# XVII B-MRS

The Brazilian Materials Research Society (B-MRS) and the Organizing Committee of the XVII Brazilian MRS meeting has invited the worldwide community of materials research to attend the 2018 meeting, was held at the Praiamar Natal Hotel in Natal-RN, from September 16th to 20th, 2018.

### Memorial Lecture

#### Fernando Galembeck

Brazil

###### Materials for a Better Future

### Fernando Galembeck

Human development has always relied on the creation, development and transformation of materials to make tools, equipment, buildings and weapons, from the Stone Age to the fourth industrial revolution. Today, new materials development and the production of common materials are threatened by the growing scarcity of raw materials, suggesting the concentration of efforts to increase usage of inputs from renewable or abundant sources, including biomass. The use of agricultural land for energy and raw materials production has been challenged, but real examples from Brazil and Ethiopia show the synergy in the production of food, energy and raw materials production, as opposed to the presumed competition. In the past 30 years, the author concentrated on two topics: i) the making of nanocomposites, especially those based on natural rubber and cellulose and ii) the role of electrostatics in materials structure, properties and applications. Results are new, “green” processes for making functional materials, e.g. high-performance conductive films and monoliths based on graphite, cellulose and rubber that are being developed to make circuit boards, heaters, supercapacitors and microfluidic/sensing devices. The work on electrostatics led to a new understanding of materials electrostatic charging and to new approaches for energy scavenging, biomass separation and real-time fatigue monitoring.

## Fernando Galembeck

Fernando Galembeck is a physical and materials chemist that challenged widespread scientific paradigms and introduced new methodology, models and solutions to important scientific problems. Many of his discoveries translated into industrial products and processes creating jobs and income for many persons, conferring sustainability to scientific activity and supporting his activities as a professor, consultant to companies and governments, planner and research manager. Since 1999, he presented and verified new chemical hypotheses to explain electrostatic phenomena and tribology. These two areas did not receive much attention during the 20th century, largely due to widespread but unproven assumptions. The contributions of his group were recognized by four awards from the Electrostatic Society of America, to him and his students, since 2011. His groundbreaking work on polymer surfaces and on the fractionation of polymer colloids allowed him to contribute to the elucidation of the "mystery of natural rubber" by showing that it is a natural nanocomposite held together by electrostatic adhesion, a hitherto unsuspected feature. His contributions were largely supported by the extensive use of electronic (transmission and scanning) and scanning (especially Kelvin probe and electric force) microscopy techniques and by his contributions to methodology, introducing molecular mapping and practicing correlative microscopy well before this designation was introduced. He also introduced new separation techniques and functional materials, using new concepts and creating new industrial products. Current work concentrates on i) the development of non-metallic, high-performance conductive solids based on graphite, cellulose and other polymers, made through scalable and "green" processes and ii) chemical mechanisms of electrostatic charging. Detailed related information is in a Personnal Account recently published in The Chemical Record (published by the Chemical Society of Japan) and in the book Chemical Electrostatics (Springer, Cham, 2017).

### Plenary Lectures

#### Bernhard Keimer

Max-Planck-Institute for Solid State Research, Germany

###### Spectroscopy of collective excitations in oxide heterostructures

### Bernhard Keimer

A grand challenge in the field of correlated-electron physics is the transition from conceptual understanding of collective ordering phenomena to their control and design. We will outline recent results of an experimental program designed to meet this challenge through the synthesis and characterization of metal-oxide heterostructures and superlattices. We will emphasize copper and nickel oxides, where various instabilities such as superconductivity and complex magnetism appear in the vicinity of correlation-driven metal-insulator transitions. We will show how polarized photon-based methods such as resonant inelastic x-ray scattering and Raman scattering can be used to obtain a comprehensive description of collective excitations in these systems, thus obtaining new insights into the origin of the instabilities. We then outline perspectives for control of the phase behavior of correlated electrons in these structures by modifying the occupation of transition metal d-orbitals, the dimensionality of the electron system, and the electron-phonon interaction.

## Bernhard Keimer

Bernhard Keimer obtained his physics education at the Technical University of Munich and at the Massachusetts Institute of Technology, where he received his Ph.D. degree in 1991. He spent a year as postdoctoral associate at MIT and seven years on the faculty of Princeton University, where he was appointed Full Professor in 1997. In 1998 he was appointed Director at the Max Planck Institute for Solid State Research, where he and his research group investigate quantum materials using spectroscopic methods.

#### Carlos F.O. Graeff

Laboratório de Novos Materiais e Dispositivos - Faculdade de Ciências UNESP, Brazil

###### Materials for the Optimization of Solar Energy Harvesting

### Carlos F.O. Graeff

Solar energy is a very promising source of renewable energy. For this reason, the scientific community is doing great efforts to improve the efficiency of photovoltaic (PV) devices and, at the same time, to reduce its costs and its environmental impact. Dye-sensitized solar cells (DSSC) represents one of the most studied PV technology, in the last 20 years, due to its low costs, facility of fabrication and efficiencies up to 13%. In this respect, our research group proposed novel techniques to reduce the DSSC’s costs substituting Pt counter electrodes (CEs) with efficient low-cost materials. Cobalt sulfide (CoS) is a p-type semiconductor with a high catalytic efficiency in the oxidation/reduction of I-/I - redox couple. CoS become very interesting for the preparation of efficient CEs for DSSCs. However, most techniques proposed so far in the literature for the deposition of CoS thin films, does not consider the large-scale applicability of the processes. For this reason, we focused on ink-based techniques, compatible with both screen-printing and ink jet deposition, widespread used in films electronics fabrication. These CEs were also applied in p-type DSSCs based on erythrosine-sensitized NiO with good results in terms of efficiency . However, due to the p-type nature of CoS, it shows photocurrent limitations when a more performant p-type sensitized was used on NiO photocathodes due to the depletion of the majority charge carriers (holes) at the interface with the electrolyte. The chemical precursor route has been applied also for the production of hematite nanoparticles for n-type photoanodes for a future application in tandem DSSCs. Along with the research on DSSCs, we also investigate perovskite-based solar cells (PSCs), which have reached efficiencies up to 23% just in a few years. We recently demonstrated that by using Nb2O5 as hole blocking layer hysteresis can be efficiently reduced, and the device becomes more stable. The third class of materials for solar energy conversion that we have investigated are organic semiconductors. Recently we have investigated the charge generation and transfer in cyanine dyes blends using light-induced electron spin resonance.

## Carlos F.O. Graeff

Vice-President for Research of UNESP since 2017. He received his Ph.D. in Physics from the State University of Campinas (UNICAMP) in 1994. After a post-doctorate at TU München as fellow of the Alexander von Humboldt Foundation, he joined the University of São Paulo (USP), Campus Ribeirão Preto, as Assistant (1996-1999) and Associate Professor (1999-2006). In 2006 he joined the State University of São Paulo (UNESP) as Full Professor. He is Principal Investigator of CEPID-FAPESP “Center for the Development of Functional Materials“, research fellow 1B from the Brazilian National Research Council (CNPq), associate editor of Solar Energy (Elsevier), member of IUPAC Subcommittee on Polymer Terminology, and a member of Academia de Ciências do Estado de São Paulo (ACIESP). Professor Graeff was a visiting researcher at several universities around the world for example: at the Max Plank Institut für Festkörperforschung (MPI-FKF), Germany, at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland, and at Beijing Jiatong University (BJU), China. Former member of FAPESP Engineering Panel (2016-2017), Coordinator of the Materials Science Division in CAPES-Ministry of Education (2009-2014), Scientific Director of SBPMat (Brazilian-MRS, 2012-2014) and President of Clube Humboldt do Brasil (2011-2013). His field of interest is Materials Science, more specifically electronic magnetic resonance, biomaterials, organic semiconductors and electronic devices (solar cells and thin film transistors). He has a strong interest in nurturing scientific talent and supervised more than 45 Masters and PhD students as well as Postdocs. He has published more than 160 articles and holds several patents.

#### Christian Polak

Vacuumschmelze GmbH & Co. KG, Hanau, Germany

###### Soft Magnetic Nanocrystalline Materials for Inductors and Shielding Applications – Optimized for higher Frequencies

### Christian Polak

In recent times miniaturization and energy conservation of electronic devices have been demanded more intensively. There is the need for less environmental loads and accordingly for miniaturization a higher frequency and a smaller thickness have been demanded. Among metallic soft magnetic materials, amorphous and nanocrystalline alloys are the most promising candidates for high frequency applications. These relatively new materials developed during the last decades are meanwhile successfully applied in high grade magnetic cores for inductors. We will survey characteristic features of nanocrystalline alloys particularly relevant for inductor and shielding applications at higher frequencies. In particular we will discuss the optimization of the high frequency properties by applying new annealing and processing technologies. As an example, we will discuss nanocrystalline materials with huge anisotropy. Tape wound cores were produced using this nanocrystalline ribbons with linear hysteresis loops and particularly low DC permeability down to µDC = 100. In the cores of these inductive components highly non-uniform field distributions can occur, depending on the design. Thus, for conventional cores with homogeneous permeability distribution a noticeable degradation of component properties can be observed. This work will show new tape wound cores in which a designed permeability distribution is used in order to avoid the above mentioned issues. On the other hand, we will discuss inductances made of planar sheets used in inductive wireless power transmission systems. Nanocrystalline soft-magnetic shielding material is used to avoid lossy eddy currents being induced in electrically conducting components like batteries or ground layers of electronic circuits.

## Christian Polak

Studied technical physics at the Technical University in Vienna (Austria), where he received his Ph.D. degree. The thesis work was based on investigations of amorphous materials and opened the relationship to the company Vacuumschmelze as a manufacturer of soft-magnetic materials. In the year 1993, he joined Vacuumschmelze and since that time he has been continuously responsible for research and development. Currently he is the head of the research department for rapid solidification technology. Main tasks of investigations are designing new amorphous and nanocrystalline materials, advancement of casting technology and developing new heat treatment technologies for tailoring application orientated hysteresis properties.

#### Heinz von Seggern

Technical University of Darmstadt, Germany

###### Organic polymers: from electret microphones to energy harvesters

### Heinz von Seggern

Electrostatics is considered to be an old-fashioned science. However, understanding of dielectric properties has always resulted in amazing applications. On a journey starting with the invention of the electret foil microphone by Sessler and West in 1962 [1] and the discovery of PVDF (Polyvinylidenedifluoride) by Kawai [2] as piezo- and ferroelectric material it will be shown that the continuous need for improvement of the materials has led to new poling techniques, as well as techniques that allow for a deeper inside into charge transport and charge storage. As a result thin films of Teflon FEP (fluoroethylenepropylene) and Teflon PTFE (polytertrafluoroethylene) are recognized as best storage and insulating polymers up today. In 1989 a new approach for ferroelectric polymers has been introduced by VTT Technical Research Center, Finland, which utilizes charging of nonpolar, however, porous polypropylene (PP) to fabricate piezoelectric materials with high piezoelectric coefficients by electrical breakdown in the air filled pores. Due to poor thermal charge stability of PP, search for new materials and structures continues. Therefore it is not surprising that FEP and PTFE are reentering the scene. The latest development are fusion-bonded FEP tubes forming flat arrays of regularly ordered air cavities. Their piezoelectric properties and physical origin will be presented and possible novel applications, such as energy harvesters will be discussed.

## Heinz von Seggern

Heinz von Seggern studied physics at the University of Goettingen and Hannover in the field of solid state physics where he graduated in 1976. He received his PhD degree from the Technical University of Darmstadt in 1979, then became Postdoc and later principal investigator at AT&T Bell Laboratories, Murray Hill, New Jersey, USA. In 1982 his work was honoured by the Physics Prize of the Academy of Science of Goettingen. In 1985 he accepted a position as principal investigator at Siemens Research Center in Erlangen where he was promoted in 1990 to department head. In 1997 he was appointed to full professor at the Technical University of Darmstadt. His scientific interests are directed toward electrical properties of dielectrics, organic electronics (OFET, OLED) and towards medical imaging. He has published over 280 scientific papers in peer-reviewed journals.

#### Joan Ramón Morante Lleonart

Institut de Recerca en Energia de Catalunya (IREC), Spain

###### Catalyst materials for solar refineries, synthetic fuels and procedures for a circular economy of the CO2

### Joan Ramón Morante Lleonart

Nowadays, the circular economy of carbon dioxide constitutes one of the major world challenges. The conversion of CO2 into value-added chemicals and/or fuels, using renewable energy and earth-abundant elements as well as environmental friendly materials is a key priority. Under this scenario, one can distinguish three different complementary and competitive situations: i) Carbon dioxide closed loop in which this molecule is captured, reduced and oxidized continuously defining an ideal circular economy of the CO2; ii) Carbon dioxide reduction by thermochemical or plasma procedures and iii) Carbon dioxide reduction by electrochemical (dark and photo) procedures. In all of them, carbon dioxide can give rise to different reduction reactions pathways with several sub products. Consequently, catalyst materials are essentials for increasing selectivity and productivity towards determined sub product such as CO, syngas, formic gas, methanol or even methane. So, aside of the system design constraints, parameters as the over-potential values, charge transfer resistances, are determining the final energy balance as well as the overall efficiency and productivity. In this contribution, the influence of the catalyst characteristics on the final performances, faradaic efficiency and final productivity will be presented and discussed considering over-potentials, Taffel plots and the overall characteristics of the selected catalyst according to the target CO2R product. Special attention will also be paid on photo electrochemical conditions for reducing the overall cell voltage by increasing solar energy utilization up to achieving free bias conditions required for pure artificial photosynthesis under an illumination of one or few suns of the complete device. With this concept we demonstrate industrial feasibility and competitiveness of the solar-to-fuel (STF) conversion efficiency values as alternative for the future energy models considering solar refineries as paradigm of the artificial photosynthesis based on distributed photoelectrochemical procedures, PEC.

## Joan Ramón Morante Lleonart

Since 1985, full professor of the Faculty of Physics of the University of Barcelona. Since 2009 he has been the director of the advanced materials for energy area of the Energy Research Institute of Catalonia, IREC, and since the end of 2015 he has been appointed as director of this institute. Previously, he was Vice Dean and Dean of the Faculty of Physics of the University of Barcelona, director of the Department of Electronics of this university, head of studies in Electronic Engineering and co-coordinator of the interuniversity master between the University of Barcelona and the Polytechnic University of Catalonia of the master on Engineering in Energy. His activities have been centered in electronic materials and devices; the assessment of their related technologies and production processes, especially emphasizing materials technology transfer. He was involved on sensors, actuators and microsystems, especially on chemical sensors. Currently, he is focused in the mechanisms of energy transfer in solid interfaces involving electrons, photons and phonons as well as chemicals. Likewise, he is specialized in the development of renewable energy devices and systems for applications in the field of energy and environment based on nano-structures and their functionalization. His special attention is focused on advanced materials and structures for artificial photosynthesis including the production of hydrogen and fuels at solar refineries. He has co-authored more than 625 publications with more than 18000 citations (h> 68) and 23 patents, has directed 45 doctoral theses, has participated / coordinated numerous projects in different international and industrial programs (> 50), organized various international technological scientific conferences in the field of sensors / microsystems and "nano-energy" and has been distinguished with the medal Narcís Monturiol of the Generalitat de Catalunya. He has also served as vice president of the European Materials Society and is the editor-in-chief of the Journal of Physics D: Applied Physics.

#### Junbai Li

Institute of Chemistry - Chinese Academy of Sciences, China

###### Molecular Assembly of Peptide based Materials towards Biomedical Application

### Junbai Li

Self-assembly nanomaterials can form well-defined hierarchical structures which provide great opportunities in drug delivery, gene transfection, tissue engineering and biosensing fields. In the past decades, great efforts have been focused on self-assembly of peptide molecules owing to their structural simplicity, biocompatibility, chemical versatility, facile synthesis, and widespread applications. One well-known and the simplest peptide building block is diphenylalanine (FF), the core recognition motif of the Alzheimer’s β-amyloid polypeptide. In this lecture, our recent progress on the self-assembly of FF and their applications in biomedicine will be introduced. The polymorphism of FF-based assembly were obtained and easily controlled by the experimental conditions such as solvents, peptide concentrations and crosslinking agents. We hope our approach could help to enrich the diversity of FF-based peptides’ assemblies and shed light on the preparation of bio-functional materials.

## Junbai Li

PhD from the Department of Chemistry, Jilin University in 1992. He then served as a postdoctoral fellow at the Interface Department of the Max Planck Institute of Colloids and Interfaces in Germany from 1994-1996. He is currently a professor at the Institute of Chemistry, the Chinese Academy of Sciences. He has published 280 papers in international journals, written and edited five books and contributed to eight book chapters. He is the owner of 18 patents. He serves as Editor-in-Chief of Colloids & Surfaces A, Section Editor of Current Opinion in Colloid & Interface Science. His main research interests are in molecular assemblies of biomimetic systems, self-assembly, biointerfaces, design and synthesis of bioinspired materials with various nanostructures.

#### Pietro Matricardi

Department of Drug Chemistry and Technologies - Sapienza University of Rome, Italy

###### Polysaccharide hydrogels: a versatile tool for biomedical and pharmaceutical applications

### Pietro Matricardi

In the biomedical and pharmaceutical field, polysaccharide hydrogels are gaining an increasing interest due to a favorable combination of two items: the generally accepted biocompatibility of this class of polymers and the high amount of water content. This combination, resembling the extracellular matrix, is very well accepted by different kinds of human cells, and, as a consequence, polysaccharide hydrogels can be used in internal administrations without interfering with the metabolism and the normal human physiology, thus representing a valuable tool for applications in tissue engineering and drug delivery. The hydrogels can be shaped and used in the form of bulk materials or in the particulate form - from micro to nano dimensions -, thus fulfilling different needs. In particular, nanohydrogels (NHs) are very promising as they can combine the favorable properties of nanotechnologies and the features of the hydrogels. In this contest, the preparation of a new nanoparticulate hydrogel carriers based on the polysaccharides gellan (Ge) and hyaluronic acid (HA), obtained by self-assembly of polysaccharide chains, previously derivatized with hydrophobic moieties, represent an important step onward for some pharmaceutical applications.

## Pietro Matricardi

Professor at the Sapienza University of Roma, Italy. His research activity is focused on the development of new materials based on polysaccharides for drug delivery and tissue engineering applications. In this respect, he carries out researches on macro and micro hydrogel systems, on tablets, microspheres and self-assembling polysaccharide nanohydrogels. Among the various hydrogels systems, particular attention is devoted to Interpenetrating Polymer Networks based on polysaccharides or polysaccharide/synthetic polymer systems. Within the Matricardi Lab, in 2016 was founded the special unit “PolyRome” with the aim to assist private and public companies in developing new products. Pietro Matricardi currently teaches "Pharmaceutical Technology" and formerly taught “Macromolecules” and “Laboratory Safety” at the Faculty of Pharmacy and Medicine, Sapienza University of Rome. Dr. Matricardi earned his M.Sc. (Laurea) in Chemistry (1989) and his Ph.D. (1993) from the Sapienza University of Rome. In 1993, he joined the Marion-Merrel-Dow Group in the Anagni site - Italy - within the analytical development and the process development units. In 2004, he joined the Drug Chemistry and Technologies Department, of the Sapienza University of Rome, serving as Researcher and Teacher. Dr. Matricardi, currently president of the Controlled Release Society Italy Chapter, has published over 80 papers in international peer-reviewed journals, participating as lecturer at many conferences and writing a book and some book chapters.

#### You-Lo Hsieh

University of California, Davis

###### Novel structural and functional materials from biomass via sustainable strategies

### You-Lo Hsieh

Biological materials are synthesized by living organisms in a variety of sophisticated structures for unique functions that serve as inspirations for advanced materials. Processing biomass has many challenges due the complex and varied compositions as well as the non-thermoplastic nature and insolubility of biomolecular components. Material development and generation from biomass is envisioned to take advantages of these unique structural attributes while weighing in ways to overcome processing challenges. This presentation will discuss various synthesis and derivation approaches from generating biological nanomaterials to holistic utilization of single feedstock. Robust chemical reactions of biomolecules and biopolymers have been designed to enable them to be soluble, miscible with other polymers and additives, polymerizable and processable into new structures and advanced materials. Streamlined reactive isolation of crystalline domains of cellulose has offered an array of designed nanocelluloses with specific surface chemistries and nanoscale lateral dimensions and aspect ratios to serve as building blocks for chemicals and materials. Sustainable approaches to biomass conversion and utilization require significant scientific endeavor to offer biological material innovations and to meet future needs in advanced materials while reduce demand on non-renewable resources and negative environmental impact.

## You-Lo Hsieh

You-Lo Hsieh is a Distinguished Professor at the University of California, Davis and Berkeley. Professor Hsieh’s research integrates polymer chemistry with materials engineering to develop strategies for generating bio-nanomaterials and to create 1D to 3D advanced functional materials, including hierarchical and hybrid nanofibers, micro-/meso-porous fibers, thin films, and network structures such as hydrogels, aerogels and membranes. Professor Hsieh champions sustainable materials research and interdisciplinary initiatives and has mentored graduate students and researchers in disciplines and programs such as biotechnology, chemistry, chemical engineering, materials science, forensic science, and textiles as well as undergraduates across colleges. Professionally, Professor Hsieh is active in the American Chemical Society, the Fiber Society and nanomaterials scientific communities as well as mentors and collaborates with scientists from around the globe.