Biography:

Nekane Guarrotxena has done her PhD from the University of Complutense, Madrid-Spain and Post-doctoral Research from the Ecole Nationale Supérieure of Arts and Crafts (ENSAM), Paris-France and the University of Science II, Montpellier-France. She was the Vice-Director of the Institute of Polymer Science and Technology (ICTP-CSIC) (2001-2005) and Visiting Professor at the University of California, Santa Barbara-USA and the CaSTL at University of California, Irvine-USA (2008-2011). She is currently a Research Scientist at ICTP-CSIC (Spain), Editorial Board Member of some Materials Science and Chemistry journals and External Expertise Consultant on I+D+I Management Policy for national and international agencies. Her research interest focuses on the synthesis and assembly of hybrid nanomaterials, nanoplasmonics, and their uses in nano biotechnology applications (bioimaging, drug delivery, therapy and biosensing).

Abstract:

The noticeable physicochemical properties of colloidal nanoparticles (NPs) have made this class of materials very promising for several applications in all nano-related fields (science, technology and medicine). These size- and shape- dependent tunable properties can also be tailored by surface modification, functionalization or hybridization with other nanomaterials and/or polymers for specific applications. Functionalization of inorganic nanoparticles with polymers and/or rationally designed molecules offers a pathway towards engineering responsive and multifunctional composite systems. Stimuli-responsive polymer materials respond in a dramatic way to very slight changes in their environment (stress, temperature, light, ionic strength, pH, humidity and electric or magnetic fields). So far, functional smart polymers are becoming increasingly straightforward to design and synthesize nanomaterials with a remarkable range of predictable responses and other properties. Additionally, the hybridization of NPs with stimuli responsive polymers control and stabilize their assembly, and in consequence, the symbiosis between both components (nanoparticles and wrapping polymers), can result in smart nanomaterials which combine, change or present novel properties from their individual systems. These materials are playing an increasingly relevant part in a wide range of applications, such as smart optical systems and devices, micro-electromechanical systems, coatings, biosensors and diagnostics. On the basis of the high interest within the scientific community, even when important research has been done along the last years on the polymer coating of NPs, the establishment of new protocols for their functionalization is still needed. This talk will highlight recent development in the area of multifunctional organic-inorganic hybrid nanostructures that are self-assembled from nanostructured building blocks, focusing on the improvement of nano-hybrids’ optical responses depending on the impact of pH and temperature external stimuli.

Biography:

Augusto Di Gianfrancesco has been employed at the Centro Sviluppo Materiali (CSM) since February 1983 until December 2014, as a Senior Metallurgist and Project Leader for High Temperature Materials. He was responsible for R&D activities on steels and superalloys for high temperature applications in power generation plants. He was also a member of Management Committee of EU Program COST 522-536, Co-founder of the European Creep Collaborative Committee (ECCC) and Co-founder of the Italian Working Group on Creep Resistant Materials. He is an author and co-author of more than 300 technical reports and more than 100 papers presented at national and international conferences. Currently, he is Materials and Technologies Consultant and Chairman of the ECCC. He is the Editor of the “Materials for ultra-supercritical and advanced ultra-supercritical power plants”, published by Elsevier in 2016

Abstract:

Higher process temperatures and pressures are mandatory to increase net efficiency and reduce CO₂ emissions. As consequence of these more severe operating conditions require better materials with higher demands for development, manufacturing and fabrication. This paper summarizes the current status of the art of the materials for ultra-supercritical coal fueled power plants and the trend for the development needed for the next generation called “advanced ultra-supercritical” targeting >50% efficiency, where nickel base superalloys will be necessary for the hottest part of the plant. This new generation of power plants will give an effort for the reduction of the CO₂ emission, because forecast confirm the coal will be the most relevant source for energy production at least for the next 30 years.

Biography:

Takashige Omatsu is currently serving as the Director at the Optical Society (OSA), a Deputy Editor of Optics Express, and a Director of Photonics Division, Japan Society of Applied Physics (JSAP). Furthermore, he has worked as a committee member in many international conferences. He was elected as an OSA fellow and a JSAP fellow. He has been working on structured materials fabrication based on optical vortex illumination. He has published over 200 journal and conference papers, and has attended over 100 invited presentations of international and national conferences.

Abstract:

Light induced surface reliefs on azo-polymer films have been intensely studied through mass transport arising from an optical gradient force, anisotropic photo-fluidity, and cis-trans photo-isomerization, and they provide us to develop optical devices, such as hologram, active waveguides and photonic circuits. The mass transport occurs typically to direct the azo-polymer from a bright region toward a dark region along the polarization direction of the light, thereby inhibiting a spiral surface relief formation in the azo-polymer by linearly polarized light illumination. Optical vortex, i.e. light with a helical wavefront, carries unique features, such as its annular intensity profile and orbital angular momentum, and it has been widely investigated in various applications, for instance, optical trapping and manipulation, optical telecommunications, and a super resolution microscope. Recently, we and our co-workers discovered, for the first time, that optical vortex enables the formation of a single-arm chiral surface relief in an azo-polymer with the help of the spin angular momentum assigned by the circular polarization. Such chiral surface reliefs have the potential to be utilized to develop new optical devices, including chiral metasurfaces and plasmonic holograms for identification of the chirality of chemical composites with high accuracy and sensitivity. In this presentation, we detail the chiral surface relief formation in the azo-polymer by optical vortex illumination, and we also address the physical mechanism of the chiral surface relief formation by utilizing an analytical formula for the optical radiation force induced in an isotropic and homogeneous material by irradiation with a continuous-wave optical vortex.

Recent Publications

1. Barada D, Juman G, Yoshida I, Miyamoto K, Kawata S, Ohno S, Omatsu T (2016) Constructive spin-orbital angular momentum coupling can twist materials to create spiral structures in optical vortex illumination. Applied Physics Letters 108: 051108.

2. Takahashi F, Miyamoto K, Hidai H, Yamane Y, Morita R, Omatsu T (2016) Picosecond optical vortex pulse illumination forms a monocrystalline silicon needle. Scientific Reports 6: 21738.

3. Takahashi F, Takizawa S, Hidai H, Miyamoto K, Morita R, Omatsu T (2016) Optical vortex pulse illumination to create chiral monocrystalline silicon nanostructures. Physica Status Solidi (a) 213: 1063-1068.

4. Watabe M, Juman G, Miyamoto K, Omatsu T (2014) Light induced conch-shaped relief in an azo-polymer film. Scientific Reports 4: 4281.

5. Toyoda K, Takahashi F, Takizawa S, Tokizane Y, Miyamoto K, Morita R, Omatsu T (2013) Transfer of light helicity to nanostructures. Physical Review Letters 110: 143603.

Biography:

Alexander M Korsunsky is experienced in engineering microscopy of materials systems and structures for optimization of design, durability and performance at the University of Oxford, UK. He leads the Centre for In-situ Processing Science (CIPS) at Research Complex, Harwell. He a Consultant at Rolls-Royce Corp. on matters of residual stress and structural integrity, and is an Editor-in-Chief of Materials & Design, a major Elsevier journal (2016 impact factor 3.997). He has done his Doctor of Philosophy (DPhil) from Merton College, Oxford, and undergraduate education in Theoretical Physics. He was a Junior Research Fellow at Fitzwilliam College, Cambridge, and Lecturer at Newcastle University.

Abstract:

Thermoplastic polyurethane (TPU) elastomers are applied in a variety of situations, from medical devices to sports equipment. The block co-polymer structure of these materials engenders nano-scale structural inhomogeneities, resulting in non-uniform strain fields that depend on the scale of consideration. In order to elucidate the nature of deformation in such materials, we focus our attention on the transition between the hard and soft regions that have been called "fuzzy interfaces". To obtain experimental insights into these deformation phenomena we used a range synchrotron X-ray methods ranging from imaging to small angle scattering (SAXS) to diffraction (WAXS). Subsequent analysis by finite element modeling (FEM) and fast Fourier transformation (FFT) allowed agreement to be achieved between predicted and observed scattering patterns, providing the explanation for the observed 'strain deficit' at the nano-scale.

Biography:

John O Roberts has been a Tutor at the Open University Science for 30 Years. He has worked at the Rutherford-Appleton Lab and CERN. He has been a freelance tutor of Math, Physics and Chemistry for many years. He is the author of book “Those infinities and the periodic table”.

Abstract:

The patterns of stable quantum states in the periodic table are inverted and extended to infinity in both directions to accommodate spatial variation relative to the nucleus. The upper end leads to a cut off point for white matter. The lower end represents quantum states in plasma. At 10^-15m to 10^-20m the interaction between weak strong and gravity forces results in suitable boundary conditions for the production of elementary particles. Chemical classification of the elements requires convergence of chemical properties and quantum states. By defining group number as the maximum number of electrons in any one shell, hydrogen and helium are moved to the first set of 2(1)² states first proposed by Janet. The atomic numbers are adjusted and mass number removed as it is an average of isotopes of each element produced in every supernova. This produces the Roberts Janet nuclear periodic table which proposes two zero states, a cut off and start point, of the electric field in attractive then repulsive modes. By symmetry of these fields energy states emerge in plasma with the counter intuitive property that the nearer the nucleus the greater the number of energy states. Fusion results and the consequential recycling implies a more rapid collapse than supernovae given sufficient energy density that could create an as yet unobserved interaction at 10^-50m to 10^-65m between the strong and gravity forces. String theory and extra dimensions may be required to explain such mechanisms and multiverses.

Biography:

Kimihisa Yamamoto has received his PhD degrees from Waseda University in Polymer Chemistry in 1990. He joined the Department of Chemistry at Keio University in 1997 as a Professor. Currently, he is a Professor in the Chemical Resources Laboratory, Tokyo Institute of Technology, since 2010. His present research interests are in developing supra-metallomolecules for nanosynthesizers involving nanoparticles, subnanoparticles and superatoms.

Abstract:

We show that tin chlorides, SnCl₂ and FeCl₃ complexes to the imines groups of a spherical polyphenyl-azomethine dendrimer in a stepwise fashion according to an electron gradient, with complexation in a more peripheral generation proceeding only after complexation in generations closer to the core has been completed. The metal-assembly in a discrete molecule can be converted to a size-regulated metal cluster with a size smaller than 1nm as a molecular reactor. Due to the well-defined number of metal clusters in the sub-nanometer size region, its property is much different from that of bulk or general metal nanoparticles. Dendrimers are highly branched organic macromolecules with successive layers or “generations” of branch units surrounding a central core. Organic inorganic hybrid versions have also been produced, by trapping metal ions or metal clusters within the voids of the dendrimers. Their unusual, tree-like topology endows these nanometer-sized macromolecules with a gradient in branch density from the interior to the exterior, which can be exploited to direct the transfer of charge and energy from the dendrimer periphery to its core. Here we show that tin ions, Sn²⁺, complex to the imines groups of a spherical poly phenyl azo- methane dendrimer in a stepwise fashion according to an electron gradient, with complexation in a more peripheral generation proceeding only after complexation in generations closer to the core has been completed. By attaching an electron-withdrawing group to the dendrimer core, we are able to change the complexation pattern, so that the core imines are complexed in the last. By further extending this strategy, it should be possible to control the number and location of metal ions incorporated into dendrimer structures, which can be used as tailored catalysts, building blocks, or fine-controlled clusters for advanced materials.

Biography:

Hiroyuki Aoki is a Senior Scientist in Materials and Life Science division, J-PARC Center, Japan Atomic Energy Agency. He obtained his degrees of BE, ME and PhD from Kyoto University in 1996, 1998 and 2001, respectively. He became an Assistant Professor of Department of Polymer Chemistry, Kyoto University in 2001 and was promoted to an Associate Professor in 2006. In 2016, he moved to J-PARC as a Senior Scientist. His research interests are focused on structure and dynamics of polymer materials at the single molecule scale. He was awarded with the Inoue Research Award for Young Scientist from Inoue Foundation for Science (2002), Young Scientist Lectureship Award (2008), SPSJ Award for the Outstanding Paper in Polymer Journal (2008), and SPSJ Science Award from the Society of Polymer Chemistry, Japan (2016)

Abstract:

Polymer materials have been widely used in various scenes of our daily life because the polymers show unique physical properties. The origin of the polymer materials is the large entropy of a single molecule, which has a long chain-like structure with a large molecular weight. Therefore, the conformation of the single polymer chain has been the key problem in polymer physics. However, because the single polymer chain, show great complexity in the structure and molecular motion due to its large degree of freedom for the molecular structure, it has been difficult to obtain the direct information on the single chain by the conventional experimental techniques. In this talk, the author will present the novel methodology to examine the structure and dynamics of the single chain in a polymer material. In a bulk polymer material, a polymer chain takes a random coil conformation expanded in three dimensions and entangled with the surrounding chains. In order to extract the information from a single chain, it should be labeled by a fluorescent moiety. However, the conventional fluorescence microscopy does not have the high resolution to observe the single polymer chain. Recent development of super-resolution microscopy allows the fluorescence imaging with the spatial resolution on the order of 10 nm. The author has introduced this technique for the structural analysis of polymer materials. The fluorescence labeling of poly(methyl methacrylate) chain with a photo-switchable rhodamine dye and the astigmatic detection optics enabled the three-dimensional analysis of the chain conformation. The super-resolution microscopy reveled the molecular behaviorin the macroscopic deformation process.

Recent Publications:

1. Aoki H, Mori K, Ito S (2012) Conformational analysis of single polymer chains in three dimensions by super-resolution fluorescence microscopy. Soft Matter 8: 4930-4935.

2. Ube T, Aoki H, Ito S, Horinaka J, Takigawa T (2012) Relaxation of single polymer chain in binary molecular weight blends observed by scanning near-field optical microscopy. Soft Matter 8: 5603-5611.

3. Ube T, Aoki H, Ito S, Horinaka J, Takigawa T, Masuda T (2011) Relaxation of single polymer chain in poly(methyl methacrylate) films under uniaxial extension observed by scanning near-field optical microscopy. Macromolecules 44: 4445-4451.

4. Aoki H, Takahashi T, Tamai Y, Sekine R, Aoki S, Tani K, Ito S (2009) Poly(methacrylate)s labeled by perylenediimide: Synthesis and applications in single chain detection studies. Polym. J. 41: 778-783.

5. Ube T, Aoki H, Ito S, Horinaka J, Takigawa T, Masuda T (2009) Affine deformation of single polymer chain in poly(methyl methacrylate) films under uniaxial extension observed by scanning near-field optical microscopy. Polymer 50: 3016-3021.

Biography:

Taeyoon Lee has his expertise in developing conductive fiber with high performances and fiber-based electronic devices for various applications such as wearable, stretchable electronics and smart textiles. He joined the School of Electronic and Electrical Engineering in Yonsei University as an Assistant Professor in 2007 and now he is an Associate Professor. He received his BS and MS from Yonsei University and his PhD from UIUC in 2004 in Materials Science. Before joining Yonsei University as an Assistant Professor, he had worked as a Senior Process Engineer at Intel for 2005-2007.

Abstract:

Recent studies on electronic textile (E-textile) where various electronic elements are fabricated into fabrics have attracted considerable attention for the advanced wearable and flexible devices. Especially, textile-based pressure sensor have been widely explored for a lot of applications such as detecting vital signals of patients, diagnostic and motion detection by embedding them in clothes. For the realization of the highly sensitive textile-based pressure sensors, various types of pressure sensors such as capacitive, piezoelectric, piezoresistive and optical types have been investigated. Among these various types of sensors, capacitive pressure sensors have advantages in terms of simple design and analysis of the devices, high sensitivity, excellent stability and low power consumption. However, since fabrication of the sensors with high performances is difficult due to limitations of techniques and materials, it is very challenging to apply these capacitive fabric pressure sensors to advanced wearable devices. Here, we describe high-performance fiber-based pressure sensor, strain sensor, and multimodal sensor. For the development of the fiber-based sensors, a highly stretchable conductive fiber, which effectively overcomes the limitations of previous stretchable conductive fibers, was fabricated by combining metal nanoparticles and bio-inspired elastomeric fibers. The conductive fiber exhibits an excellent conductivity of 20.940 S/cm, superb stretchability of 450%, and high stability over 10,000 cycles. By using the conductive fiber, various fiber-based mechanical sensors such as a pressure sensor, strain sensor, and multimodal sensors were successfully fabricated. The fiber-based sensors have an unprecedented performance and can be easily integrated into fabrics, gloves, and clothes using a simple sewing method.

Biography:

Atsushi Kubo received his Doctorate degree in Mechanical Engineering from the University of Tokyo in 2015. His research interest is in a wide range of the computational simulation and modeling (mainly at the atomistic level) for the structural and functional materials, including semiconducting materials, ferroelectric materials, polymers, etc. In his current work at the Institute of Industrial Science, The University of Tokyo, he is investigating the mechanical properties of the structural polymers based on the atomistic- and macroscopic-level approaches.

Abstract:

Crack propagation in rubber materials has been intensively investigated because it is one of fundamental processes of failure in rubber materials and is strongly related to the lifetime of rubber products. Some experiments have observed dynamic crack propagation in stretched rubber sheets and reported an interesting phenomenon called the "velocity mode transition". The mode transition is an abrupt change of tendency in the relationship between the crack propagation velocity and the tearing energy (or the loaded strain), as schematically shown in Fig. 1. There are two regions below and above a certain transition point, which are referred to as the "slow mode" and the "fast mode", respectively. According to the experiments, the crack velocity exhibits a nearly discontinuous change by more than two orders of magnitude at the transition point. While the behavior of a propagating crack at the fast mode can be explained theoretically, the mechanism of the mode transition phenomenon has been still unclear despite its importance. Furthermore, no numerical simulation has been established to reproduce the transition phenomenon thus far. In this talk, we present a series of analyses based on the finite element method (FEM) for purpose of revealing the mechanism of the mode transition phenomenon. We carried out FEM simulations of the pure-shear test to mimic a precedent experiment and obtained the relationship between the loaded strain and the crack propagation velocity. The material model consists of the hyper elasticity and viscosity, which were determined to reproduce the mechanical properties of a filled elastomer. As a result, the mode transition phenomenon was reproduced by the present FEM analyses, which revealed that the mode transition correlates to the viscoelastic behavior with a wide range of time scale. The mechanism of the transition phenomenon was well explained through a characteristic mechanical behavior at the crack tip.

Biography:

Stefano L. Oscurato graduated as MSc in Physics at University of Naples "Federico II" Italy, with a Master's dissertation about the development of a holografic scanning microscopy techique. He is doing his doctoral studies at University of Naples at the nano-optics laboratory, supervised by Prof. Pasqualino Maddalena and Dr. Antonio Ambrosio. His PhD work is about the use of light-driven mass migration in azobenzene-cointaing materials for application in photonics, wettability and adehision.

Abstract:

Inspired by nature, in the last years the role of the topography of superficial textures in determining surface functionalities is increasingly recognized and the fabrication of controlled tridimensional textures became a demanding point of material science because of the potential applications in many fields as photonics, functional and smart surfaces. Standard fabrication techniques, including photo-lithography, electron beam and focused ion beam lithography, self-assembly, soft lithography, etc., often require multi-step processes in order to realize 3D architectures and the fabricated geometries are rarely further tunable. However, the light-induced mass migration phenomenon arising in photo-responsive azo-benzene containing materials opens to new fabrication approaches. Under illumination, the azo-benzene molecules exhibit photo-isomerization trans-cis-trans cycles. This microscopic motion drives a reorganization of the host material, typically a polymer, in which the molecules are embedded, resulting in a macroscopic material displacement. This material motion is highly directional and occurs in the illuminating light polarization direction. Recently, our group proposed phenomenological models to deterministically predict the topography of the azo-surfaces resulting from light-surface interaction in different configurations. So the light-driven mass migration can be actually used to fabricate new classes of surface topographies, which can be even further modified once fabricated. Here, we demonstrate the potentiality of this technique by realizing tri-dimensional complex superficial patterns based either on spatially structured illumination light patterns or on reshaping of pre-patterned surface architectures. Spatially modulated intensity patterns are achieved in a versatile way by phase-modulating a laser beam through a computer controlled spatial light modulator, resulting in topography modulation of the azo-surfaces, even with high spatial resolution. On the other side, tri-dimensional architectures are obtained by reshaping pristine pre-patterned micron-posts in simple illumination condition. These resulting structures are proven to produce a change in the wetting behavior of the textured surface with a demonstrated controlled directional droplet spreading.

Biography:

Francis Opoku received his BSc in Chemistry (2010) and MPhil in Inorganic Chemistry (2014) from the Kwame Nkrumah University of Science and Technology, Ghana. He is now pursuing PhD degree in Chemistry under the supervision of Dr. Penny Poomani Govender, Dr. Krishna Kuben Govender and Dr. Cornelia Gertina Catharina Elizabeth van Sittert in the Department of Applied Chemistry, University of Johannesburg, South Africa. His research interests include the design of efficient semiconductor-based photocatalyst materials and their applications in water splitting as well as degradation of pollutants in wastewater/water resources.

Abstract:

Environmental pollution and energy exhaustion has received much interest both in scientific and industrial research fields. For this reason, tremendous efforts are made to design novel environmentally friendly non-polluting and sustainable energy storage photocatalysts for efficient solar energy harvesting and conversion. Semiconductor-based photocatalysis has received increasing attention in energy storage and environmental remediation process due to the abundantly solar energy. For this purpose, several heterostructures using BiVO₄, Ag₃PO₄, SrTiO₃ and WO₃ monolayers coupled with ZrO₂ nano-cluster are designed to examine their potential applications in energy storage and degradation of pollutants using density functional theory calculations for the first time. Moreover, the underlying mechanism, band edge positions, optical and electronic properties of the ZrO₂-basedheterostructures are evaluated. The results displayed that the calculated band gap of the heterostructures is reduced compared to the pure ZrO₂, which favors redshift absorption. A type-I band alignment was attained for the BiVO₄/ZrO₂, Ag₃PO₄/ZrO₂ and WO₃/ZrO₂ hetero-structures. More importantly, the type-II staggered band alignment formed in the SrTiO₃/ZrO₂ heterostructure restrained the charge recombination rate of the photoinduced carrier charges, as well as enhancing the photocatalytic activity. Our results display efficient charge separation and visible light response of the BiVO₄/ZrO₂, Ag₃PO₄/ZrO₂, WO₃/ZrO₂ and SrTiO₃/ZrO₂ heterostructures. In particular, suitable band alignment of SrTiO₃/ZrO₂ with enough driving forces for charge carrier transfer show overall water splitting and degradation of pollutant in which SrTiO₃ acted as the charge separation center. Thus, the SrTiO₃/ZrO₂ heterostructure emerges as a new type of ZrO₂-based photocatalyst for efficient solar energy applications. Furthermore, h⁺, HO^• and O₂^−• radicals played a major role in the photocatalysis process. Finally, possible charge separation and photocatalytic mechanisms of BiVO₄/ZrO₂, Ag₃PO₄/ZrO₂, WO₃/ZrO₂ and SrTiO₃/ZrO₂ heterostructures are proposed.

Recent Publications:

1. Boateng T K, Opoku F, Acquaah S O, Akoto O (2016) Groundwater quality assessment using statistical approach and water quality index in Ejisu-Juaben Municipality, Ghana. Environmental Earth Sciences 75:1-14.

2. Nkansah M A, Opoku F, Ackumey A A (2016) Risk assessment of mineral and heavy metal content of selected tea products from the Ghanaian market. Environ. Monit. Assess 188: 1-11.

3. Nkansah M A, Opoku F, Ephraim J H, Wemegah D D, Tetteh L P (2016) Characterization of beauty salon wastewater from Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, and its surrounding communities. Environ. Health Insights 10: 147.
4. Opoku F, Asare-Donkor N K, Adimado A A (2015) Quantum mechanical study of the kinetics, mechanisms and thermodynamics of the gas-phase decomposition of Pb[(iPr)2PSSe]2 single-source precursor. J. Organomet. Chem. 787:33-43.

5. Opoku F, Asare-Donkor N K, Adimado A A (2014) Theoretical study of the gas-phase decomposition of Pb[(C6H5)2PSSe]2 single-source precursor for the chemical vapor deposition of binary and ternary lead chalcogenides. Can. J. Chem. 93: 317-325.

Biography:

Hikaru Kobayashi received Doctor of Science in Chemistry from Kyoto University in 1984.  He was a Post-doctoral fellow at Physics department in University of Pennsylvania between 1984 and 1986, and then he started working at the Matsushita Electronics Company.  He became an Associate Professor of Faculty of Engineering Science, Osaka University in 1990, and moved to Institute of Scientific and Industrial Research of Osaka University as a Full Professor.  He has been performing researches on fabrication of Si nanopowder, its application to hydrogen generation material, anode material in Li ion batteries, and luminescent material.  He has also been studying material science related to crystalline Si solar cells, especially surface and interface control to improve conversion efficiencies.

Abstract:

Although Si bulk doesn’t strongly react with water, Si nanopowder reacts with it when its size is less than ~20 nm, leading to generation of hydrogen.  In previous literature, reactions of Si nanopowder with strong alkaline solutions have been investigated to achieve high hydrogen generation rates for application to e.g., fuel cells.  In the present study, we have aimed at generation of hydrogen in internal conditions.  Hydrogen generated in the body, especially in bowels, is effectively absorbed, is circulated, and reacts with hydroxyl radicals which cause various diseases such as cancer, Alzheimer’s disease, Parkinson’s disease, etc.  Figure 1 shows the concentration of hydrogen generated by the reaction of 1 g Si nanopowder with water in the neutral pH region.  Hydrogen was generated even with ultrapure water, but the generation rate was very low.  The hydrogen generation rate greatly increased with pH while pH didn’t change after the hydrogen generation reaction.  Therefore, the reaction schemes are written as:

Si+2OH^-→SiO₂+H₂+2e,     (1)                                        

2H₂O+2e→H₂+2OH^-.         (2)

In the initial reaction, Si reacts with OH^－ ions to generate hydrogen, SiO₂, and electrons most probably in the SiO₂ conduction band.  In the subsequent reaction, generated electrons are accepted by water molecules, resulting in formation of hydrogen and OH^－ ions.  Reaction (1) is the rate-determining step, and thus, the reaction rate greatly increases with pH. The above result indicates that when Si nanopowder is taken, it doesn’t react in stomach under acidic conditions due to gastric acid, but reacts with water in bowels in alkaline conditions because of pancreatic juice. We have performed hydrogen generation experiments under conditions similar to bowels, i.e., pH 8.3 and 36ºC.  In this case, more than 300 mL hydrogen was generated from 1g Si for 20 h.  This hydrogen volume corresponds to that contained in more than 17 L saturated hydrogen-rich water.

Recent Publications:

1. Imamura K, Irishika D, Kobayashi H, (2017) Mechanism of ultra-low reflectivity for nanocrystalline Si/crystalline Si structure formed by surface structure chemical transfer method. J. Appl. Phys. 121: 013107-1-5.

2. Imamura K, Kimura K, Fujie S, Kobayashi H, (2016) Hydrogen generation from water using Si nanopowder fabricated from Si swarf. J. Nanopart. Res. 18: 116-1-7.

3. Matsumoto T, Maeda M, Kobayashi H (2016) Photoluminescence enhancement of adsorbed species on Si. Nanoscale Res. Lett. 11: 7-1-6.

4. Matsumoto T, Maeda M, Furukawa J, Kim W B, Kobayashi H (2014) Si nanoparticles fabricated from Si swarf by photochemical method. J. Nanopart. Res. 16: 2240-1-7.

Biography:

Marzia Quaglio is a Researcher at the Center for Space Human Robotics of the Italian Institute of Technology (IIT). She graduated in Materials Engineering at the Politecnico di Torino and received her PhD in Electronic Devices from the Politecnico di Torino. Her research activity started with a main focus on MEMS/NEMS processing for the fabrication of life-science devices. She collaborated with Professor Cerrina at the University of Wisconsin, Madison for her research work. In 2009, she joined IIT contributing in the start-up of the Center for Space Human Robotics. She is currently involved in the Reactors and Processes division, with interest in the development of new electrode materials and catalysts for (bio)-electrochemical systems for CO₂ conversion.

Abstract:

This work is focused on the development of N-doped carbon nanofibers (N-CNFs) as catalyst for the oxygen reduction reaction (ORR). In devices for energy storage and production, as microbial fuel cells and li-air batteries, oxygen can be used as the terminal electron acceptor. The overall efficiency of these devices is limited by the low kinetics of the ORR. A catalyst layer must be used, to enhance the direct ORR, ensuring a number of electrons as close as possible to the ideal value of 4. Platinum is currently the best performing catalyst, however its scarcity, limited durability and high-cost, have made necessary to identify efficient substitutes. In this view nanomaterials can play a crucial role for further improvement in this area of catalysis. The development of nonprecious materials as alternative catalysts is among the pursued strategies. Nanostructured non-metal carbon-based materials, especially doped with heteroatoms like nitrogen, have established among the most promising noble metal free alternatives. In this work focus is given to the optimization of N-CNFs, especially in terms of their content of graphitic, pyrrolic and pyridinic nitrogen defects, as well as their high surface area. N-CNFs have been prepared by electrospinning, starting from a polymeric solution of polyacrylonitrile in N,N-dimethylformamide. As fabricated nanofibers were stabilized at 280ºC in air and then thermally treated up to 900ºC under inert atmosphere. X-ray photoelectron spectroscopy confirmed a high content of graphitic nitrogen and a proper amount of pyridinic one in CNFs, leading thus to improve ORR performances. Good electrochemical properties of the samples were established by rotating ring disk electrode (RRDE). An electron transfer number of 3.9 has been obtained for the N-CNFs processed at the higher temperature.

Recent Publications:

1. Delmondo L, Salvador G P, Muñoz-Tabares J A, Sacco A, Garino, N, Castellino M, Gerosa M, Massaglia G, Chiodoni A, Quaglio M (2016) Nanostructured Mn_xO_y for oxygen reduction reaction (ORR) catalysts. Applied Surface Science 388: 631-639.

2. Garino N, Sacco A, Castellino M, Muñoz-Tabares J A, Chiodoni A, Agostino V, Margaria V, Gerosa M, Massaglia G, Quaglio M (2016) Microwave-assisted synthesis of reduced graphene oxide/SnO₂ nanocomposite for oxygen reduction reaction in microbial fuel cells. ACS Applied Materials & Interfaces 8: 4633.

Biography:

Mineo Hiramatsu is a Full Professor in the Department of Electrical and Electronic Engineering and the Director of Nanocarbon Research Center, Meijo University, Japan. He also serves as the Director of Research Institute, Meijo University. He served as the Director of the Japan Society of Applied Physics. His main fields of research are plasma diagnostics and plasma processing for the synthesis of thin films and nanostructured materials. He is the author of more than 100 scientific papers and patents on plasma processes for materials science. He is a member of organizing and scientific committees of international conferences on plasma chemistry and plasma processing: International Conference on Reactive Plasmas, International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials, International Symposium on Dry Process, International Conference on Advanced Nanomaterials, THERMEC, International Conference on Processing and Manufacturing of Advanced Materials.

Abstract:

Graphene is a promising material for future electronic applications due to its outstanding properties. Planar graphene films have been synthesized using mechanical exfoliation from HOPG and chemical vapor deposition (CVD) on metals such as Ni and Cu. On the other hand, plasma-enhanced CVD (PECVD) is among the early methods to synthesize vertically standing few-layer graphenes or carbon nano walls (CNWs). CNWs are few-layer graphenes standing vertically on a substrate to form a self-supported network of wall structures. The maze-like architecture of CNWs with large-surface-area graphene planes would be useful as electrodes for energy storage devices, electrochemical and biosensors, and scaffold for cell culturing. We have investigated the synthesis of CNWs and planar few-layer graphene using PECVD with controlling the ion flux incident on the substrate and surface pretreatment. In the present study, CNW growth using inductively coupled plasma (ICP) enhanced CVD is featured, since the ICP CVD system has advantages of simple design and scalability to large area growth. Figures 1(a) and (b) show SEM images of CNWs grown using ICP. Typical Raman spectra of CNWs and planar few-layer graphene are shown in Fig.1(c). For the growth of CNWs, ion bombardment on the substrate surface would play an important role in nucleation by creating active sites for neutral radical bonding, resulting in the formation of vertical nanographene even in the case using Ni and Cu as substrates. On the other hand, by reducing the ion flux or ion energy incident on the substrate, it became possible to suppress the nucleation of CNWs under the typical plasma condition for the growth of CNWs. We report the current status of the control of the CNW structures during the growth processes as well as post treatment to be used as platform of the electrochemical and bio applications.

Recent Publications:

1. Hiramatsu M, Kondo H, Hori M (2015) Nanoplatform based on vertical nanographene, graphene - New trends and developments. Ed. InTech: 145-178.

2. Hiramatsu M, Shiji K, Amano H, Hori M (2004) Fabrication of vertically aligned carbon nanowalls using capacitively coupled plasma-enhanced CVD assisted by hydrogen radical injection. Applied Physics Letters 84: 4708-4710.

3. Watanabe H, Kondo H, Okamoto Y, Hiramatsu M, Sekine M, Baba Y, Hori M (2014) Carbon nanowall scaffold to control culturing of cervical cancer cells. Applied Physics Letters 105: 244105.

4. Cho H J, Kondo H, Ishikawa K, Sekine M, Hiramatsu M, Hori M (2014) Density control of carbon nanowalls grown by CH₄/H₂ plasma and their electrical properties. Carbon 68: 380-388.

Biography:

Nekane Guarrotxena has done her PhD from the University of Complutense, Madrid-Spain and Post-doctoral Research from the Ecole Nationale Supérieure of Arts and Crafts (ENSAM), Paris-France and the University of Science II, Montpellier-France. She was the Vice-Director of the Institute of Polymer Science and Technology (ICTP-CSIC) (2001-2005) and Visiting Professor at the University of California, Santa Barbara-USA and the CaSTL at University of California, Irvine-USA (2008-2011). She is currently a Research Scientist at ICTP-CSIC (Spain), Editorial Board Member of some Materials Science and Chemistry journals and External Expertise Consultant on I+D+I Management Policy for national and international agencies. Her research interest focuses on the synthesis and assembly of hybrid nanomaterials, nanoplasmonics, and their uses in nano biotechnology applications (bioimaging, drug delivery, therapy and biosensing).

Abstract:

Rational assembly of metal nanoparticles (NPs) is relevant for effective exploitation of structure-dependent material properties and for making nanostructured materials with specific activity in optical (sensing) and electronic (nanodevices) applications. Despite relevant improvements on solid surfaces, fabrication and organization of narrow size- and shape distributions of NPs in solution remain a challenge. One of the most successful approaches for their fabrication involves use of colloids and well-established thiolate adsorption chemistry. In this approach, dithiols can be used to bring together metal nanoparticles (Ag and Au) by virtue of metallic NP-sulfur bond formation. The general difficulty in this controlling aggregation methodology is that, the linking process is random by nature and is difficult to control, generating a statistical distribution of aggregated NPs. An alternative to non-ideal NPs assembly would be an effective post-synthetic purification method. In this presentation, we will focus on this approach for collecting efficient and intense optical SERS active nanostructure for novel applications from NP-assemblies pool. The contribution of the thiolated linker’s nature on the final scattering response from the engineered assemblies will be also considered.

Biography:

Bingsuo Zou has done his Doctorate degree from Jilin University in 1991, Post-doctoral studies from Nankai University and joined as a Faculty member at Institute of Physics, CAS in 1994. He has visited National University of Singapore and Georgia Tech as a Visiting Scholar in 1996-1999. In 2005, he joined the Huna University as a Faculty member in the School of Physics and Microelectronics. In 2006, he was nominated and enrolled as a Changjiang Scholar of MOE. In 2009, he joined the faculty of BIT (Beijing Institute of Technology) as the Dean of School of MSE. Currently, he is the Director of Micro Nano Technology Center of BIT.

Abstract:

Optical properties of diluted magnetic semiconductor (DMS) are not well understood so far, especially relationship to their ferromagnetism. Here we prepared Mn ion doped ZnO, CdS and ZnSe nanostructures by CVD method, studied their optical properties via microphotoluminescence techniques, found many very interesting properties, which are all related to the exciton magnetic polaron (EMP), itinerant or partially itinerant, their energy levels go well with the ab initio calculations. In ZnO:Mn nanowires, the EMP can show up with free exciton together for very diluted doping (<0.001%), this EMP can form condensate to produce single mode lasing line at fs pulse excitation along with the disappearing of free excitons, which indicate a condensation of EMP. With a little bit large amount of Mn doping, the nanowire show EMP lasing mode with background at fs laser pulse excitation, but at even high power, some electron-hole plasma induced lasing modes could be observed due to the carrier effect. The time-delayed photoluminescence by ns laser pulse are also studied, only free EMP and localized EMP (d-d transition) show up in the emission spectra, we gave the clear assignments for all the d-d transitions of Mn in ZnO, which have been argued for a long time. It is more interesting that these d-d transitions exhibit clear enhanced coherent relaxation behaviors with increasing excitation power, like that by free excitons, even couple with LO phonons, and show a collective spin-dependent coherent radiation, which may be used for quantum modulation applications. We also observed the Mn-O-Mn cluster peak in the long wavelength range, which may be related to the ferromagnetic properties. In CdS:Mn nanowires, we found many peaks longer than the single Mn ion emission band (575nm) when increasing the Mn concentration, we used a simple hydrogen-like cloud theoretical model to describe them well, in this model, the Mn-S-Mn-Segregate with variable Mn ion number and their ferromagnetic coupling are considered. The SQUID detection proved the ferromagnetic behavior of the aggregate, and MFM imaging indicated its cluster nature in a microbelt or nanowire. Ab initio calculation results also support our assignments. The aggregation of Mn ion in II-VI semiconductor microstructures can produce ferromagnetic and PL emission at the same time.

Biography:

Marco Laurenti has done his MSc degree in Physical Engineering from the Politecnico di Torino in 2011. In 2015, he received his PhD in Physics at the Politecnico di Torino, in collaboration with the Italian Institute of Technology, Center for Space Human Robotics. He has done his PhD thesis on the deposition and characterization of pristine and doped piezoelectric ZnO thin films by sputtering, for sensing and energy harvesting applications. He is currently working as Post-doctorate at the Politecnico di Torino. His activities and research interests include the CVD growth of monolayer graphene for the fabrication of nanoporous membranes for water desalination and oil/water separation.

Abstract:

Nowadays, membrane technology often relies on the use of porous substrates to selectively separate specific compounds from fluids. To improve the separation efficiency and reduce the operating costs, new generation membranes are highly desirable and for numerous applications, like water desalination, oil/water separation as for the isolation and/or extraction of specific biological moieties. A possible solution is to reduce the thickness of the membrane as much as possible. Thanks to their one-atomic-layer thickness coupled with excellent mechanical strength and chemical stability, graphene-based membranes recently gained lots of attention. Several studies showed that graphene with stand strong pressure regimes (up to 57 MPa), while excellent water permeability, high flow rates and promising salt rejection are possible if controlled nanopores are opened within the graphene layer. The present study deals with the fabrication of nanoporous graphene membranes based on CVD-grown monolayer graphene, and porous polycarbonate membranes (PCTE)as supports. Graphene was grown on Cu foils by thermally-activated low-pressure chemical vapor deposition and transferred onto the PCTE supports by following a simple and fast direct transfer procedure. The quality of graphene on Cu foils and PCTE membranes was checked by Raman spectroscopy. After the transfer, FESEM analyses highlighted the good graphene coverage of PCTE, and pointed out the presence of intrinsic graphene defects at the nanoscale. Finally, the water flux and methylene blue (MB) filtration across the nanoporous graphene/PCTE membranes were evaluated in a dead-end cell filtration apparatus. In conclusion, Raman spectroscopy and FESEM analyses confirmed the good quality of monolayer graphene, before and after the transfer process. The presence of intrinsic defects was also observed, allowing for water permeability and molecular selectivity to be obtained. Accordingly, our preliminary results showed that water permeability together with around 90% MB rejection could be obtained for a convenient choice of the polymeric support together with the presence of intrinsic nanopores.

Biography:

S E Stanca has her expertise in electrochemical and optical nanosensors achieved during her research activity at the EPFL Lausanne (Swiss Confederation Fellow), UCD Dublin (Marie-Curie-Fellow), UKJ Jena (Marie-Curie-Fellow), University Babes-Bolyai Cluj-Napoca, Research Centre Karlsruhe and IPHT Jena (DAAD Fellow). She is currently a Scientist at the Leibniz Institute of Photonic Technology Jena.

Abstract:

An ongoing objective in the field of nanotechnology is to create specific nanostructures by precisely engineering their physico-chemical properties such as size, shape, charge, aqua-phobicity/philicity and chemical reactivity. The distinctive properties of noble metal perpetually inspire people, leading to new and unpredictable applications. Several scientific efforts were already concentrated to achieve structures of noble metal with new optical values while preserving the electrical and thermal conductivity. In this context, the chemical and electrochemical synthesis of the sensing active metallic colloids in aqueous and non-aqueous media, and also their characterization will be detailed. The obtained noble metal blacks exhibit high purity and are described by a broad absorbance and low reflectance in the ultra violet, visible and in the infrared domain from 200 nm to 20000 nm. X-ray analysis established the purity and crystalline nature. The electron micrographs indicate that the nanostructures consist of crystals that interconnect to form porous assemblies. Particularly, it will be shown how the platinum black thin layer, electrochemically deposited on different metallic and semi-conductive substrates is influenced by the substrate materials. The characteristics of high conductivity, low reflection coupled with high specific surface could confer to the noble metal blacks’ value in catalysis and in electronics, predominantly in optical sensors.

Recent Publications:

1. Stanca S E, Hänschke F, Ihring A, Zieger G, Dellith J, Kessler E, Meyer H G (2017) Chemical and electrochemical synthesis of platinum black. Scientific Reports 7: 1074.

2. Stanca S E, Fritzsche W, Dellith J, Undisz A, Deckert V, Krafft C, Popp J (2015) Aqueous Black colloids of reticular nanostructured gold. Scientific Reports 5: 7899.

Biography:

Ravindra Reddy Chowreddy has received MSc in Chemistry from Bangalore University, Bangalore, India in 1999 and PhD in Applied Sciences from Visvesvaraya Technological University, India in 2006. He has 4 years of Post-doctoral research experience from University of Waterloo, Canada. Currently, he is working as a Senior Researcher at Norner AS, an industrial R&D services provider in the field of plastics in Norway. His research areas of interest include polymer nanocomposites, bioplastics from the renewable sources and food co-streams.

Abstract:

Polymer nanocomposites (PNCs) containing organic and inorganic nano-fillers have attracted great interest from both academia and industry due to their unique characteristics. PNCs exhibit superior mechanical properties, lower permeability for gases, improved flame retardancy, better thermal stability, improved chemical resistance, and enhanced thermal and electrical conductivity. In the present study, recycled poly(ethylene terephthalate) (PET) nanocomposites containing multi-wall carbon nanotubes (CNTs) were prepared through melt compounding via masterbatch dilution method. The masterbatch and the nanocomposites were processed in a twin-screw extruder. The resulting PET-CNT nanocomposites were characterized for rheological, thermal, mechanical and morphological properties. Incorporation of CNTs into recycled PET at reasonably lower concentration significantly increases the viscosity. The storage modulus and loss modulus of nanocomposites was also increased with CNTs loading and which was more pronounced at lower frequencies. The incorporated CNTs in recycled PET increase the degree of crystallinity and crystallization temperature through heterogeneous nucleation. Thermal stability and glass transition temperature of PET-CNT nanocomposites was slightly higher than the reference recycled PET. The tensile properties of PET-CNT nanocomposites increased even at low concentrations of CNTs. Morphological investigation through scanning electron microscopy indicated homogeneous dispersion of CNTs at lower concentrations. At higher concentrations, the CNTs tend to agglomerate due to nanotube-nanotube interactions.

Biography:

Marta Prada is a Theoretical Physicist at the Institute for Theoretical Physics. She obtained her PhD degree in 2006 from the University of Leeds. She did her first Post-doctoral degree from the University of Purdue with Professor Klimeck, on the topic of large scale nano-electronic simulators, and then moved as a Lecturer and Research Assistant to the University of Madison-Wisconsin, in the Quantum Computing Group. Currently, she works at the University of Hamburg, Germany since 2013 and is involved in a number of projects: correlations in ultra-cold atom systems, effects of interactions in topological systems, bulk band-edge correspondence in graphene-like systems and nano-electromechanical systems.

Abstract:

In the early 80’s, Berry discovered an intriguing, non-integrable phase depending only on the geometry of the parametric space. This phase, which had been overlooked for decades, provided a deep insight on the geometric structure of quantum mechanics, resulting in various observable effects. The concept of the Berry phase is a central unifying concept in quantum mechanics, shedding light onto a broad range of phenomena such as the Aharonov-Bohm effect, the quantum and the anomalous Hall effect, etc. Moreover, geometric or Berry phases nowadays represent the most robust resource for storing and processing quantum information. In this work, we derive the general form of the non-trivial geometric phase resulting from the unique combination of point group and time reversal symmetries. This phase arises e.g. when a magnetic adatom is adsorbed on a non- magnetic C_n symmetric crystal surface, where n denotes the fold of the principal axis. This phase dictates non-trivial spin dynamics, bearing enhanced lifetimes of prepared states. In addition, the energetic ordering and the relevant quantum numbers of the eigenstates are entirely determined by this quantity. Moreover, this phase allows to conveniently predict the protection mechanism of any prepared state, shedding light onto a large number of experiments and allowing a classification scheme. Owing to its robustness this geometric phase also has great relevance for a large number of applications in quantum computing, where topologically protected states bearing long relaxation times are highly desired.

Recent Publications:

1. Prada M (2017) The geometric phase of Zn- and T-symmetric nanomagnets as a classification toolkit. Nature Sci. Rep. 7: 46614.

Biography:

Angelica Chiodoni is Researcher at the Center for Sustainable Future Technologies of the Istituto Italiano di Tecnologia (IIT). She graduated in Materials Science at the Universita’  degli Studi di Torino and received her Ph.D. in Physics at the Politecnico di Torino. Her research activity is mainly focused on the use of the electron microscopy as a powerful tool for material characterizations. She is the coordinator of the Electron Microscopy facility of the Center, including a Dual Beam and a 200 KV Transmission Electron Microscope. She is currently involved in the Advanced Materials Division, with interest on the development of catalysts for the photo/electrochemical CO2 reduction and conversion.

Abstract:

In   the  framework  of  the  growing  concerns about   global warming, the development of new and clean energy resources represents one of the major scientific challenges.  In particular, in fuel cells and  metal-air batteries, the electrochemical Oxygen Reduction Reaction (ORR) occurring at the cathode is one of the key limits for their further development and requires electrocatalysts to increase the reaction efficiency. Manganese oxides are among the most considered non-precious metal-based  catalysts  due  to  their low  cost, relatively high abundance,  low  environmental impact  and  considerable electrocatalytic activity. In this work we present nanostructured manganese oxides in the form of xerogels (obtained by means of the sol-gel plus freeze- drying techniques) and in the form of nanofibers (obtained by means of  the  electrospinning  technique) as  catalysts  for  the Oxygen  Reduction  Reaction.  They  were  synthesized by employing  manganese   acetate   as  the  Mn source  and   by employing environmental friendly  (water  is  the  used  solvent) templating agents, such as agar  and  polyethylene oxide, for xerogels and nanofibers respectively. To investigate  the  oxidation  process forming  the  manganese oxides species,  structural and  morphological characterizations as  in-situ X-ray diffraction, field  emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were performed on both the nanostructures. The obtained materials were composed by Mn₃O₄, Mn₂O₃, or a mix of both, depending on the calcination temperature. The catalytic  performance of the two nanostructured catalysts were characterized by means of the rotating ring disk electrode technique by  using 4-electrodes  measurements. Both xerogels and  nanofibers  showed good  performances  for  the  oxygen reduction reaction, with n values between 3.5 and 3.7, meaning a predominant 4-electrons reduction pathway.