Lună: februarie 2016

Nanotehnologia în textile – noul negru

Acoperirea suprafeței textile și îmbrăcăminte cu nanoparticule este o abordare a producției de suprafețe extrem de active pentru a avea UV-blocare, antimicrobiene, antistatic retardant, flacără, apă și ulei hidrofug, rezistent la rid, și auto-curățare properties.One obstacol încăpățânat făcut previne textile îmbunătățită nanomaterial de a deveni mai mult o realitate comercială este insuficientă durabilitatea acoperirilor nano pe fibre textile sau stabilitatea diferitelor proprietăți înzestrate de nanoparticule. Pur și simplu pune, „inteligent“ vine de pe timpul proprietăților antimicrobiene washing.While sunt exercitate de nano-argint, blocarea UV, auto-curățare și proprietăți ignifuge sunt conferite de acoperiri de oxid de nano-metal. nanoparticule de oxid de zinc încorporate în matrici polimerice, cum ar fi amidon solubil sunt un exemplu bun de nanostructuri funcționale cu potențial de aplicații, cum ar fi: capacitatea de protectie UV in industria textila si de protectie solara si finisaje antibacteriene in textile medicale si interioara Wears

Posted: Feb 29, 2016

Nanotechnology in textiles – the new black

(Nanowerk Spotlight) Nanoengineered functional textiles are going to revolutionize the clothing that you’ll wear. The potential of nanotechnology in the development of new materials in the textile industry is considerable. On the one hand, existing functionality can be improved using nanotechnology and on the other, it could make possible the manufacture of textiles with entirely new properties or the combination of different functions in one textile material (read our previous Nanowerk Spotlight on this topic: „Nanotechnology textiles„).Applications of nanotechnology in textilesApplications of nanotechnology in textiles. (Reprinted with permission by American Chemical Society)A first generation of nano-enhanced textiles benefitted from nano finishing: Coating the surface of textiles and clothing with nanoparticles is an approach to the production of highly active surfaces to have UV-blocking, antimicrobial, antistatic, flame retardant, water and oil repellent, wrinkle resistant, and self-cleaning properties.One stubborn hurdle that prevents nanomaterial-enhanced textiles from becoming more of a commercial reality is the insufficient durability of nanocoatings on textile fibers or the stability of various properties endowed by nanoparticles. Quite simply put, the ‘smart’ comes off during washing.While antimicrobial properties are exerted by nano-silver, UV blocking, self-cleaning and flame-retardant properties are imparted by nano-metal oxide coatings. Zinc oxide nanoparticles embedded in polymer matrices like soluble starch are a good example of functional nanostructures with potential for applications such as UV-protection ability in textiles and sunscreens, and antibacterial finishes in medical textiles and inner wears (read more about nanofinishing in textile technology).Permethrin-releasing textile net on a body suitSandy Mattei models a design by Matilda Ceesay with a Permethrin-releasing textile net. (Image: Cornell University)A just published review paper in the February 26, 2016 online edition of ACS Nano („Nanotechnology in Textiles”) discusses electronic and photonic nanotechnologies that are integrated with textiles and shows their applications in displays, sensing, and drug release within the context of performance, durability, and connectivity.In these smart clothes the textile structures themselves perform electronic or electric functions. Ideally, the nanoelectronic components will be completely fused with the textile material, resulting in that textile and non-textile components cannot be differentiated and ‘foreign particles’ can no longer be seen or felt.

Electronics in textiles

We have written extensively about smart textiles, for instance

In their review, the authors discuss the electrical conductivity of conducting polymers and graphene, both of which are attractive for creating textiles that enable the incorporation of sensors and actuators.Another section of the review is dedicated to power sources suitable for e-textiles. This covers lightweight fabric carbon nanotube supercapacitor electrodes; stretchable graphene and PPy-based supercapacitors; triboelectric nanogenerators; flexible fiber and stripe batteries; and stretchable PPy-based supercapacitors for energy transfer.Schematic illustration of a wearable triboelectric nanogenerator(a) Schematic illustration of a wearable triboelectric nanogenerator. (b) Fabrication process of the nanopatterned PDMS structure. (c) FE-SEM images of the bottom textile with nanopatterned PDMS. Inset is a high-resolution image clearly showing the ZnO NR-templated PDMS nanopatterns. (d) Photographic image of the flexible, foldable WTNG. (Reproduced with permission by American Chemical Society) (click on image to enlarge)Adding digital components to these e-textiles would open up an entirely new area of functional clothing. OLEDs in fiber form could lead to revolutionary applications by integrating optical and optoelectronic devices into textile. Combined with nanoelectronic devices, we might one day see flexible optical sensors and display screens woven into shirts and other garments. You could literally wear your next-generation smart phone or iPad on your sleeves; including the solar panels to power them (read more: „Light-emitting nanofibers shine the way for optoelectronic textiles„).

 

Photonic technologies for textiles

Want your clothes to change color at the push of a button, in response to ambient heat or illumination, warning you about airborne pollutants or pollen, or glow in the dark? The integration of optical technologies into garments will make this possible.As the authors write, „photonic materials and devices including films, nanoadditives, or optical fibers have been adopted in the fabrication of textiles and garments to not only enhance the aesthetic performance but also endow the garments with additional functionalities. The most distinctive and basic application of optical technologies on fabrics or garments is perhaps tuning their appearance by controlling the intensity, color, and pattern of light.”For example, optical films made of periodical dielectric multilayers could be directly coated on fabrics, thus offering a highly reflective colorful appearance and enabling different color perceptions depending on the angle of observation. Holographic films may also achieve similar functions and even provide a more complex 3D visual effect.”

Sensing and drug release in textiles

Lab-on-fiber technology will allow the implementation of sophisticated, autonomous multifunction sensing and actuating systems – all integrated in individual optical fibers. Such multifunctional labs integrated into a single optical fiber, exchanging information and combining sensorial data, could provide effective auto-diagnostic features as well as new photonic and electro-optic functionalities (read more: „Move over chips – here come multifunctional labs on a single fiber„).The general sensing principle of a plasmonic fiber sensor is described in detail in the review paper: „In a plasmonic fiber sensor, a lossy surface plasmon mode propagating along a metal/dielectric interface can be excited at its resonance by an optical fiber core-guided mode via evanescent wave coupling when the phase-matching condition between the two modes is satisfied at a certain frequency. The presence of such a plasmonic mode manifests itself as a spectral dip in the fiber transmission spectrum, with its spectral location corresponding to the phase-matching frequency. Variations in the refractive index of an analyte adjacent to the metal layer could significantly modify the phase-matching condition, thus displacing the spectral dip in the optical fiber transmission spectrum.”Already, temperature, humidity, and pressure sensors have been incorporated in textiles. In future, microfluidics can be incorporated in thread-based channels for application in point-of-care diagnostics. Combined with LEDs, these textiles can give visual sensing information. Combined with drug-loaded nanoparticles, textile fibers could provide programmable release of therapeutic drugs.For example, the designer Matilda Ceesay created a hooded body suit embedded at the molecular level with insecticides to ward off mosquitoes infected with malaria. The cotton mesh used for this anti-malaria garment was coated with a material where an insect repellent and fabric are bound at the nano level using metal organic framework molecules (MOFs).Concluding their review, after an extensive discussion of fabrication methods and functionalities, the authors also address the issues of toxicity of nanomaterials in textiles as well as commercial trends in the global nanotechnology-enhanced textile market.By Michael is author of two books by the Royal Society of Chemistry: Nano-Society: Pushing the Boundaries of Technology and Nanotechnology: The Future is Tiny.

Read more: Nanotechnology in textiles – the new black

Nanotehnologia în textile – noul negru(Nanotechnology in textiles -the new black)

potențialul nanotehnologiei în dezvoltarea de noi materiale în industria textilă este considerabil;autorii abordează, de asemenea, problemele legate de toxicitatea nanomaterialelor din textile, precum și tendințele comerciale în domeniul nanotehnologiei globale – îmbunătățirea pieței textile

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Controlerul piezo-digital de înaltă performanță PI de înaltă performanță este prea eficient din punct de vedere al costurilor

Specificații, foaie de date, mai multe informații
Aplicațiile E-727
Aplicațiile includ nanopoziția, nano-automatizarea, tehnologia semiconductorilor, fotonica, bio-nanotehnologia, metrologia, microscopia, micro-manipularea, inclusiv aplicațiile curate.
Caracteristici și avantaje
– Servo Digital pentru algoritmi avansați de control
– Lățime de bandă de control de 25 kHz
– Pentru senzori de feedback cu capacitate și piezo-rezistență
– Intrări și ieșiri de control analogic de înaltă rezoluție
– Interfețe: Ethernet, USB și RS-232
– Intrări și ieșiri digitale
– DSP 32/64-bit, Floating Point, 375 MHz
– DAC pe 20 biți și rezoluție ADC
– ID Chip compatibil pentru interschimbabilitatea controlerului și a mecanicii
– Linia 4 din ordinul polinomial

 

Posted: Feb 29, 2016

PI’s New High Performance Multi-Channel Digital Piezo Controller is Cost-Effective Too
(Nanowerk News) PI (Physik Instrumente) L.P., an industry leader in precision motion components, systems, and solutions, has released a new, high-performance 3 and 4-channel digital piezo controller that integrates with a wide range of existing piezo-based nanpositioning systems and piezo actuators.
E-727 controller
Lower Price, Higher Performance
The new E-727 replaces the E-725 controller and combines higher performance with a lower price. Compared to its predecessor, it provides 3 additional high-resolution analog interfaces, a faster servo, as well as a broader choice of traditional, high-speed, and real time digital interfaces, such as SPI, Ethernet, USB and RS-232
Ultra-Low Noise Controller
20-bit DAC & ADC converters keep the closed-loop E-727 controller operating with high resolution and ultra-low noise, along with 4 integrated power amplifiers for multilayer piezo drives with operating voltage of -30 to +130V. Closed-loop nanopositioning systems are supported with capacitive feedback sensors, piezoresistive sensors, and traditional strain gauges. In addition to PID control, 2 additional user programmable notch filters are implemented for suppression of mechanical system resonances. Linearization based on 4th order polynomials provides higher positioning accuracy. The Dynamic Digital Linearization (DDL) feature eliminates non-linearities at high operating frequencies.
Data Recorder, Auto-Calibration ID Chip, Quick Start UP, Comprehensive Software Package The cost-effective E-727 has a data recorder for high speed tracing, ID chip compatibility for quick start-up, and exchange of system components without recalibration, and the additional feature of programmable drift compensation. The controller comes with extensive software support for LabVIEW and shared libraries for Windows and Linux. Multiple digital interfaces for ease of control: Ethernet, USB, RS-232, SPI. Four (4) digital I/O channels as well as four (4) high-resolution analog inputs and outputs each are also available for use with external sensors, target values or external amplifiers.
Specifications, Datasheet, More Information
Applications of the E-727
Applications include nanopositioning, nano-automation, semiconductor technology, photonics, bio-nano-technology, metrology, microscopy, micro-manipulation, including cleanroom applications.
Features & Advantages
  • – Digital Servo for Advanced Control Algorithms
  • – 25 kHz Control Bandwidth
  • – For Capacitive and Piezo-restive Strain Gauge Feedback Sensors
  • – High Resolution Analog Control Inputs and Outputs
  • – Interfaces: Ethernet, USB, and RS-232
  • – Digital Inputs and Outputs
  • – DSP 32/64-bit Floating Point, 375 MHz
  • – 20-bit DAC and ADC Resolution
  • – ID Chip Compatible for Interchangeability of Controller and Mechanics
  • – 4th Order Polynomial Linearization for Mechanics & Electronics
About PI
PI is a leading manufacturer of precision motion control equipment, piezo motors, air bearing stages and hexapod parallel-kinematics for semiconductor applications, photonics, bio-nano-technology and medical engineering. PI has been developing and manufacturing standard & custom precision products with piezoceramic and electromagnetic drives for 4 decades. The company has been ISO 9001 certified since 1994 and provides innovative, high-quality solutions for OEM and research. PI is present worldwide with eleven subsidiaries, R&D / engineering on 3 continents and total staff of 800+.
Source: PI (press release)

Read more: PI’s New High Performance Multi-Channel Digital Piezo Controller is Cost-Effective Too

Scrutând(cercetand) vârful sondelor moleculare

Autorii au folosit date din spectroscopie infraroșie și termogravimetrie pentru a identifica rezistența interacțiunii dintre sondă și suprafața de oxid, care le-a ajutat, de asemenea, să determine tipul de legare la suprafață.
Ei au stabilit doi parametri cheie: în primul rând, densitatea speciilor de suprafață adsorbite utilizate pentru a caracteriza interacțiunea moleculei de sondă cu suprafața. Acest parametru depinde de natura nanoparticulelor de oxid și de existența nanoporilor. Al doilea parametru exprimă raportul dintre moleculele conținute în stratul de suprafață având un comportament dinamic din sticlă față de numărul total al moleculelor adsorbite.
Studiul arată că valoarea densității de suprafață poate fi utilizată pentru a diviza compozitele în mai multe grupuri. Acest lucru ajută la determinarea faptului că moleculele de sondă aplicate pe suprafața unui grup dat pot prezenta interacțiuni similare, așa cum se observă în suprafețele aceleiași familii.

Posted: Feb 29, 2016

Scrutinizing the tip of molecular probes

(Nanowerk News) Studies of molecules confined to nano- or micropores are of considerable interest to physicists. That’s because they can manipulate or stabilise molecules in unstable states or obtain new materials with special properties.
In a new study published in EPJ Plus („Rod-like cyanophenyl probe molecules nanoconfined to oxide particles: Density of adsorbed surface species”), Stefan Frunza from the National Institute of Materials Physics in Romania and colleagues have discovered the properties of the surface layer in probe molecules on the surface of oxide particles. These properties depend on the interaction at the interface.
In this particular study, probes are formed by adsorption of rod-like cyanophenyl derivates on the surface of oxide particles. The authors found that their surface layers behave like glass-forming liquids.
The solid lines indicate the temperature range used to estimate the amount of molecules loaded onto the probe
The solid lines indicate the temperature range used to estimate the amount of molecules loaded onto the probe.
What physicists already knew is that confinement of molecules may induce disorder. Confinement and disorder have a considerable influence both on the structure of the trapped molecule but also on its mobility. As a result, they also affect aspects such as molecular dynamics upon relaxation of the material. Such structurally well-defined monolayers on solid surfaces will allow researchers to model a large variety of interfacial phenomena.
The authors used data from infrared spectroscopy and thermogravimetry to identify the strength of the interaction between the probe and the oxide surface, which also helped them determine the type of bonding to the surface.
They established two key parameters: firstly, the density of the adsorbed surface species used to characterise the interaction of the probe molecule with the surface. This parameter depends on the nature of the oxide nanoparticles and on the existence of nanopores. The second parameter expresses the ratio of the molecules contained in the surface layer having a glassy dynamic behaviour to the total number of the adsorbed molecules.
The study shows that the value of the surface density can be used to divide the composites into several groups. This helps to determine that the probe molecules applied to the surface of a given group can display similar interactions, as observed in surfaces of the same family.
Source: SciencePOD

Read more: Scrutinizing the tip of molecular probes

Forma nouă a imaginilor cu fascicul de electroni poate vedea elemente care sunt „invizibile” pentru metodele comune

Această placă de fază modifică fasciculul de electroni într-un mod care permite modificarea subtilă a unui material care poate fi măsurat, chiar dezvăluind materiale care ar putea fi invizibile în imaginile STEM tradiționale.
O altă metodă bazată pe electroni, pe care cercetătorii o utilizează pentru a determina structura detaliată a probelor biologice delicate și congelate, se numește microscopie crioelectronică sau crio-EM. În timp ce cryo-EM cu particule unice este un instrument puternic – a fost numit ca revista științifică Nature’s 2015 Method of the Year – este de obicei nevoie de a lua o medie peste multe eșantioane identice pentru a fi eficiente. În general, Cryo-EM nu este util pentru studierea probelor cu un amestec de elemente grele (de exemplu, majoritatea tipurilor de metale) și elemente ușoare cum ar fi oxigenul și carbonul.
Metoda MIDI-STEM ofera speranta pentru a vedea structuri cu un amestec de elemente grele si luminoase, chiar si atunci cand acestea sunt adunate in stransa legatura

Posted: Feb 29, 2016

New form of electron-beam imaging can see elements that are ‘invisible’ to common methods

(Nanowerk News) Electrons can extend our view of microscopic objects well beyond what’s possible with visible light – all the way to the atomic scale. A popular method in electron microscopy for looking at tough, resilient materials in atomic detail is called STEM, or scanning transmission electron microscopy, but the highly-focused beam of electrons used in STEM can also easily destroy delicate samples.
This is why using electrons to image biological or other organic compounds, such as chemical mixes that include lithium – a light metal that is a popular element in next-generation battery research – requires a very low electron dose.
Scientists at the Department of Energy’sc Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a new imaging technique, tested on samples of nanoscale gold and carbon, that greatly improves images of light elements using fewer electrons.
MIDI-STEM Setup
In MIDI-STEM (right), developed at Berkeley Lab, an electron beam travels through a ringed „phase plate,” producing a high-resolution image (bottom right) that provides details about a sample containing a heavy element (gold) and light element (carbon). Details about the carbon are missing in an image (bottom left) of the sample using a conventional electron imaging technique (ADF-STEM). (Image: Colin Ophus/Berkeley Lab)
The newly demonstrated technique, dubbed MIDI-STEM, for matched illumination and detector interferometry STEM, combines STEM with an optical device called a phase plate that modifies the alternating peak-to-trough, wave-like properties (called the phase) of the electron beam.
This phase plate modifies the electron beam in a way that allows subtle changes in a material to be measured, even revealing materials that would be invisible in traditional STEM imaging.
Another electron-based method, which researchers use to determine the detailed structure of delicate, frozen biological samples, is called cryo-electron microscopy, or cryo-EM. While single-particle cryo-EM is a powerful tool–it was named as science journal Nature’s 2015 Method of the Year –it typically requires taking an average over many identical samples to be effective. Cryo-EM is generally not useful for studying samples with a mixture of heavy elements (for example, most types of metals) and light elements like oxygen and carbon.
„The MIDI-STEM method provides hope for seeing structures with a mixture of heavy and light elements, even when they are bunched closely together,” said Colin Ophus, a project scientist at Berkeley Lab’s Molecular Foundry and lead author of a study, published Feb. 29 in Nature Communications („Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry”), that details this method.
If you take a heavy-element nanoparticle and add molecules to give it a specific function, conventional techniques don’t provide an easy, clear way to see the areas where the nanoparticle and added molecules meet.
„How are they aligned? How are they oriented?” Ophus asked. „There are so many questions about these systems, and because there wasn’t a way to see them, we couldn’t directly answer them.”
While traditional STEM is effective for „hard” samples that can stand up to intense electron beams, and cryo-EM can image biological samples, „We can do both at once” with the MIDI-STEM technique, said Peter Ercius, a Berkeley Lab staff scientist at the Molecular Foundry and co-author of the study.
The phase plate in the MIDI-STEM technique allows a direct measure of the phase of electrons that are weakly scattered as they interact with light elements in the sample. These measurements are then used to construct so-called phase-contrast images of the elements. Without this phase information, the high-resolution images of these elements would not be possible.
In this study, the researchers combined phase plate technology with one of the world’s highest resolution STEMs, at Berkeley Lab’s Molecular Foundry, and a high-speed electron detector.
They produced images of samples of crystalline gold nanoparticles, which measured several nanometers across, and the super-thin film of amorphous carbon that the particles sat on. They also performed computer simulations that validated what they saw in the experiment.
The phase plate technology was developed as part of a Berkeley Lab Laboratory Directed Research and Development grant in collaboration with Ben McMorran at University of Oregon.
The MIDI-STEM technique could prove particularly useful for directly viewing nanoscale objects with a mixture of heavy and light materials, such as some battery and energy-harvesting materials, that are otherwise difficult to view together at atomic resolution.
It also might be useful in revealing new details about important two-dimensional proteins, called S-layer proteins, that could serve as foundations for engineered nanostructures but are challenging to study in atomic detail using other techniques.
In the future, a faster, more sensitive electron detector could allow researchers to study even more delicate samples at improved resolution by exposing them to fewer electrons per image.
„If you can lower the electron dose you can tilt beam-sensitive samples into many orientations and reconstruct the sample in 3-D, like a medical CT scan. There are also data issues that need to be addressed,” Ercius said, as faster detectors will generate huge amounts of data. Another goal is to make the technique more „plug-and-play,” so it is broadly accessible to other scientists.
Source: Lawrence Berkeley National Laboratory

Read more: New form of electron-beam imaging can see elements that are ‘invisible’ to common methods

Nanoparticule pe nanosteps

au dezvoltat un material care menține stabilitatea A unui catalizator „dispersat^ și de constând dintr-un singur atom și de modalitatea de a produce boabe mici de platină prin exploatarea proprietăților substratului
Platina este unul dintre metalele costisitoare utilizate ca catalizatori în noile tehnologii folosite pentru procesele chimice industriale, sursele de energie regenerabilă, controlul poluării și multe alte scopuri. În special, se utilizează pentru celulele de combustie, dispozitive care transformă energia chimică direct în energie electrică, fără ardere. Cercetările au arătat că cea mai mare eficiență este obținută atunci când catalizatorul este disponibil sub formă de nanoparticule (mai mici de 10-9 m). Pur și simplu, cu cât este mai mare dispersia materialului și cu cât dimensiunea particulelor este mai mică, cu atât mai mult este disponibilă pentru cataliză. Din nefericire, legile termodinamicii determină particulele să se „lipsească” unul de celălalt și să formeze clustere mai mari, motiv pentru care materialul devine mai puțin eficient în timp. Deci, ce se poate face pentru a menține dispersia maximă a „nanopulberii”

Posted: Feb 29, 2016

Nanoparticles on nanosteps

(Nanowerk News) New technologies are starved for efficient and inexpensive catalysts. The best materials are made up of nanoparticles, whose properties are the result of their small size. The single catalyst particles have, however, an ugly tendency to cluster into larger particles, thereby reducing their effectiveness. A group of scientists from the International School of Advanced Studies in Trieste and the DEMOCRITOS centre of the Istituto Officina dei Materiali of the Italian National Research Council (IOM-CNR), with the collaboration of other institutions, have developed a material that maintains the stability of a “dispersed” catalyst, thus maximising the efficiency of the process and decreasing costs and wastage.
The study has just been published in Nature Communications („Creating single-atom Pt-ceria catalysts by surface step decoration”).
Nanoparticles
Nanoparticles adhering to steps.
Platinum is one of the costly metals used as catalysts in new technologies employed for industrial chemical processes, renewable energy sources, pollution control and many other purposes. In particular, it is used for fuel cells, devices that turn chemical energy directly into electrical energy, without combustion. Research has shown that the greatest efficiency is achieved when the catalyst is available in the form of nanoparticles (smaller than 10-9 m). Simply put, the greater the dispersion of the material and the smaller the size of the particles, the more is it available for catalysis. Unfortunately, the laws of thermodynamics cause the particles to “stick” to one another and form larger clusters, which is why the material becomes less effective over time. So what can be done to maintain maximal dispersion of the “nanopowder”?
A group of SISSA/CNR IOM scientists (with the collaboration of the Univerzita Karlova in Prague) has studied a way to produce tiny platinum grains consisting of one atom only and to keep them dispersed in a stable manner, by exploiting the properties of the substrate on which they rest.
“Theoretical work demonstrated that irregularities in the surface known as steps and observed in experiments conducted at the Trieste Synchrotron tend to attract and separate the nanoparticles, causing them to remain literally attached in the form of single atoms”, explains Stefano Fabris, CNR-IOM/SISSA research fellow.
“The particles adhering to the steps were no longer visible even using an atomic resolution microscope” explains Nguyen-Dung Tran, a SISSA PhD student. “However, their presence was detected by spectroscopy, so they were indeed there, but they were no longer visible or free to move around”. “Our computer simulations solved this dilemma, showing that the particles on the steps are reduced to single atoms” adds Matteo Farnesi Camellone (CNR-IOM), another author of the study.
“If the surface is engineered to contain a large number of these defects, then the force that binds the particles to the substrate effectively offsets the aggregation force”, explains Fabris. The theoretical work, led by Fabris, allowed the researchers to develop a “system model” on the computer able predict the behaviour of the material. The model’s predictions were confirmed by the experimental measurements. Materials like this can be used for fuel cell electrodes, with far lower costs than the current ones.
“Reducing the amount of platinum used in fuel cell electrodes is a priority, not only to contain costs but also to ensure environmental sustainability, as also indicated by the recent European directives” concludes Fabris. The European project ChipCAT, which funded this research, aims precisely to achieve this goal.
Source: SISSA

Read more: Nanoparticles on nanosteps

Dispozitive electronice extensibile, care au o lungime cvadruple

ar putea fi folosit pentru senzori concepuți pentru a monitoriza anumite funcții biologice.Ideale pentru pielea artificială pe proteze sau mașini robotizateÎnlătură termen: îmbrăcăminte conectată și senzori pe corp îmbrăcăminte conectată și senzori pe corp

Posted: Feb 29, 2016

Stretchable electronics that quadruple in length (w/video)

(Nanowerk News) EPFL researchers have developed conductive tracks that can be bent and stretched up to four times their original length. They could be used in artificial skin, connected clothing and on-body sensors.
stretchable electronics
Conductive tracks are usually hard printed on a board. But those recently developed at EPFL are altogether different: they are almost as flexible as rubber and can be stretched up to four times their original length and in all directions. And they can be stretched a million times without cracking or interrupting their conductivity. The invention is described in an article published today in the journal Advanced Materials („Intrinsically Stretchable Biphasic (Solid–Liquid) Thin Metal Films”).
Both solid and flexible, this new metallic and partially liquid film offers a wide range of possible applications. It could be used to make circuits that can be twisted and stretched – ideal for artificial skin on prosthetics or robotic machines. It could also be integrated into fabric and used in connected clothing. And because it follows the shape and movements of the human body, it could be used for sensors designed to monitor particular biological functions.
“We can come up with all sorts of uses, in forms that are complex, moving or that change over time,” said Hadrien Michaud, a PhD student at the Laboratory for Soft Bioelectronic Interfaces (LSBI) and one of the study authors.
Extensive research has gone into developing an elastic electronic circuit. It is a real challenge, as the components traditionally used to make circuits are rigid. Applying liquid metal to a thin film in polymer supports with elastic properties naturally seems like a promising approach.
Thin and reliable
Owing to the high surface tension of some of these liquid metals, experiments conducted so far have only produced relatively thick structures. “Using the deposition and structuring methods that we developed, it’s possible to make tracks that are very narrow – several hundredths of a nanometer thick – and very reliable,” said Stéphanie Lacour, holder of the Bertarelli Foundation Chair in Neuroprosthetic Technology and who runs the lab.
Apart from their unique fabrication technique, the researchers’ secret lies in the choice of ingredients, an alloy of gold and gallium.
“Not only does gallium possess good electrical properties, but it also has a low melting point, around 30o,” said Arthur Hirsch, a PhD student at LSBI and co-author of the study. “So it melts in your hand, and, thanks to the process known as supercooling, it remains liquid at room temperature, even lower.” The layer of gold ensures the gallium remains homogeneous, preventing it from separating into droplets when it comes into contact with the polymer, which would ruin its conductivity.
Source: By Sarah Perrin, École polytechnique fédérale de Lausanne (EPFL)

Read more: Stretchable electronics that quadruple in length (w/video)

Un nou material 2-D ar putea ridica grafenul

Au demonstrat că prin combinarea celor trei elemente este posibil să se obțină un material de 2 atomi gros, cu adevărat 2D, cu proprietăți care pot fi reglate pentru a se potrivi diferitelor aplicații dincolo de ceea ce este posibil cu grafenul

Posted: Feb 29, 2016

New 2-D material could upstage graphene

(Nanowerk News) A new one atom-thick flat material that could upstage the wonder material graphene and advance digital technology has been discovered by a physicist at the University of Kentucky working in collaboration with scientists from Daimler in Germany and the Institute for Electronic Structure and Laser (IESL) in Greece.
Reported in Physical Review B, Rapid Communication („Prediction of a new graphenelike Si2BN solid”), the new material is made up of silicon, boron and nitrogen – all light, inexpensive and earth abundant elements – and is extremely stable, a property many other graphene alternatives lack.
New Material Made of Silicon, Boron and Nitrogen
The atoms in the new structure are arranged in a hexagonal pattern as in graphene, but that is where the similarity ends. The three elements forming the new material all have different sizes; the bonds connecting the atoms are also different. As a result, the sides of the hexagons formed by these atoms are unequal, unlike in graphene. (Image: Madhu Menon)
„We used simulations to see if the bonds would break or disintegrate – it didn’t happen,” said Madhu Menon, a physicist in the UK Center for Computational Sciences. „We heated the material up to 1,000 degree Celsius and it still didn’t break.”
Using state-of-the-art theoretical computations, Menon and his collaborators Ernst Richter from Daimler and a former UK Department of Physics and Astronomy post-doctoral research associate, and Antonis Andriotis from IESL, have demonstrated that by combining the three elements, it is possible to obtain a one atom-thick, truly 2D material with properties that can be fine-tuned to suit various applications beyond what is possible with graphene.
While graphene is touted as being the world’s strongest material with many unique properties, it has one downside: it isn’t a semiconductor and therefore disappoints in the digital technology industry. Subsequent search for new 2D semiconducting materials led researchers to a new class of three-layer materials called transition-metal dichalcogenides (TMDCs). TMDCs are mostly semiconductors and can be made into digital processors with greater efficiency than anything possible with silicon. However, these are much bulkier than graphene and made of materials that are not necessarily earth abundant and inexpensive.
Searching for a better option that is light, earth abundant, inexpensive and a semiconductor, the team led by Menon studied different combinations of elements from the first and second row of the Periodic Table.
Although there are many ways to combine silicon, boron and nitrogen to form planar structures, only one specific arrangement of these elements resulted in a stable structure. The atoms in the new structure are arranged in a hexagonal pattern as in graphene, but that is where the similarity ends.
The three elements forming the new material all have different sizes; the bonds connecting the atoms are also different. As a result, the sides of the hexagons formed by these atoms are unequal, unlike in graphene. The new material is metallic, but can be made semiconducting easily by attaching other elements on top of the silicon atoms.
The presence of silicon also offers the exciting possibility of seamless integration with the current silicon-based technology, allowing the industry to slowly move away from silicon instead of eliminating it completely, all at once.
„We know that silicon-based technology is reaching its limit because we are putting more and more components together and making electronic processors more and more compact,” Menon said. „But we know that this cannot go on indefinitely; we need smarter materials.”
Furthermore, in addition to creating an electronic band gap, attachment of other elements can also be used to selectively change the band gap values – a key advantage over graphene for solar energy conversion and electronics applications.
Other graphene-like materials have been proposed but lack the strengths of the material discovered by Menon and his team. Silicene, for example, does not have a flat surface and eventually forms a 3D surface. Other materials are highly unstable, some only for a few hours at most.
The bulk of the theoretical calculations required were performed on the computers at the UK Center for Computational Sciences with collaborators Richter and Andriotis directly accessing them through fast networks. Now the team is working in close collaboration with a team led by Mahendra Sunkara of the Conn Center for Renewable Energy Research at University of Louisville to create the material in the lab. The Conn Center team has had close collaborations with Menon on a number of new materials systems where they were able to test his theory with experiments for a number of several new solar materials.
„We are very anxious for this to be made in the lab,” Menon said. „The ultimate test of any theory is experimental verification, so the sooner the better!”
Some of the properties, such as the ability to form various types of nanotubes, are discussed in the paper but Menon expects more to emerge with further study.
„This discovery opens a new chapter in material science by offering new opportunities for researchers to explore functional flexibility and new properties for new applications,” he said. „We can expect some surprises.”
Source: University of Kentucky

Read more: New 2-D material could upstage graphene

Sistemul de livrare a nanotehnologiei oferă o nouă abordare a terapiilor cu boli ale pielii

activeaza in mod eficient apararea naturala a organismului impotriva radicalilor liberi șnanotehnologie care contine un inductor de protectie celulara protectiva

Posted: Feb 29, 2016

Nanotechnology delivery system offers new approach to skin disease therapies

(Nanowerk News) Researchers at The Hebrew University of Jerusalem have developed a nanotechnology-based delivery system containing a protective cellular pathway inducer that activates the body’s natural defense against free radicals efficiently, a development that could control a variety of skin pathologies and disorders.
The human skin is constantly exposed to various pollutants, UV rays, radiation and other stressors that exist in our day-to-day environment. When they filter into the body they can create Reactive Oxygen Species (ROS) – oxygen molecules known as Free Radicals, which are able to damage and destroy cells, including lipids, proteins and DNA.
In the skin – the largest organ of the body – an excess of ROS can lead to various skin conditions, including inflammatory diseases, pigmenting disorders, wrinkles and some types of skin cancer, and can also affect internal organs. This damage is known as Oxidative Stress.
The body is naturally equipped with defense mechanisms to counter oxidative stress. It has anti-oxidants and, more importantly, anti-oxidant enzymes that attack the ROS before they cause damage.
In a review article published in the journal Cosmetics („Skin Redox Balance Maintenance: The Need for an Nrf2-Activator Delivery System”), a PhD student from The Hebrew University of Jerusalem, working in collaboration with researchers at the Technion – Israel Institute of Technology, suggested an innovative way to invigorate the body to produce antioxidant enzymes, while maintaining skin cell redox balance – a gentle equilibrium between Reactive Oxygen Species and their detoxification.
Consequences of skin exposure to stressors
Consequences of skin exposure to stressors (Image: Maya Ben-Yehuda Greenwald) (click on image to enlarge)
„The approach of using the body’s own defense system is very effective. We showed that activation of the body’s defense system with the aid of a unique delivery system is feasible, and may leverage dermal cure,” said Hebrew University researcher Maya Ben-Yehuda Greenwald.
Ben-Yehuda Greenwald showed that applying nano-size droplets of microemulsion liquids containing a cellular protective pathway inducer into the skin activates the natural skin defense systems.
„Currently, there are many scientific studies supporting the activation of the body’s defense mechanisms. However, none of these studies has demonstrated the use of a nanotechnology-based delivery system to do so,” Ben-Yehuda Greenwald said.
Production of antioxidant enzymes in the body is signaled in the DNA by activation of Nrf2 – a powerful protein that exists in every cell in our body. This Nrf2 cellular-protective signaling pathway is a major intersection of many other signaling pathways affecting each other and determining cell functionality and fate. Nrf2 is capable of coordinating the cellular response to internal as well as external stressors by tight regulation of phase-II protective enzymes, such as the antioxidant enzymes.
Ben-Yehuda Greenwald has also discovered a new family of compounds capable of activating the Nrf2 pathway. Moreover, by incorporating them into the unique delivery system she has developed, she managed to efficiently stimulate the activation of the Nrf2 pathway and mimic the activity of the body’s’ natural way of coping with a variety of stress conditions.
„The formula we have created could be used in topical medication for treating skin conditions. Our formula could be used both as preventive means and for treatment of various skin conditions, such as infections, over-exposure to UV irradiation, inflammatory conditions, and also internal disease,” she said.
While the researchers focused on the skin, the formulation could prove to be effective in enhancing the body’s natural protection against the damaging effects of ROS in other parts of the body, such as inflammation in cardiovascular diseases, heart attack, cancer, multiple sclerosis and Alzheimer’s.
Source: Hebrew University of Jerusalem

Read more: Nanotechnology delivery system offers new approach to skin disease therapies