Volume 9, Issue 5, May 2018

Towards airflow sensors with energy harvesting and wireless transmitting properties

Tomasz Blaszczyk; John Aa. Sørensen; Per Lynggaard; Kristian Larsen

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 311-319
DOI: 10.5185/amlett.2018.1925

The rapidly growing demand for even more detailed low-cost measurements of weather and environmental conditions, including wind flow, asks for self-sustained energy solutions that eliminate the need for external recharge or replacement of batteries.  Today’s wind measurement market is limited to traditional anemometers, ultrasonic measurement or expensive LIDAR (Light Imaging, Detection and Ranging) systems. This paper presents the initial design considerations for a low-cost combined air speed and wind direction sensor, which harvests energy to drive it and to power the wireless transmission of system configurations and measurements. An energy-budget for this transmission is included.

Investigation of new antifrictional/frictional nanocomposites based on PTFE matrix filled with Fe-doped carbon nanoparticles

Elguja Kutelia; David Gventsadze; Olga Tsurtsumia; Leri Rukhadze; Nikoloz Jalabadze; Tengiz Kukava; Teimuraz Dzigrashvili

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 320-325
DOI: 10.5185/amlett.2018.1988

The present work is dealing with the study of a nano-compositional material which was obtained on the basis of PTFE with 2.5÷10wt% of core-shell type Fe-doped carbon nano-tubes and carbon nano-particles as fillers. The PTFE samples without the fillers were prepared too. Weight wear, friction coefficient and temperature were measured after passing some velocity steps, and afterwards the linear wear was calculated. The obtained results have shown that the incorporation of about 2,5÷5wt% of Fe-doped CNTs into PTFE matrix drastically improves the antifrictional properties in comparison to the unfilled PTFE. Namely, the wear resistance of these nanocompositions increased by the factor of 500-150 in the range of friction velocities 0.25÷1.25 m/sec. Increase of the filler portion up to 10wt% transforms the obtained nanocomposite from antifrictional to friction material with the enhanced coefficient of friction up to 0.32, but with the unexpectedly ultra-low wear. SEM-EDX analyses of the worn surfaces of the tested nanocomposites and the cast iron samples after working as a tribological pair, revealed some favorable effects of the Fe-doped CNTs filler on the formation mechanism of a transfer film and its role in promoting very low wear of the obtained new nanocomposites.

Preparation of polymer nano-photocatalysts by using triton X-100 to improve performance of photocatalytic hydrogen generation

Yanyu Zhang; Palas Baran Pati; Haining Tian

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 326-330
DOI: 10.5185/amlett.2018.1833

Organic semiconducting polymer nano-particles, as nano-photocatalysts for light driven proton reduction, have been prepared by using Triton X-100 as surfactant. The nano-photocatalysts prepared by Triton X-100 showed well dispersibility in water and no precipitation observed after photocatalysis. The effect of molecular weight and concentration on photocatalysis has been investigated, indicating that the particle size shows significant influence on photocatalytic performance. The sample with 100 µg/ml photocatalysts gave the best hydrogen evolution amount of 0.4 µmol/ml and apparent quantum yield of 1.3% at 450 nm.

Phosphorus/reduced graphene oxide nanocomposite for high-performance anode of sodium-ion batteries 

Meng Li; Su Dou; Na Feng; Xiong Pu; Weiguo Hu

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 331-335
DOI: 10.5185/amlett.2018.1871

The red phosphorus is considered as a promising anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity of 2596 mAh/g. However, red phosphorus suffers from some limitations, such as low electronic conductivity, and huge volume expansion in the process of discharging. Herein, we report a high-performance anode with red phosphorus (rP)/reduced graghene oxide (rGO) nanocomposite via vaporization-condensation method. The resulting nanostructured rP is uniformly distributed on the surfaces of rGO. The obtained rP/rGO anode achieves high reversibility (76.85% initial columbic efficiency), high specific discharge capacity (1582.3 mAh/g at 260 mA/g), stable cycling performances (60.2% capacity retention after 50 cycles), and high rate performances (up to 7800 mA/g current density). These high performances of our nanocomposite materials suggest that the rP/rGO anode is of great potential for future high energy SIBs.

Recent advances in lithium-air batteries 

Chunwen Sun

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 336-344
DOI: 10.5185/amlett.2018.1854

Lithium (Li)-ion batteries will play a key role in the electrification of transport, including electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs). However, the present energy storage of Li-ion batteries cannot meet the requirements of transportation in terms of driving range and safety. As a kind of potential alternative energy storage devices, rechargeable Li-air batteries have become one of the most attractive candidates for energy storage and EVs. Li-air batteries can provide several times higher energy density/specific energy of the existing battery systems. In this paper, we mainly focus on the research status, especially some progresses made in our lab, existing challenges and their solutions as well as perspective on the future directions on lithium-air batteries.

Fabrication and magnetic properties of Sol-Gel derived NiZn ferrite thin films for microwave applications

Shauna Robbennolt; Stephen S. Sasaki; Tylisia Wallace; Marquise Bartholomew; Sarah H. Tolbert

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 345-352
DOI: 10.5185/amlett.2018.1996

We present a new solution-phase, sol-gel based spin-coating method to fabricating high quality, nickel zinc ferrite (NZFO) thin films. The effect of annealing temperature on the microstructure, static magnetic properties and X-band FMR linewidth and resonance field was investigated. Furthermore, the effect of composition on these properties was explored in films with the formula NixZn(1-x)Fe2O4 (where x = 0 to 1 in 0.1 increments). Films annealed at the highest annealing temperature of 1100 ?C were found to have the highest saturation magnetization and coercivity, as well as the lowest FMR linewidths. Films with the composition Ni0.3Zn0.7Fe2O4 were found to have the lowest linewidths along with favorable magnetic properties for microwave applications. The champion film showed an FMR linewidth of 93 G, corresponding to a low Gilbert damping coefficient of α = 0.003, a saturation magnetization of 330 emu/cm 3 , and a coercivity and anisotropy field of 14 and 62 Oe respectively.

Symmetrical and unsymmetrical squaraine sensitizers for dye-sensitized solar cells: present day advances and future challenges

Sultan A. Al-horaibi; S.T. Gaikwad; Anjali S. Rajbhoj

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 353-362
DOI: 10.5185/amlett.2018.1740

The requirement for energy is ever increasing in the past few years due to the need for the innovation of clean energy and eco-friendly technologies. Symmetric and asymmetric squaraine dyes have received increasing attention and great potential for use as squaraine sensitizers for application in dye-sensitized solar cells (DSSC). This review article gives a synopsis of the advancements on squaraine sensitizers in the domain of DSSC and the chance used to enhance their overall energy conversion efficiency. Specifically, the primary factors in charge of the low values of open-circuit voltage (Voc), short-circuit photocurrent (Jsc) and fill factor (FF) are debated in detail. Future orientations in research and expanded absorptions of near infrared region (NIR) by development of organic substances and their applications are suggested from a personal point of view.

Effect of electrode material on piezoelectric output of PVDF sensor with electrospun nanofiber web

Hu Jiyong; Gu Yuanyuan; Zhang Hele; Zhu Yinda; Yang Xudong

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 363-368
DOI: 10.5185/amlett.2018.1958

The electrospun PVDF (Polyvinylidene Fluoride) nanofiber web is commonly agreed on a kind of new sensitive materials for the sensor testing the dynamic pressure and energy harvesting, and has the characteristics of fast response and high sensitivity of pressure. As a result of the nanofiber web, it must be packaged to collect piezoelectric charge and bear strong mechanical behavior before industrial practice. The packaging of PVDF nanofiber web is usually sandwiched by incorporating a pair of flexible electrode. However, the effects of the surface and mechanical properties of electrodes such as morphology, roughness and compressibility have not been well investigated yet. This work will introduce three common types of packaging electrode materials (adhesive copper foil tape, indium tin oxide (ITO) thin film, adhesive conductive cloth.) in previously published literatures, compares the piezoelectric output of their sensor prototypes under a periodic impact, and discusses the effect of surface morphology, electrical resistance, and compressibility. The results showed that it has higher output of PVDF piezoelectric sensor packaged by electrode materials with the smooth surface and low mechanical compressibility. This result provides a guideline for designing the textile electrode material for the PVDF nanofiber web.

A sensitive electrochemical aptasensor based on single wall carbon nanotube modified screen printed electrode for detection of Escherichia coli O157:H7

M.R. Housaindokht; E. Sheikhzadeh; P. Pordeli; Z. Rouhbakhsh Zaeri; F. Janati-Fard; M. Nosrati M. Mashreghi; A. Nakhaeipour; A. A. Esmaeili; S. Solimani

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 369-374
DOI: 10.5185/amlett.2018.1701

Escherichia coli O157:H7 (E.coli O157:H7), is an extremely infectious and potentially fatal water and food-borne pathogen, responsible for numerous hospitalisations and deaths all over the world. Herein we reported the development of simple and label-free electrochemical aptasensor based on single wall carbon nanotube (SWCNT) modified screen printed electrode (SPE) to detect E.coli O157:H7 bacteria. The electrochemical probe of methylene blue (MB) was used to investigate the interactions between aptamer and E.coli O157:H7. The resulting MB/Apt/SWNT/SPE layer exhibited good current response to detect E.coli O157:H7. The aptasensor detect E.coli O157:H7 in the concentration range of 1.7×10 1 - 1.1×10 7 CFU mL -1 and limit of quantification of 1.7×10 1 CFU mL -1 . The proposed aptasensor is rapid, convenient and low-cost for effective sensing of E.coli O157:H7 with high selectivity over interference bacteria. The suitability of the aptasensor for real sample measurements was investigated by recovery studies in tap water sample. 

Isothermal aging characteristics of rare earth magnesium hexaaluminate based advanced thermal barrier coatings

Premanshu Jana; Santanu Mandal;Koushik Biswas; Ponnarassery S Jayan

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 375-382
DOI: 10.5185/amlett.2018.1674

The isothermal aging characteristics of rare earth magnesium hexaaluminate (REMHA) based thermal barrier coatings (TBC) such as lanthanum magnesium hexaaluminates (LMHA), Neodymium doped LMHA (LNMHA) and LNMHA-Yttrium aluminium garnet (YAG) composite were evaluated at 1400 °C and compared with standard yttria stabilized zirconia (YSZ) coating. The platelet structure of hexaaluminate forms meso-porous structure and provides superior sintering resistance than YSZ coating. Faster grain growth kinetics is observed in YSZ coating as compared to hexaaluminate-based coatings. As a result, the mechanical properties of YSZ coating deteriorate severely whereas hexaaluminate based coating remains almost unaltered. The LNMHA coating is found to be the best sintering resistance among them. LNMHA and LNMHA-YAG composite have potential to meet the requirement of advanced TBC operating even at 1400 °C. 

Synthesis of fluorescent water-soluble oligo (oxazoline-ethylenimine) block copolymers

Rita F. Pires; Joana Frutuoso; Ana Sofia Cortes; Ana Aguiar-Ricardo; Vasco D. B. Bonifácio

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 383-386
DOI: 10.5185/amlett.2018.1822

The synthesis of new block copolymers of oligo-2-oxazoline and linear oligo(ethylenimine), performed using a green protocol, is described. The synthesis follow a new strategy that allow a precise control the oligo(ethylenimine) backbone. The block copolymers are water-soluble and show an intrinsic blue fluorescence.

Electromagnetic shielding capability of magnesium based materials: A review 

Rachit Pandey; Manoj Gupta

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 387-391
DOI: 10.5185/amlett.2018.1945

The rapid progress in the expanse of electromagnetic devices among the broad scale of industrial, military, commercial and consumer sector has led to a surge in electromagnetic interference which has now become the fourth most prevalent category of pollution. Thus, there is a dire need of developing materials which can shield the devices of its adverse effects. This review sets foot into what so far has been done in order to develop such shielding materials by targeting Mg. The dependence in shielding effectiveness on variation in heat treatment, concentrations of the alloying elements, forming processes and its combinations have been addressed in this review.