Issue 12

Researcher of the Year for 2017 – A seamless journey of tiny technology

Ashutosh Tiwari

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1089-1093
DOI: 10.5185/amlett.2017.12001

International Association of Advanced Materials (IAAM) names the researcher of the year who had the greatest contribution in the field of Advanced Materials. The advanced materials community would like to take this opportunity to pay rich tributes to Professor Zhong Lin (Z. L.) Wang for his pioneering research and notable contributions to nanoscience and nanotechnology. Advanced Materials Letters have been selected his photo for the cover of this special year-end issue.

Membrane-assisted catalysis in organic media

Levente Cseri; Tamas Fodi; Jozsef Kupai; Gyorgy T. Balogh; Arthur Garforth; Gyorgy Szekely

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1094-1124
DOI: 10.5185/amlett.2017.1541

In the last decades, the rapid advancement of solvent-resistant membranes and catalysis led to the development of more efficient and sustainable materials and processes. The present article critically assesses membrane-assisted catalysis in organic media, which is a multidisciplinary field combining materials science, reaction engineering, organic chemistry, and membrane science and technology. The membranes act either as catalysts directly accelerating the rate of the reaction or as selective barriers for separating homogeneous catalysts from the reaction mixture. The discussions are grouped based on the catalyst type, and introductory tables given for each group allow direct comparison of the literature with regards to reaction type, solvent(s) employed, type of membrane, catalyst rejection, highest conversion and volumetric productivity. Major achievements, limitations and inconsistencies in the field are presented along with future research directions and requirements.

Gold nanoparticle-based biosensors for the assay of tumor marker proteins with clinical applications

Jiehua Ma; Xiaolu Hu; Yaqin Tao; Chao Li; Xiaoxia Mao; Genxi Li

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1125-1131
DOI: 10.5185/amlett.2017.1552

The detection of tumor markers plays an important role in clinical diagnosis and evaluation of therapeutic effect. Early detection of tumor markers, which are usually proteins, can greatly facilitate effective treatment with different modalities and even increase cure rate of patients. Currently, nanoparticle-based methods for cancer diagnostics are becoming an increasingly relevant alternative to traditional techniques. Gold nanoparticles (AuNPs) are one of the most extensively studied nanomaterials due to their remarkable physical and chemical properties. With the recent advances in nanotechnology, AuNPs have offered new ways to detect tumor markers at low concentrations and to target cancer cells in very deep sites. The use of AuNPs may increase the sensitivity of a biosensor and generate higher accuracy and precision of the assays. So, AuNPs have greatly facilitated the development of nanomaterials-based technology for clinic diagnostics and therapy. In this review paper, we have summarized different kinds of AuNPs-based biosensors for the detection of tumor marker proteins with a particular focus on optical and electrochemical techniques, which may provide valuable perspective for the colleagues in the related communities.

Benefits and risks of nanozerovalent iron, titanium dioxide nanoparticles and carbon nanotubes for water treatment technologies

David G. Rickerby

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1132-1144
DOI: 10.5185/amlett.2017.1524

An overview is presented of potential improvements in performance that can be achieved by using three different types of nanomaterials in water treatment applications: (i) zerovalent iron for reducing concentrations of chlorinated hydrocarbons and heavy metals in groundwater; (ii) titanium dioxide for photocatalytic drinking water purification, enabling reduced consumption of chemicals for disinfection; (iii) carbon nanotube membrane filters that transport water molecules at elevated  fluxes, while rejecting other molecules and ions. The distinctive characteristics of the nanomaterials, such as high specific surface area, enhanced reactivity and adsorption capacity, have already led to significant increases in efficiency. Future developments are expected based on surface modification of zerovalent iron to improve its reactivity and transport characteristics, advanced chemical synthesis methods to increase the area of photoreactive facets and doping to inhibit electron-hole recombination or to allow visible light photocatalysis in titanium dioxide, and functionalization of carbon nanotubes to increase ion rejection rates. Implementation of these innovative methods for removal of contaminants from water will be contingent on reduction of the present high cost of the nanomaterials and assessment of the possible risks associated with their, as yet only partly understood, toxic and ecotoxic properties. 

Towards flexible and wearable supercapacitors: A hierarchical approach in material design

Anna Batlle

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1145-1149
DOI: 10.5185/amlett.2017.1680

Wearable devices requires from macroscopic mechanical properties laying in macro-scale in comparison with chemical processes that requires from material design in the nanoscale. Besides, such reactions and phenomena involves charge transfer, and therefore a charge transducer in mean scale is required. In this paper we propose a flexible and wearable supercapacitor that takes advantage of a conductive fabric current collector that is coated by electrospray with MnO2-decorated carbon nanofibers (CNF). The results point out that a high capacitance is obtained due to the pseudocapacitive reactions in MnO2; moreover, the long and conductive structure of CNF allow transferring charge to conductive fabric, keeping a low equivalent serial resistance (ESR). The results indicate a specific capacitance on fabric collector of (226.40 ± 0.3) F/g, about 10 times higher than on aluminum foil collector, with a similar ESR which indicates a suitable way to wearable devices. The proposed technique is scalable, and can be easily applied in the industry. 

Investigation of the effect of copper nanoparticles incorporated in ZnO buffer layer of inverted organic solar cell

B. Parvathy Devi; Sandeep K Das; Yian Tai

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1150-1155
DOI: 10.5185/amlett.2017.1671

This study examines the effect of cheap and easy to synthesize copper nanoparticles (CuNPs) for its surface plasmon resonance behavior on the performance of organic solar cells (OSC). A simple synthesis of stable CuNPs is reported together with a procedure for their optimized incorporation in the OSC architecture via dispersing them on ZnO interfacial layer. The CuNPs triggers the localized surface plasmon resonance resulting in enhancement of short circuit current density under AM1.5 illumination. 

Increasing the metal loading in passion fruit-like nano-architectures

Rosa D

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1156-1160
DOI: 10.5185/amlett.2017.1668

Noble metal nanostructures have demonstrated many intriguing features for both therapy and diagnosis in a number of diseases. However, their clinical translation is prevented by their accumulation in organisms that can result in toxicity and interference with common medical diagnoses. In order to combine the most interesting behaviour of metal nanoparticles with the possibility of their body clearance, we have recently introduced and tested the passion fruit-like nano-architectures. They are versatile 100 nm biodegradable nanostructures composed by a silica shell embedding functional polymeric arrays of ultra-small noble metal nanoparticles. Here, we report a novel simple and robust protocol to increase the loading of ultra small gold nanoparticles in the nano-architectures, promoting their possible application in clinical diagnosis. 

Effect of symmetry on electronic DOS, peierls transition and elastic modulus of carbon nanowires

J. Y. Dai; E. A. Buntov; V. N. Rychkov; M. B. Guseva; A. F. Zatsepin

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1161-1165
DOI: 10.5185/amlett.2017.1578

A Monte Carlo arithmetic method is utilized to investigate the Peierls transition in the linear and circular carbon nanowire respectively. The carbon nanowires interacting with the 6 nearest neighbors in hexagonal structure are spaced by 0.3 nm. Despite the Peierls transition of the linear carbon nanowires is unaffected by the Van der Waal’s force, we discovered that the Peierls transition temperature of the isolated curved nanowire is raised to 910K under curvature. Based on the simulation results, the fluctuation of the atomic position of the atoms are stronger near to the free end boundary condition. Applying stress on the interstitial doped carbon nanowire array examines the elastic modulus which shows above 6TPa. The geometrical effect on the electronic density of states of the kink structural carbon chain is simulated by Harris functional in combination with Local Density Approximation. Two different lengths of branches A and B, are occupied alternatively to generate the asymmetric carbon chain. The ratio of the asymmetric branch length, RAB = A / B, plays an important role in the electronic density of states DOS around Fermi level . The highest DOS(EF) occurs if the RAB equals to 2 and while the Fermi level coincides with the Von-Hove singularity at RAB = 3.

Chitosan bio-functionalization of carbon nanotube arrayed electrode

Hadar Ben-Yoav; Marshall A. Schroeder; Malachi Noked

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1166-1170
DOI: 10.5185/amlett.2017.1577

Nanostructured electrodes enable a new generation of electrochemical sensors by increasing their surface area that lead to stronger signals generated by electrochemically-active molecules, such as diagnostic redox-active biomarkers. Yet, the selectivity of these translational sensors is far from being sufficient for discriminating between individual molecules in multicomponent samples, such as biofluids. Here, we propose an approach to improve the selectivity of nanostructured electrodes using a simple modification with a functional bio-polymer. Specifically, we demonstrate the targeted modification with a bio-polymer chitosan of carbon nanotubes organized in an array on a Au electrode. We describe the fabrication process and we show the characterization of the structural morphology and the electrochemical activity of the fabricated chitosan-modified carbon nanotube arrayed electrode. Electrochemical characterization yielded an increased effective surface area for the optimized carbon nanotube arrayed electrode (0.46 ± 0.03 cm 2 ) that was similar to the area of the unmodified Au electrode (0.48 ± 0.02 cm 2 ). Furthermore, despite decreased electrochemical current characteristics, we demonstrate the feasibility to modify individual carbon nanotubes with chitosan. The modification of the carbon nanostructures with chitosan will enable further functionalization with specific receptors, such as enzymes and antibodies that will provide the required selectivity towards biomarkers in multicomponent biofluids. 

Enhancing significantly the damping response of Mg using hollow glass microspheres while simultaneously reducing weight

Vyasaraj Manakari; Gururaj Parande; Mrityunjay Doddamani; Ganesh Kumar Meenashisundaram; Manoj Gupta

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1171-1177
DOI: 10.5185/amlett.2017.1697

Lightweight composite materials possessing higher damping capabilities are of great interests to material designers satisfying ever changing demands in automotive, aerospace and marine sectors. Besides having lowest density in metals regime, magnesium exhibits superior mechanical properties. Specific properties can still be enhanced by reducing the density further with development of magnesium based syntactic foams. Present work deals with processing and experimental characterization of glass microballoon (GMB) reinforced magnesium (Mg) composites. Hollow glass microspheres (5, 15 and 25 wt.%) reinforced magnesium syntactic foams were synthesized in magnesium matrix using the disintegrated melt deposition (DMD) method and their damping properties are investigated. The addition of glass microspheres enhanced the damping and loss factors by 370% and 12.5 times respectively for the highest filler loading as compared to pure magnesium. Further, increase in damping is correlated with microstructural changes arising due to the presence of the hollow glass microspheres. Elaborate discussion is presented on underlying mechanisms and different phases formed during processing. 

Graphenated ceramic nanofibers for highly sensitive simultaneous detection of dopamine, uric acid and ascorbic acid

Masoud Taleb; Irina Hussainova; Roman Ivanov; Iwona Jasiuk

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1178-1183
DOI: 10.5185/amlett.2017.1557

The present study reports the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in 0.1 M phosphate buffer solution (pH = 7.0) using a novel electrode material prepared from oxide ceramic nanofibers by applying a single step chemical vapor deposition method. Electron-transfer kinetics at the electrode/solution interface was studied by standard redox reaction of 5 mM Fe(CN)6 3-/4- in 1 M KCl. Electrochemical and sensing measurements such as cyclic voltammetry and differential pulse voltammetry were performed to detect DA and UA in the presence of AA. The developed electrode was shown to separate the overlapping voltammetric responses of three analytes into the individual voltammetric peaks, totally eliminate the interference from AA, and distinguish DA from UA. Linear relationship was observed between current intensities and concentrations of all three compounds, and the limits of detection (LOD) were reached 0.57 µM, 0.77 µM and 0.84 µM for DA, UA and AA, respectively. The electrode of graphenated nanofibers displayed a very good reproducibility and stability, and was successfully tested for detection of DA, UA and AA in real urine samples. 

Synthesis of WO3@graphene composite for fructose degradation

Zhenya Jiang; Yao Wang; Lifeng Yan

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1184-1187
DOI: 10.5185/amlett.2017.1660

WO3@Graphene (WO3@GR) nanocomposite has been synthesized by using a simple sonochemical method, and the phosphotungstic acid was used as the source of the WO3 nanoparticles. The new catalyst was analyzed by means of FT-IR, XRD, TEM, and SEM-EDX. FT-IR spectrum of the new material reveals that sulfonic acid groups existed on the surface of graphene nanosheets. In addition, TEM image of WO3@GR indicates that the WO3 nano-particles in size of 5-10 nm have an uniform distribution on the surface of the graphene nanosheets. The as-prepared nanocomposite can be used as a catalyst for biomass conversion, and the catalytic hydrolysis of fructose was carried out at different experiment conditions, such as reaction temperature, reaction time and catalyst dosage. HPLC has been used to measure the compounds in product and their yield. It was found that the major products include HMF, formic acid, lactic acid, acetic acid, and maleic acid, and the maximum yield is 43.25% when the reaction was carried out at 160 o C with the ratio of fructose to catalyst is 8 in the presence of 20 ml of water for 2h. The results reveal that the WO3@GR nanocomposite is a potential catalyst for biomass conversion.

Tunable magnetic anisotropy in epitaxial GaMnAs films: Evidence of temperature control

M. Dehbaoui; S. Kamara; Q. H. Tran; J. Sadowski; J. Z. Domagala; A. Boukra; R. Dumas; S. Charar; F. Terki

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1188-1192
DOI: 10.5185/amlett.2017.1525

The magnetic field dependencies of Hall resistance are studied for Ga0.94Mn0.06As/In0.15Ga0.85As film. The Hall resistance shows a slanted hysteresis cycle, emphasizing the existence of both in-plane and out-of-plane magnetization components. The anisotropy constants of the sample with out-of-plane magnetization are extracted from the angular dependence of Hall resistance measurements. The angular dependence of free magneto-crystalline energy theoretical analysis allows us to confirm the dominance of uniaxial magnetic anisotropy at specific temperatures. Here, precise angular dependence of magnetoresistance Hall Effect measurements and careful analysis using free energy model, enable us to demonstrate how the magnetic easy axis could be reoriented by the temperature within the ferromagnetic phase at the temperature far from the Curie Weiss value. This promising property will offer applicative opportunity of GaMnAs material with temperature induced transition of easy magnetization axis in detection of weak magnetic fields within the cryogenic range of low temperature phenomenon. 

Optical and structural characteristics of ZnO nanopowders for different preparation methods

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1193-1198
DOI: 10.5185/amlett.2017.1581

Zinc oxide (ZnO) nanoparticles (NPs) were synthesized by different methods known as Pechini and Sol-Gel. It was observed during the experiments significant differences comparing these methods as: particle size, time applied, crystallinity and chemical residues generated by-products. The NPs were analysed by X-ray diffraction (XRD), ultraviolet-visible (UV-Vis.) absorption and Raman spectroscopy techniques. X-Ray Difractograms showed peaks corresponding to hexagonal wurtzite crystalline structure. It was observed that NPs obtained by the Pechini showed better homogeneity and crystallinity; these presented average size of 115 nm. The NPs produced by Sol-Gel method showed crystallites with smaller average size of 8 nm. The band gap energy (Eg) obtained using UV-Vis for ZnO NPs synthesized by Pechini was 3.39 eV. Still, the results for Sol-Gel method with 5 and 10 hours of reactions were 3.53 eV and 3.55 eV respectively. Raman data obtained by Pechini and Sol-Gel Methods showed characteristics peaks. The obtained data confirmed the ZnO phase samples and the proportional relationship to the enlargement with the intensity of peaks E2 High ˜ 438 cm -1 , as evidenced by literature. These results lead to the applicability of both NPs in optoelectronic and fluorescent applications. 

Improvement of mechanical properties and surface finish of 3d-printed polylactic acid parts by constrained remelting

Hong-Cheol Kim; Da-Yeong Kim; Ji-Eun Lee; Keun Park

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1199-1203
DOI: 10.5185/amlett.2017.1686

According to recent advancements in additive manufacturing (AM) technology, also known as 3d printing, the role of AM has changed from the conventional rapid prototyping (RP) to direct fabrication of functional parts. The AM technology based on layer-by-layer manufacturing has a limitation in its poor surface finish and mechanical strength, especially along the thickness direction. This study proposes a new post-processing method for thermoplastic AM products with the goal of improving surface finish and mechanical strength. The proposed method, called constrained remelting, uses a metal mould with a negative shape that surrounds the printed polymer part. This mould is heated near the melting temperature of the polymer material so that the printed sample is melted and reshaped inside the mould. To evaluate changes in surface finish and mechanical strength, tensile specimens were printed and tested with various build directions; the tensile test revealed that the Z-directionally printed specimen had much lower mechanical strength than the specimens built along X- or Y- directions. Remelting experiments were then performed for the Z-directionally printed specimen under various remelting conditions (remelting temperature and initial thickness), and the resulting changes in surface finish and tensile strength were investigated. Among these remelting conditions, the 160°C remelting temperature and 4.0 mm thickness condition provided the best result where surface finish and tensile strength were improved significantly so as to be comparable to those of injection-moulded products. 

Magnetic flux channelling in YBa2Cu3O7-δ films grown by a chemical solution deposition technique on vicinal and non-vicinal substrates

Thomas Qureishy; Yue Zhao; Yan Xu

Advanced Materials Letters, 2017, Volume 8, Issue 12, Pages 1204-1210
DOI: 10.5185/amlett.2017.1474

Magneto-optical imaging of YBa2Cu3O7-δ films with high critical current density, synthesized by a cost-effective metal organic decomposition technique reveals inhomogeneous flux penetration in the specimens in the form of thin parallel lines. The origin of such a stripy pattern and its dependence on the sample preparation conditions and state of substrate is discussed. The stripes reflect accumulation of planar defects forming parallel lines of reduced in-plane critical current density, jc, perpendicular to planar defects and enhanced jc parallel to them. Such channel-like reduction and corresponding enhancement of jc is especially expressed in a sample deposited on vicinal substrate, which, as a consequence, demonstrates global temperature-dependent in-plane anisotropy with an anisotropy ratio up to 2.4. The directional enhancement of critical current density due to planar defects could be beneficial for practical use of superconducting films.