Viewed by 5600

The editors of Materials would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2015. [...] Full article

11409 KiB

Open AccessFeature PaperArticle

Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain

by Gerhard Müller, Angelika Hackner, Sebastian Beer and Johann Göbel

Materials 2016, 9(1), 65; https://doi.org/10.3390/ma9010065 - 20 Jan 2016

Cited by 14 | Viewed by 12173

Abstract

The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute [...] Read more.

The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form. Full article

(This article belongs to the Special Issue Nanostructured Materials for Chemical Sensing Applications)

► Show Figures

Figure 1

8616 KiB

Open AccessFeature PaperArticle

Influence of Radiation Sterilization on Properties of Biodegradable Lactide/Glycolide/Trimethylene Carbonate and Lactide/Glycolide/ε-caprolactone Porous Scaffolds with Shape Memory Behavior

by Piotr Rychter, Natalia Śmigiel-Gac, Elżbieta Pamuła, Anna Smola-Dmochowska, Henryk Janeczek, Wojciech Prochwicz and Piotr Dobrzyński

Materials 2016, 9(1), 64; https://doi.org/10.3390/ma9010064 - 20 Jan 2016

Cited by 15 | Viewed by 7570

Abstract

The aim of the study was the evaluation of gamma irradiation and electron beams for sterilization of porous scaffolds with shape memory behavior obtained from biodegradable terpolymers: poly(l-lactide-co-glycolide-co-trimethylene carbonate) and poly(l-lactide-co-glycolide-co-ɛ-caprolactone). [...] Read more.

The aim of the study was the evaluation of gamma irradiation and electron beams for sterilization of porous scaffolds with shape memory behavior obtained from biodegradable terpolymers: poly(l-lactide-co-glycolide-co-trimethylene carbonate) and poly(l-lactide-co-glycolide-co-ɛ-caprolactone). The impact of mentioned sterilization techniques on the structure of the scaffolds before and after the sterilization process using irradiation doses ranged from 10 to 25 kGy has been investigated. Treatment of the samples with gamma irradiation at 15 kGy dose resulted in considerable drop in glass transition temperature (T_g) and number average molecular weight (M_n). For comparison, after irradiation of the samples using an electron beam with the same dose, no significant changes in structure or properties of examined scaffolds have been noticed. Higher doses of irradiation via electron beam caused essential changes of the scaffolds’ pores resulting in partial melting of their surface. Nevertheless, obtained results have revealed that sterilization with electron beam, when compared to gamma irradiation, is a better method because it does not affect significantly the physicochemical properties of the scaffolds. Both used methods of sterilization did not influence the shape memory behavior of the examined materials. Full article

(This article belongs to the Special Issue Biodegradable and Bio-Based Polymers)

► Show Figures

Graphical abstract

2572 KiB

Open AccessArticle

Influence of Oxygen Concentration on the Performance of Ultra-Thin RF Magnetron Sputter Deposited Indium Tin Oxide Films as a Top Electrode for Photovoltaic Devices

by Jephias Gwamuri, Murugesan Marikkannan, Jeyanthinath Mayandi, Patrick K. Bowen and Joshua M. Pearce

Materials 2016, 9(1), 63; https://doi.org/10.3390/ma9010063 - 20 Jan 2016

Cited by 49 | Viewed by 9844

Abstract

The opportunity for substantial efficiency enhancements of thin film hydrogenated amorphous silicon (a-Si:H) solar photovoltaic (PV) cells using plasmonic absorbers requires ultra-thin transparent conducting oxide top electrodes with low resistivity and high transmittances in the visible range of the electromagnetic spectrum. Fabricating ultra-thin [...] Read more.

The opportunity for substantial efficiency enhancements of thin film hydrogenated amorphous silicon (a-Si:H) solar photovoltaic (PV) cells using plasmonic absorbers requires ultra-thin transparent conducting oxide top electrodes with low resistivity and high transmittances in the visible range of the electromagnetic spectrum. Fabricating ultra-thin indium tin oxide (ITO) films (sub-50 nm) using conventional methods has presented a number of challenges; however, a novel method involving chemical shaving of thicker (greater than 80 nm) RF sputter deposited high-quality ITO films has been demonstrated. This study investigates the effect of oxygen concentration on the etch rates of RF sputter deposited ITO films to provide a detailed understanding of the interaction of all critical experimental parameters to help create even thinner layers to allow for more finely tune plasmonic resonances. ITO films were deposited on silicon substrates with a 98-nm, thermally grown oxide using RF magnetron sputtering with oxygen concentrations of 0, 0.4 and 1.0 sccm and annealed at 300 °C air ambient. Then the films were etched using a combination of water and hydrochloric and nitric acids for 1, 3, 5 and 8 min at room temperature. In-between each etching process cycle, the films were characterized by X-ray diffraction, atomic force microscopy, Raman Spectroscopy, 4-point probe (electrical conductivity), and variable angle spectroscopic ellipsometry. All the films were polycrystalline in nature and highly oriented along the (222) reflection. Ultra-thin ITO films with record low resistivity values (as low as 5.83 × 10⁻⁴ Ω·cm) were obtained and high optical transparency is exhibited in the 300–1000 nm wavelength region for all the ITO films. The etch rate, preferred crystal lattice growth plane, d-spacing and lattice distortion were also observed to be highly dependent on the nature of growth environment for RF sputter deposited ITO films. The structural, electrical, and optical properties of the ITO films are discussed with respect to the oxygen ambient nature and etching time in detail to provide guidance for plasmonic enhanced a-Si:H solar PV cell fabrication. Full article

(This article belongs to the Special Issue Photovoltaic Materials and Electronic Devices)

► Show Figures

Figure 1

2319 KiB

Open AccessArticle

Comparison of Cyclic Hysteresis Behavior between Cross-Ply C/SiC and SiC/SiC Ceramic-Matrix Composites

by Longbiao Li

Materials 2016, 9(1), 62; https://doi.org/10.3390/ma9010062 - 19 Jan 2016

Cited by 7 | Viewed by 5016

Abstract

In this paper, the comparison of cyclic hysteresis behavior between cross-ply C/SiC and SiC/SiC ceramic-matrix composites (CMCs) has been investigated. The interface slip between fibers and the matrix existed in the matrix cracking mode 3 and mode 5, in which matrix cracking and [...] Read more.

In this paper, the comparison of cyclic hysteresis behavior between cross-ply C/SiC and SiC/SiC ceramic-matrix composites (CMCs) has been investigated. The interface slip between fibers and the matrix existed in the matrix cracking mode 3 and mode 5, in which matrix cracking and interface debonding occurred in the 0° plies are considered as the major reason for hysteresis loops of cross-ply CMCs. The hysteresis loops of cross-ply C/SiC and SiC/SiC composites corresponding to different peak stresses have been predicted using present analysis. The damage parameter, i.e., the proportion of matrix cracking mode 3 in the entire matrix cracking modes of the composite, and the hysteresis dissipated energy increase with increasing peak stress. The damage parameter and hysteresis dissipated energy of C/SiC composite under low peak stress are higher than that of SiC/SiC composite; However, at high peak stress, the damage extent inside of cross-ply SiC/SiC composite is higher than that of C/SiC composite as more transverse cracks and matrix cracks connect together. Full article

(This article belongs to the Section Advanced Composites)

► Show Figures

Figure 1

4154 KiB

Open AccessArticle

Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition

by Junsheng Liang, Pengfei Li, Dazhi Wang, Xu Fang, Jiahong Ding, Junxiong Wu and Chang Tang

Materials 2016, 9(1), 61; https://doi.org/10.3390/ma9010061 - 19 Jan 2016

Cited by 7 | Viewed by 5865

Abstract

Dense and crack-free barium titanate (BaTiO₃, BTO) thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet) deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. [...] Read more.

Dense and crack-free barium titanate (BaTiO₃, BTO) thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet) deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. Impacts of the jet height and line-to-line pitch of the deposition on the micro-structure of BTO thin films were investigated. Results show that crack-free BTO thin films can be prepared with 4 mm jet height and 300 μm line-to-line pitch in this work. Dielectric constant of the prepared BTO thin film was recorded as high as 2940 at 1 kHz at room temperature. Meanwhile, low dissipation factor of the BTO thin film of about 8.6% at 1 kHz was also obtained. The layer-by-layer E-jet deposition technique developed in this work has been proved to be a cost-effective, flexible and easy to control approach for the preparation of high-quality solid thin film. Full article

► Show Figures

Figure 1

1800 KiB

Open AccessArticle

Parameters Influencing the Growth of ZnO Nanowires as Efficient Low Temperature Flexible Perovskite-Based Solar Cells

by Alex Dymshits, Lior Iagher and Lioz Etgar

Materials 2016, 9(1), 60; https://doi.org/10.3390/ma9010060 - 19 Jan 2016

Cited by 37 | Viewed by 7506

Abstract

Hybrid organic-inorganic perovskite has proved to be a superior material for photovoltaic solar cells. In this work we investigate the parameters influencing the growth of ZnO nanowires (NWs) for use as an efficient low temperature photoanode in perovskite-based solar cells. The structure of [...] Read more.

Hybrid organic-inorganic perovskite has proved to be a superior material for photovoltaic solar cells. In this work we investigate the parameters influencing the growth of ZnO nanowires (NWs) for use as an efficient low temperature photoanode in perovskite-based solar cells. The structure of the solar cell is FTO (SnO₂:F)-glass (or PET-ITO (In₂O₃·(SnO₂) (ITO)) on, polyethylene terephthalate (PET)/ZnAc seed layer/ZnO NWs/CH₃NH₃PbI₃/Spiro-OMeTAD/Au. The influence of the growth rate and the diameter of the ZnO NWs on the photovoltaic performance were carefully studied. The ZnO NWs perovskite-based solar cell demonstrates impressive power conversion efficiency of 9.06% on a rigid substrate with current density over 21 mA/cm². In addition, we successfully fabricated flexible perovskite solar cells while maintaining all fabrication processes at low temperature, achieving power conversion efficiency of 6.4% with excellent stability for over 75 bending cycles. Full article

(This article belongs to the Section Energy Materials)

► Show Figures

Graphical abstract

3827 KiB

Open AccessArticle

Development of Hollow Steel Ball Macro-Encapsulated PCM for Thermal Energy Storage Concrete

by Zhijun Dong, Hongzhi Cui, Waiching Tang, Dazhu Chen and Haibo Wen

Materials 2016, 9(1), 59; https://doi.org/10.3390/ma9010059 - 19 Jan 2016

Cited by 48 | Viewed by 8864

Abstract

The application of thermal energy storage with phase change materials (PCMs) for energy efficiency of buildings grew rapidly in the last few years. In this research, octadecane paraffin was served as a PCM, and a structural concrete with the function of indoor temperature [...] Read more.

The application of thermal energy storage with phase change materials (PCMs) for energy efficiency of buildings grew rapidly in the last few years. In this research, octadecane paraffin was served as a PCM, and a structural concrete with the function of indoor temperature control was developed by using a macro-encapsulated PCM hollow steel ball (HSB). The macro-encapsulated PCM-HSB was prepared by incorporation of octadecane into HSBs through vacuum impregnation. Test results showed that the maximum percentage of octadecane carried by HSBs was 80.3% by mass. The macro-encapsulated PCM-HSB has a latent heat storage capacity as high as 200.5 J/g. The compressive strength of concrete with macro-encapsulated PCM-HSB at 28 days ranged from 22 to 40 MPa. The indoor thermal performance test revealed that concrete with macro-encapsulated octadecane-HSB was capable of reducing the peak indoor air temperature and the fluctuation of indoor temperature. It can be very effective in transferring the heating and cooling loads away from the peak demand times. Full article

(This article belongs to the Special Issue Development and Characterisation of Encapsulated PCM: Nano-, Micro-, and Macro-Encapsulation)

► Show Figures

Figure 1

1664 KiB

Open AccessArticle

The Correlation of Surfactant Concentrations on the Properties of Mesoporous Bioactive Glass

by Shao-Ju Shih, Yu-Chien Lin, Leon Valentino Posma Panjaitan and Dyka Rahayu Meyla Sari

Materials 2016, 9(1), 58; https://doi.org/10.3390/ma9010058 - 19 Jan 2016

Cited by 24 | Viewed by 5465

Abstract

Bioactive glass (BG), a potential biomaterial, has received increasing attention since the discovery of its superior bioactivity. One of the main research objectives is to improve the bioactive property of BGs; therefore, surfactant-derived mesoporous bioactive glasses (MBGs) were developed to provide a high [...] Read more.

Bioactive glass (BG), a potential biomaterial, has received increasing attention since the discovery of its superior bioactivity. One of the main research objectives is to improve the bioactive property of BGs; therefore, surfactant-derived mesoporous bioactive glasses (MBGs) were developed to provide a high specific surface area for achieving higher bioactivity. In this study, various concentrations of typical triblock F127 surfactant were used to manipulate the morphology, specific surface area, and bioactivity of MBG particles. Two typical morphologies of smooth (Type I) and wrinkled (Type II) spheres were observed, and the population of Type II particles increased with an increase in the surfactant concentration. A direct correlation between specific surface area and bioactivity was observed by comparing the data obtained using the nitrogen adsorption-desorption method and in vitro bioactive tests. Furthermore, the optimal surfactant concentration corresponding to the highest bioactivity revealed that the surfactant aggregated to form Type II particles when the surface concentration was higher than the critical micelle concentration, and the high population of Type II particles may reduce the specific surface area because of the loss of bioactivity. Moreover, the formation mechanism of SP-derived MBG particles is discussed. Full article

(This article belongs to the Special Issue Bioactive Glasses)

► Show Figures

Figure 1

3587 KiB

Open AccessReview

Advanced Engineering Strategies for Periodontal Complex Regeneration

by Chan Ho Park, Kyoung-Hwa Kim, Yong-Moo Lee and Yang-Jo Seol

Materials 2016, 9(1), 57; https://doi.org/10.3390/ma9010057 - 18 Jan 2016

Cited by 40 | Viewed by 8343

Abstract

The regeneration and integration of multiple tissue types is critical for efforts to restore the function of musculoskeletal complex. In particular, the neogenesis of periodontal constructs for systematic tooth-supporting functions is a current challenge due to micron-scaled tissue compartmentalization, oblique/perpendicular orientations of fibrous [...] Read more.

The regeneration and integration of multiple tissue types is critical for efforts to restore the function of musculoskeletal complex. In particular, the neogenesis of periodontal constructs for systematic tooth-supporting functions is a current challenge due to micron-scaled tissue compartmentalization, oblique/perpendicular orientations of fibrous connective tissues to the tooth root surface and the orchestration of multiple regenerated tissues. Although there have been various biological and biochemical achievements, periodontal tissue regeneration remains limited and unpredictable. The purpose of this paper is to discuss current advanced engineering approaches for periodontal complex formations; computer-designed, customized scaffolding architectures; cell sheet technology-based multi-phasic approaches; and patient-specific constructs using bioresorbable polymeric material and 3-D printing technology for clinical application. The review covers various advanced technologies for periodontal complex regeneration and state-of-the-art therapeutic avenues in periodontal tissue engineering. Full article

(This article belongs to the Special Issue Regenerative Materials)

► Show Figures

Figure 1

16898 KiB

Open AccessArticle

Thermo-Mechanical Compatibility of Viscoelastic Mortars for Stone Repair

by Thibault Demoulin, George W. Scherer, Fred Girardet and Robert J. Flatt

Materials 2016, 9(1), 56; https://doi.org/10.3390/ma9010056 - 18 Jan 2016

Cited by 2 | Viewed by 5654

Abstract

The magnitude of the thermal stresses that originate in an acrylic-based repair material used for the reprofiling of natural sandstone is analyzed. This kind of artificial stone was developed in the late 1970s for its peculiar property of reversibility in an organic solvent. [...] Read more.

The magnitude of the thermal stresses that originate in an acrylic-based repair material used for the reprofiling of natural sandstone is analyzed. This kind of artificial stone was developed in the late 1970s for its peculiar property of reversibility in an organic solvent. However, it displays a high thermal expansion coefficient, which can be a matter of concern for the durability either of the repair or of the underlying original stone. To evaluate this risk we propose an analytical solution that considers the viscoelasticity of the repair layer. The temperature profile used in the numerical evaluation has been measured in a church where artificial stone has been used in a recent restoration campaign. The viscoelasticity of the artificial stone has been characterized by stress relaxation experiments. The numerical analysis shows that the relaxation time of the repair mortar, originating from a low T g , allows relief of most of the thermal stresses. It explains the good durability of this particular repair material, as observed by the practitioners, and provides a solid scientific basis for considering that the problem of thermal expansion mismatch is not an issue for this type of stone under any possible conditions of natural exposure. Full article

► Show Figures

Graphical abstract

1590 KiB

Open AccessArticle

Theoretical and Experimental Studies on the Crystal Structure, Electronic Structure and Optical Properties of SmTaO₄

by Song Wang, Miao Jiang, Lihong Gao, Zhuang Ma and Fuchi Wang

Materials 2016, 9(1), 55; https://doi.org/10.3390/ma9010055 - 18 Jan 2016

Cited by 22 | Viewed by 5996

Abstract

The crystal structure, electronic structure and optical properties of SmTaO₄ were identified through an experimental method and first principles calculation. X-ray powder diffraction (XRD) and a spectrophotometer were used to characterize the crystal structure, reflectivity and band gap of this material; furthermore, [...] Read more.

The crystal structure, electronic structure and optical properties of SmTaO₄ were identified through an experimental method and first principles calculation. X-ray powder diffraction (XRD) and a spectrophotometer were used to characterize the crystal structure, reflectivity and band gap of this material; furthermore, the electronic structure and optical properties were investigated according to three exchange-correlation potentials, LDA, GGA and GGA + U. Results show that the SmTaO₄ calcined at 1400 °C with the solid-state reaction method is in monoclinic phase in the space group I²/a. In addition, the calculated lattice parameters are consistent with the experimental values. The electron transitions among the O 2p states, Sm 4f states and Ta 5d states play a key role in the dielectric function, refractive index, absorption coefficient and reflectivity of SmTaO₄. The calculation of first principles provides considerable insight into the relationship between the electronic structure and optical properties of this material. Full article

► Show Figures

Figure 1

7539 KiB

Open AccessArticle

Tuning the Performance of Metallic Auxetic Metamaterials by Using Buckling and Plasticity

by Arash Ghaedizadeh, Jianhu Shen, Xin Ren and Yi Min Xie

Materials 2016, 9(1), 54; https://doi.org/10.3390/ma9010054 - 18 Jan 2016

Cited by 71 | Viewed by 13090

Abstract

Metallic auxetic metamaterials are of great potential to be used in many applications because of their superior mechanical performance to elastomer-based auxetic materials. Due to the limited knowledge on this new type of materials under large plastic deformation, the implementation of such materials [...] Read more.

Metallic auxetic metamaterials are of great potential to be used in many applications because of their superior mechanical performance to elastomer-based auxetic materials. Due to the limited knowledge on this new type of materials under large plastic deformation, the implementation of such materials in practical applications remains elusive. In contrast to the elastomer-based metamaterials, metallic ones possess new features as a result of the nonlinear deformation of their metallic microstructures under large deformation. The loss of auxetic behavior in metallic metamaterials led us to carry out a numerical and experimental study to investigate the mechanism of the observed phenomenon. A general approach was proposed to tune the performance of auxetic metallic metamaterials undergoing large plastic deformation using buckling behavior and the plasticity of base material. Both experiments and finite element simulations were used to verify the effectiveness of the developed approach. By employing this approach, a 2D auxetic metamaterial was derived from a regular square lattice. Then, by altering the initial geometry of microstructure with the desired buckling pattern, the metallic metamaterials exhibit auxetic behavior with tuneable mechanical properties. A systematic parametric study using the validated finite element models was conducted to reveal the novel features of metallic auxetic metamaterials undergoing large plastic deformation. The results of this study provide a useful guideline for the design of 2D metallic auxetic metamaterials for various applications. Full article

(This article belongs to the Special Issue Cellular Materials: Design and Optimisation)

► Show Figures

Graphical abstract

4078 KiB

Open AccessFeature PaperReview

Bottom-Up Synthesis and Sensor Applications of Biomimetic Nanostructures

by Li Wang, Yujing Sun, Zhuang Li, Aiguo Wu and Gang Wei

Materials 2016, 9(1), 53; https://doi.org/10.3390/ma9010053 - 18 Jan 2016

Cited by 57 | Viewed by 10538

Abstract

The combination of nanotechnology, biology, and bioengineering greatly improved the developments of nanomaterials with unique functions and properties. Biomolecules as the nanoscale building blocks play very important roles for the final formation of functional nanostructures. Many kinds of novel nanostructures have been created [...] Read more.

The combination of nanotechnology, biology, and bioengineering greatly improved the developments of nanomaterials with unique functions and properties. Biomolecules as the nanoscale building blocks play very important roles for the final formation of functional nanostructures. Many kinds of novel nanostructures have been created by using the bioinspired self-assembly and subsequent binding with various nanoparticles. In this review, we summarized the studies on the fabrications and sensor applications of biomimetic nanostructures. The strategies for creating different bottom-up nanostructures by using biomolecules like DNA, protein, peptide, and virus, as well as microorganisms like bacteria and plant leaf are introduced. In addition, the potential applications of the synthesized biomimetic nanostructures for colorimetry, fluorescence, surface plasmon resonance, surface-enhanced Raman scattering, electrical resistance, electrochemistry, and quartz crystal microbalance sensors are presented. This review will promote the understanding of relationships between biomolecules/microorganisms and functional nanomaterials in one way, and in another way it will guide the design and synthesis of biomimetic nanomaterials with unique properties in the future. Full article

(This article belongs to the Section Biomaterials)

► Show Figures

Figure 1

9402 KiB

Open AccessFeature PaperReview

Stimuli-Responsive Polymer-Clay Nanocomposites under Electric Fields

by Shang Hao Piao, Seung Hyuk Kwon and Hyoung Jin Choi

Materials 2016, 9(1), 52; https://doi.org/10.3390/ma9010052 - 15 Jan 2016

Cited by 9 | Viewed by 6924

Abstract

This short Feature Article reviews electric stimuli-responsive polymer/clay nanocomposites with respect to their fabrication, physical characteristics and electrorheological (ER) behaviors under applied electric fields when dispersed in oil. Their structural characteristics, morphological features and thermal degradation behavior were examined by X-ray diffraction pattern, [...] Read more.

This short Feature Article reviews electric stimuli-responsive polymer/clay nanocomposites with respect to their fabrication, physical characteristics and electrorheological (ER) behaviors under applied electric fields when dispersed in oil. Their structural characteristics, morphological features and thermal degradation behavior were examined by X-ray diffraction pattern, scanning electron microscopy and transmission electron microscopy, and thermogravimetric analysis, respectively. Particular focus is given to the electro-responsive ER characteristics of the polymer/clay nanocomposites in terms of the yield stress and viscoelastic properties along with their applications. Full article

(This article belongs to the Special Issue Polymer Nanocomposites)

► Show Figures

Figure 1

1529 KiB

Open AccessArticle

Acoustic Behavior of Subfloor Lightweight Mortars Containing Micronized Poly (Ethylene Vinyl Acetate) (EVA)

by Luiza R. Brancher, Maria Fernanda de O. Nunes, Ana Maria C. Grisa, Daniel T. Pagnussat and Mára Zeni

Materials 2016, 9(1), 51; https://doi.org/10.3390/ma9010051 - 15 Jan 2016

Cited by 11 | Viewed by 6346

Abstract

This paper aims to contribute to acoustical comfort in buildings by presenting a study about the polymer waste micronized poly (ethylene vinyl acetate) (EVA) to be used in mortars for impact sound insulation in subfloor systems. The evaluation method included physical, mechanical and [...] Read more.

This paper aims to contribute to acoustical comfort in buildings by presenting a study about the polymer waste micronized poly (ethylene vinyl acetate) (EVA) to be used in mortars for impact sound insulation in subfloor systems. The evaluation method included physical, mechanical and morphological properties of the mortar developed with three distinct thicknesses designs (3, 5, and 7 cm) with replacement percentage of the natural aggregate by 10%, 25%, and 50% EVA. Microscopy analysis showed the surface deposition of cement on EVA, with preservation of polymer porosity. The compressive creep test estimated long-term deformation, where the 10% EVA sample with a 7 cm thick mortar showed the lowest percentage deformation of its height. The impact noise test was performed with 50% EVA samples, reaching an impact sound insulation of 23 dB when the uncovered slab was compared with the 7 cm thick subfloor mortar. Polymer waste addition decreased the mortar compressive strength, and EVA displayed characteristics of an influential material to intensify other features of the composite. Full article

(This article belongs to the Special Issue Utilisation of By-Product Materials in Concrete)

► Show Figures

Figure 1

3600 KiB

Open AccessFeature PaperArticle

Biodegradable Nanocomposite Films Based on Sodium Alginate and Cellulose Nanofibrils

by B. Deepa, Eldho Abraham, Laly A. Pothan, Nereida Cordeiro, Marisa Faria and Sabu Thomas

Materials 2016, 9(1), 50; https://doi.org/10.3390/ma9010050 - 14 Jan 2016

Cited by 156 | Viewed by 12091

Abstract

Biodegradable nanocomposite films were prepared by incorporation of cellulose nanofibrils (CNF) into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt %) on mechanical, biodegradability and swelling behavior of the nanocomposite films were [...] Read more.

Biodegradable nanocomposite films were prepared by incorporation of cellulose nanofibrils (CNF) into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt %) on mechanical, biodegradability and swelling behavior of the nanocomposite films were determined. The results showed that the tensile modulus value of the nanocomposite films increased from 308 to 1403 MPa with increasing CNF content from 0% to 10%; however, it decreased with further increase of the filler content. Incorporation of CNF also significantly reduced the swelling percentage and water solubility of alginate-based films, with the lower values found for 10 wt % in CNF. Biodegradation studies of the films in soil confirmed that the biodegradation time of alginate/CNF films greatly depends on the CNF content. The results evidence that the stronger intermolecular interaction and molecular compatibility between alginate and CNF components was at 10 wt % in CNF alginate films. Full article

(This article belongs to the Special Issue Green Composites)

► Show Figures

Figure 1

4332 KiB

Open AccessArticle

Preparation of Extracellular Matrix Developed Using Porcine Articular Cartilage and In Vitro Feasibility Study of Porcine Articular Cartilage as an Anti-Adhesive Film

by Ji Hye Baek, Kyungsook Kim, Soon Sim Yang, Seung Hun Park, Bo Ram Song, Hee-Woong Yun, Sung In Jeong, Young Jick Kim, Byoung Hyun Min and Moon Suk Kim

Materials 2016, 9(1), 49; https://doi.org/10.3390/ma9010049 - 14 Jan 2016

Cited by 10 | Viewed by 6079

Abstract

In this study, we examined whether porcine articular cartilage (PAC) is a suitable and effective anti-adhesive material. PAC, which contained no non-collagenous tissue components, was collected by mechanical manipulation and decellularization of porcine knee cartilage. The PAC film for use as an anti-adhesive [...] Read more.

In this study, we examined whether porcine articular cartilage (PAC) is a suitable and effective anti-adhesive material. PAC, which contained no non-collagenous tissue components, was collected by mechanical manipulation and decellularization of porcine knee cartilage. The PAC film for use as an anti-adhesive barrier was easily shaped into various sizes using homemade silicone molds. The PAC film was cross-linked to study the usefulness of the anti-adhesive barrier shape. The cross-linked PAC (Cx-PAC) film showed more stable physical properties over extended periods compared to uncross-linked PAC (UnCx-PAC) film. To control the mechanical properties, Cx-PAC film was thermally treated at 45 °C or 65 °C followed by incubation at room temperature. The Cx-PAC films exhibited varying enthalpies, ultimate tensile strength values, and contact angles before and after thermal treatment and after incubation at room temperature. Next, to examine the anti-adhesive properties, human umbilical vein endothelial cells (HUVECs) were cultured on Cx-PAC and thermal-treated Cx-PAC films. Scanning electron microscopy, fluorescence, and MTT assays showed that HUVECs were well adhered to the surface of the plate and proliferated, indicating no inhibition of the attachment and proliferation of HUVECs. In contrast, Cx-PAC and thermal-treated Cx-PAC exhibited little and/or no cell attachment and proliferation because of the inhibition effect on HUVECs. In conclusion, we successfully developed a Cx-PAC film with controllable mechanical properties that can be used as an anti-adhesive barrier. Full article

(This article belongs to the Special Issue Anti-Infective Materials in Medicine and Technology)

► Show Figures

Figure 1

1424 KiB

Open AccessArticle

Synthesis, X-ray Structure, Optical, and Electrochemical Properties of a White-Light-Emitting Molecule

by Jiun-Wei Hu, Ying-Hsuan Wu, Hsing-Yang Tsai and Kew-Yu Chen

Materials 2016, 9(1), 48; https://doi.org/10.3390/ma9010048 - 14 Jan 2016

Cited by 6 | Viewed by 5996

Abstract

A new white-light-emitting molecule (1) was synthesized and characterized by NMR spectroscopy, high resolution mass spectrometry, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pnma, with a = 12.6814(6), b = 7.0824(4), c = 17.4628(9) Å, [...] Read more.

A new white-light-emitting molecule (1) was synthesized and characterized by NMR spectroscopy, high resolution mass spectrometry, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pnma, with a = 12.6814(6), b = 7.0824(4), c = 17.4628(9) Å, α = 90°, β = 90°, γ = 90°. In the crystal, molecules are linked by weak intermolecular C-H···O hydrogen bonds, forming an infinite chain along [100], generating a C(10) motif. Compound 1 possesses an intramolecular six-membered-ring hydrogen bond, from which excited-state intramolecular proton transfer (ESIPT) takes place from the phenolic proton to the carbonyl oxygen, resulting in a tautomer that is in equilibrium with the normal species, exhibiting a dual emission that covers almost all of the visible spectrum and consequently generates white light. It exhibits one irreversible one-electron oxidation and two irreversible one-electron reductions in dichloromethane at modest potentials. Furthermore, the geometric structures, frontier molecular orbitals (MOs), and the potential energy curves (PECs) for 1 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT) and time-dependent DFT calculations. The results demonstrate that the forward and backward ESIPT may happen on a similar timescale, enabling the excited-state equilibrium to be established. Full article

(This article belongs to the Special Issue Materials for Display Applications)

► Show Figures

Graphical abstract

1258 KiB

Open AccessArticle

Surface Functional Poly(lactic Acid) Electrospun Nanofibers for Biosensor Applications

by Edurne González, Larissa M. Shepherd, Laura Saunders and Margaret W. Frey

Materials 2016, 9(1), 47; https://doi.org/10.3390/ma9010047 - 14 Jan 2016

Cited by 50 | Viewed by 8116

Abstract

In this work, biotin surface functionalized hydrophilic non-water-soluble biocompatible poly(lactic acid) (PLA) nanofibers are created for their potential use as biosensors. Varying concentrations of biotin (up to 18 weight total percent (wt %)) were incorporated into PLA fibers together with poly(lactic acid)-block-poly(ethylene glycol) [...] Read more.

In this work, biotin surface functionalized hydrophilic non-water-soluble biocompatible poly(lactic acid) (PLA) nanofibers are created for their potential use as biosensors. Varying concentrations of biotin (up to 18 weight total percent (wt %)) were incorporated into PLA fibers together with poly(lactic acid)-block-poly(ethylene glycol) (PLA-b-PEG) block polymers. While biotin provided surface functionalization, PLA-b-PEG provided hydrophilicity to the final fibers. Morphology and surface-available biotin of the final fibers were studied by Field Emission Scanning Electron Microscopy (FESEM) and competitive colorimetric assays. The incorporation of PLA-b-PEG block copolymers not only decreased fiber diameters but also dramatically increased the amount of biotin available at the fiber surface able to bind avidin. Finally, fiber water stability tests revealed that both biotin and PLA-b-PEG, migrated to the aqueous phase after relatively extended periods of water exposure. The functional hydrophilic nanofiber created in this work shows a potential application as a biosensor for point-of-care diagnostics. Full article

(This article belongs to the Special Issue Electrospun Materials)

► Show Figures

Graphical abstract

2098 KiB

Open AccessLetter

Effects of the F₄TCNQ-Doped Pentacene Interlayers on Performance Improvement of Top-Contact Pentacene-Based Organic Thin-Film Transistors

by Ching-Lin Fan, Wei-Chun Lin, Hsiang-Sheng Chang, Yu-Zuo Lin and Bohr-Ran Huang

Materials 2016, 9(1), 46; https://doi.org/10.3390/ma9010046 - 13 Jan 2016

Cited by 12 | Viewed by 7954

Abstract

In this paper, the top-contact (TC) pentacene-based organic thin-film transistor (OTFT) with a tetrafluorotetracyanoquinodimethane (F₄TCNQ)-doped pentacene interlayer between the source/drain electrodes and the pentacene channel layer were fabricated using the co-evaporation method. Compared with a pentacene-based OTFT without an interlayer, OTFTs [...] Read more.

In this paper, the top-contact (TC) pentacene-based organic thin-film transistor (OTFT) with a tetrafluorotetracyanoquinodimethane (F₄TCNQ)-doped pentacene interlayer between the source/drain electrodes and the pentacene channel layer were fabricated using the co-evaporation method. Compared with a pentacene-based OTFT without an interlayer, OTFTs with an F₄TCNQ:pentacene ratio of 1:1 showed considerably improved electrical characteristics. In addition, the dependence of the OTFT performance on the thickness of the F₄TCNQ-doped pentacene interlayer is weaker than that on a Teflon interlayer. Therefore, a molecular doping-type F₄TCNQ-doped pentacene interlayer is a suitable carrier injection layer that can improve the TC-OTFT performance and facilitate obtaining a stable process window. Full article

(This article belongs to the Special Issue Electrode Materials)

► Show Figures

Figure 1

3281 KiB

Open AccessArticle

Effect of Rare Earth Metals on the Microstructure of Al-Si Based Alloys

by Saleh A. Alkahtani, Emad M. Elgallad, Mahmoud M. Tash, Agnes M. Samuel and Fawzy H. Samuel

Materials 2016, 9(1), 45; https://doi.org/10.3390/ma9010045 - 13 Jan 2016

Cited by 50 | Viewed by 9531

Abstract

The present study was performed on A356 alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the alloy melting [...] Read more.

The present study was performed on A356 alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the alloy melting temperature with no marked change in the temperature of Al-Si eutectic precipitation. Additionally, rare earth metals have no modification effect up to 1.5 wt %. In addition, La and Ce tend to react with Sr leading to modification degradation. In order to achieve noticeable modification of eutectic Si particles, the concentration of rare earth metals should exceed 1.5 wt %, which simultaneously results in the precipitation of a fairly large volume fraction of insoluble intermetallics. The precipitation of these complex intermetallics is expected to have a negative effect on the alloy performance. Full article

(This article belongs to the Special Issue Failure Analysis in Materials)

► Show Figures

Figure 1

9750 KiB

Open AccessFeature PaperArticle

Correlation of High Magnetoelectric Coupling with Oxygen Vacancy Superstructure in Epitaxial Multiferroic BaTiO₃-BiFeO₃ Composite Thin Films

by Michael Lorenz, Gerald Wagner, Vera Lazenka, Peter Schwinkendorf, Michael Bonholzer, Margriet J. Van Bael, André Vantomme, Kristiaan Temst, Oliver Oeckler and Marius Grundmann

Materials 2016, 9(1), 44; https://doi.org/10.3390/ma9010044 - 13 Jan 2016

Cited by 16 | Viewed by 8679

Abstract

Epitaxial multiferroic BaTiO₃-BiFeO₃ composite thin films exhibit a correlation between the magnetoelectric (ME) voltage coefficient α_ME and the oxygen partial pressure during growth. The ME coefficient α_ME reaches high values up to 43 V/(cm·Oe) at 300 K and [...] Read more.

Epitaxial multiferroic BaTiO₃-BiFeO₃ composite thin films exhibit a correlation between the magnetoelectric (ME) voltage coefficient α_ME and the oxygen partial pressure during growth. The ME coefficient α_ME reaches high values up to 43 V/(cm·Oe) at 300 K and at 0.25 mbar oxygen growth pressure. The temperature dependence of α_ME of the composite films is opposite that of recently-reported BaTiO₃-BiFeO₃ superlattices, indicating that strain-mediated ME coupling alone cannot explain its origin. Probably, charge-mediated ME coupling may play a role in the composite films. Furthermore, the chemically-homogeneous composite films show an oxygen vacancy superstructure, which arises from vacancy ordering on the {111} planes of the pseudocubic BaTiO₃-type structure. This work contributes to the understanding of magnetoelectric coupling as a complex and sensitive interplay of chemical, structural and geometrical issues of the BaTiO₃-BiFeO₃ composite system and, thus, paves the way to practical exploitation of magnetoelectric composites. Full article

(This article belongs to the Special Issue Epitaxial Materials 2015)

► Show Figures

Graphical abstract

5064 KiB

Open AccessArticle

Thickness Influence on In Vitro Biocompatibility of Titanium Nitride Thin Films Synthesized by Pulsed Laser Deposition

by Liviu Duta, George E. Stan, Adrian C. Popa, Marius A. Husanu, Sorin Moga, Marcela Socol, Irina Zgura, Florin Miculescu, Iuliana Urzica, Andrei C. Popescu and Ion N. Mihailescu

Materials 2016, 9(1), 38; https://doi.org/10.3390/ma9010038 - 13 Jan 2016

Cited by 28 | Viewed by 8069

Abstract

We report a study on the biocompatibility vs. thickness in the case of titanium nitride (TiN) films synthesized on 410 medical grade stainless steel substrates by pulsed laser deposition. The films were grown in a nitrogen atmosphere, and their in vitro cytotoxicity was [...] Read more.

We report a study on the biocompatibility vs. thickness in the case of titanium nitride (TiN) films synthesized on 410 medical grade stainless steel substrates by pulsed laser deposition. The films were grown in a nitrogen atmosphere, and their in vitro cytotoxicity was assessed according to ISO 10993-5 [1]. Extensive physical-chemical analyses have been carried out on the deposited structures with various thicknesses in order to explain the differences in biological behavior: profilometry, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction and surface energy measurements. XPS revealed the presence of titanium oxynitride beside TiN in amounts that vary with the film thickness. The cytocompatibility of films seems to be influenced by their TiN surface content. The thinner films seem to be more suitable for medical applications, due to the combined high values of bonding strength and superior cytocompatibility. Full article

► Show Figures

Graphical abstract

1032 KiB

Open AccessArticle

Influence of Different Post-Plasma Treatment Storage Conditions on the Shear Bond Strength of Veneering Porcelain to Zirconia

by Mun-Hwan Lee, Bong Ki Min, Jun Sik Son and Tae-Yub Kwon

Materials 2016, 9(1), 43; https://doi.org/10.3390/ma9010043 - 12 Jan 2016

Cited by 32 | Viewed by 5935

Abstract

This in vitro study investigated whether different storage conditions of plasma-treated zirconia specimens affect the shear bond strength of veneering porcelain. Zirconia plates were treated with a non-thermal atmospheric argon plasma (200 W, 600 s). Porcelain veneering (2.38 mm in diameter) was performed [...] Read more.

This in vitro study investigated whether different storage conditions of plasma-treated zirconia specimens affect the shear bond strength of veneering porcelain. Zirconia plates were treated with a non-thermal atmospheric argon plasma (200 W, 600 s). Porcelain veneering (2.38 mm in diameter) was performed immediately (P-I) or after 24 h storage in water (P-W) or air (P-A) on the treated surfaces (n = 10). Untreated plates were used as the control. Each group was further divided into two subgroups according to the application of a ceramic liner. All veneered specimens underwent a shear bond strength (SBS) test. In the X-ray photoelectron spectroscopy (XPS) analysis, the oxygen/carbon ratios of the plasma-treated groups increased in comparison with those of the control group. When a liner was not used, the three plasma-treated groups showed significantly higher SBS values than the control group (p < 0.001), although group P-A exhibited a significantly lower value than the other two groups (p < 0.05). The liner application negatively affected bonding in groups P-I and P-W (p < 0.05). When the veneering step was delayed after plasma treatment of zirconia, storage of the specimens in water was effective in maintaining the cleaned surfaces for optimal bonding with the veneering porcelain. Full article

► Show Figures

Graphical abstract

5524 KiB

Open AccessArticle

Improved Sectional Image Analysis Technique for Evaluating Fiber Orientations in Fiber-Reinforced Cement-Based Materials

by Bang Yeon Lee, Su-Tae Kang, Hae-Bum Yun and Yun Yong Kim

Materials 2016, 9(1), 42; https://doi.org/10.3390/ma9010042 - 12 Jan 2016

Cited by 14 | Viewed by 5693

Abstract

The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fiber-reinforced concrete. A series [...] Read more.

The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fiber-reinforced concrete. A series of tests on the accuracy of fiber detection and the estimation performance of fiber orientation was performed on artificial fiber images to assess the validity of the proposed technique. The validation test results showed that the proposed technique estimates the distribution of fiber orientation more accurately than the direct measurement of fiber orientation by image analysis. Full article

(This article belongs to the Special Issue Image Analysis and Processing for Cement-based Materials)

► Show Figures

Figure 1

4276 KiB

Open AccessReview

Failure Analysis in Magnetic Tunnel Junction Nanopillar with Interfacial Perpendicular Magnetic Anisotropy

by Weisheng Zhao, Xiaoxuan Zhao, Boyu Zhang, Kaihua Cao, Lezhi Wang, Wang Kang, Qian Shi, Mengxing Wang, Yu Zhang, You Wang, Shouzhong Peng, Jacques-Olivier Klein, Lirida Alves De Barros Naviner and Dafine Ravelosona

Materials 2016, 9(1), 41; https://doi.org/10.3390/ma9010041 - 12 Jan 2016

Cited by 74 | Viewed by 14742

Abstract

Magnetic tunnel junction nanopillar with interfacial perpendicular magnetic anisotropy (PMA-MTJ) becomes a promising candidate to build up spin transfer torque magnetic random access memory (STT-MRAM) for the next generation of non-volatile memory as it features low spin transfer switching current, fast speed, high [...] Read more.

Magnetic tunnel junction nanopillar with interfacial perpendicular magnetic anisotropy (PMA-MTJ) becomes a promising candidate to build up spin transfer torque magnetic random access memory (STT-MRAM) for the next generation of non-volatile memory as it features low spin transfer switching current, fast speed, high scalability, and easy integration into conventional complementary metal oxide semiconductor (CMOS) circuits. However, this device suffers from a number of failure issues, such as large process variation and tunneling barrier breakdown. The large process variation is an intrinsic issue for PMA-MTJ as it is based on the interfacial effects between ultra-thin films with few layers of atoms; the tunneling barrier breakdown is due to the requirement of an ultra-thin tunneling barrier (e.g., <1 nm) to reduce the resistance area for the spin transfer torque switching in the nanopillar. These failure issues limit the research and development of STT-MRAM to widely achieve commercial products. In this paper, we give a full analysis of failure mechanisms for PMA-MTJ and present some eventual solutions from device fabrication to system level integration to optimize the failure issues. Full article

► Show Figures

Figure 1

7771 KiB

Open AccessFeature PaperArticle

Preliminary Investigation of the Process Capabilities of Hydroforging

by Bandar Alzahrani and Gracious Ngaile

Materials 2016, 9(1), 40; https://doi.org/10.3390/ma9010040 - 12 Jan 2016

Cited by 15 | Viewed by 6332

Abstract

Hydroforging is a hybrid forming operation whereby a thick tube is formed to a desired geometry by combining forging and hydroforming principles. Through this process hollow structures with high strength-to-weight ratio can be produced for applications in power transmission systems and other structural [...] Read more.

Hydroforging is a hybrid forming operation whereby a thick tube is formed to a desired geometry by combining forging and hydroforming principles. Through this process hollow structures with high strength-to-weight ratio can be produced for applications in power transmission systems and other structural components that demands high strength-to-weight ratio. In this process, a thick tube is deformed by pressurized fluid contained within the tube using a multi-purpose punch assembly, which is also used to feed tube material into the die cavity. Fluid pressure inside the thick tube is developed by volume change governed by the movement of the punch assembly. In contrast to the conventional tube hydroforming (THF), the hydroforging process presented in this study does not require external supply of pressurized fluid to the deforming tube. To investigate the capability of hydroforging process, an experimental setup was developed and used to hydroforge various geometries. These geometries included hollow flanged vessels, hexagonal flanged parts, and hollow bevel and spur gears. Full article

(This article belongs to the Special Issue Forming of Light Weight Materials)

► Show Figures

Figure 1

2343 KiB

Open AccessArticle

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

by Choon-Sang Park, Dong Ha Kim, Bhum Jae Shin and Heung-Sik Tae

Materials 2016, 9(1), 39; https://doi.org/10.3390/ma9010039 - 11 Jan 2016

Cited by 34 | Viewed by 8195

Abstract

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a [...] Read more.

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES) techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and gel permeation chromatography (GPC) techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (M_w), about 533 kDa with 1.9 polydispersity index (PDI). This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

► Show Figures

Figure 1

2336 KiB

Open AccessFeature PaperArticle

Antimicrobial Properties and Cytocompatibility of PLGA/Ag Nanocomposites

by Mariangela Scavone, Ilaria Armentano, Elena Fortunati, Francesco Cristofaro, Samantha Mattioli, Luigi Torre, Jose M. Kenny, Marcello Imbriani, Carla Renata Arciola and Livia Visai

Materials 2016, 9(1), 37; https://doi.org/10.3390/ma9010037 - 11 Jan 2016

Cited by 23 | Viewed by 5971

Abstract

The purpose of this study was to investigate the antimicrobial properties of multifunctional nanocomposites based on poly(dl-Lactide-co-Glycolide) (PLGA) and increasing concentration of silver (Ag) nanoparticles and their effects on cell viability for biomedical applications. PLGA nanocomposite films, produced by solvent casting [...] Read more.

The purpose of this study was to investigate the antimicrobial properties of multifunctional nanocomposites based on poly(dl-Lactide-co-Glycolide) (PLGA) and increasing concentration of silver (Ag) nanoparticles and their effects on cell viability for biomedical applications. PLGA nanocomposite films, produced by solvent casting with 1 wt%, 3 wt% and 7 wt% of Ag nanoparticles were investigated and surface properties were characterized by atomic force microscopy and contact angle measurements. Antibacterial tests were performed using an Escherichia coli RB and Staphylococcus aureus 8325-4 strains. The cell viability and morphology were performed with a murine fibroblast cell line (L929) and a human osteosarcoma cell line (SAOS-2) by cell viability assay and electron microscopy observations. Matrix protein secretion and deposition were also quantified by enzyme-linked immunosorbent assay (ELISA). The results suggest that the PLGA film morphology can be modified introducing a small percentage of silver nanoparticles, which induce the onset of porous round-like microstructures and also affect the wettability. The PLGA/Ag films having silver nanoparticles of more than 3 wt% showed antibacterial effects against E. coli and S. aureus. Furthermore, silver-containing PLGA films displayed also a good cytocompatibility when assayed with L929 and SAOS-2 cells; indicating the PLGA/3Ag nanocomposite film as a promising candidate for tissue engineering applications. Full article

(This article belongs to the Special Issue Anti-Infective Materials in Medicine and Technology)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Materials, Volume 9, Issue 1 (January 2016) – 66 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI