Seznam abstraktů 2019: SEKCE E - POKROČILÉ METODY PŘÍPRAVY A CHARAKTERIZACE NANOSYSTÉMŮ

Because of the potential use of transition metal molybdates, and namely NiMoO4, as heterogeneous catalysts for the oxidative dehydrogenation (ODH) of propane to propene, novel synthetic approaches of these materials deserve a continuous interest. Bulk beta-NiMoO4 is actually known for its superior propene selectivity with respect to the alpha-phase, but the synthesis of this metastable phase requires high calcination temperatures (> 650°C) that reduce the specific surface area and therefore the propene productivity. The challenge is therefore to master the alpha/beta-polymorphism and ensure adequate textural properties in terms of surface area and mesoporosity. A novel approach based on hybrid organic-inorganic precursors in which inorganic ions ([Ni(H2O)6)2+], MoO42-) are homogeneously dispersed in a homemade polyampholytic copolymer matrix (poly(N,Ndiallyl-N-alkylamine-alt-maleic acid) was previously implemented to prepare beta-NiMoO4 catalysts that displayed very promising performances in propane ODH [1]. Polymer matrices bearing side aliphatic alkyl chains of different lengths (C6, C12, C18) were tested. In this context, complimentary experiments were carried out to understand how the hydrophobic interactions between these alkyl chains govern the supramolecular organization of the pristine NiMo-based hybrid materials. Dodecyl side chains appear the best compromise that preserves the lamellar organization without sacrificing the capacity of the copolymer to interact with the precursor inorganic ions.

It comes out that the exothermic degradation profile of the copolymer is the key point to obtain porous beta-NiMoO4 materials, in the sense that the polar backbone and the aliphatic side chains of the copolymer burn at different temperatures. The former acts as a combustion activator and ignites at moderate temperatures (230-250°C), initiating thereby the early and rapid crystallization of beta-NiMoO4 before complete removal of the polymer matrix. The subsequent decomposition of the aliphatic part at higher temperatures then creates free space corresponding to the creation of slit-shaped mesopores in the oxide framework. These particular conditions prevent the NiMoO4 texture from sintering and allow to maintain high levels of mesoporosity, specific area and consequently catalytic activity.

[1] B. Farin, E. Gaigneaux, M. Devillers, Abstracts of Nanocon 2018 (Brno, Czech Rep.)

The problem of sintering ceramics based on yttria-stabilized zirconia (Y-TZP) has been investigated. It was studied the effect of mechanical activation using two types nanopowders obtained by two different methods (co-precipitation and technical hydrolysis) on sintering kinetics of yttria-stabilized zirconia nanopowders. The constant rate of heating method (CRH) at different heating rates was used to determine dominant at the initial sintering stage mass transfer mechanisms. The basic mechanism, activation energy (Q) of sintering for all investigated naopowders were estimated using the sintering-rate equations that are applicable to the CRH data. It has been found that nanopowder 3Y-TZP produced by the co-precipitation method was sintered according to domination of the volume diffusion (VD) mechanism (n = 1/2) and nanopowders PMM-3Y-TZP produced by using mechanical activation with different milling time were sintered by the grain-boundary diffusion (GBD) mechanism (n = 1/3).

Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is an optical microscopy and spectroscopy approach based on scanning probe technology, bypassing the ubiquitous diffraction limit of light to achieve a spatial resolution below 20nanometers. s-SNOM employs the strong confinement of light at the apex of a sharp metallic AFM tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties absorption, reflectivity) of the sample directly below the tip and yields nanoscale resolved images and nanoscale spectroscopy (hyperspectral nano-FTIR) information simultaneous to topography. This presentation we will introduce the basic principle of near-field microscopy and hyperspectral nano-FTIR for imaging and spectroscopy with 10 nanometer spatial resolution. In addition we will summarize the latest achievements in the field of near-field microscopy and spectroscopy on polymers, biomaterials and 2D materials, incl. Combination of nanoFTIR with TERS and will focus on applications in chemical analysis and material identification at the nanoscale.

Two unique instruments are presented.
The new Phenom Pharos (Thermo ScientificTM) is the first desktop SEM with an FEG source that makes crisp, high-brightness images. It can be equiped with all BSD, SED and EDS built-in detectors. Phenom Pharos is easy to operate with foolproof handling and provides the shortest time to image, thanks to its intuitive and compact advanced design.
The new Zetasizer Ultra (Malvern Panalytical) is the most advanced DLS system for the measurement of size, charge and concentration of (nano)particles. It provides ease of use, analysis speed and the most developed data quality system. Zetasizer Ultra offers two unique measurement capabilities: Multi-Angle Dynamic Light Scattering (MADLS®) and Particle Concentration, to offer even greater data confidence and insight into your samples.

Recently discovered alternative route for zeolite synthesis - ADOR (Assembly-Disassembly-Organization-Reassembly) - led to the discovery of zeolites that have not been prepared by traditional solvothermal synthesis so far. Moreover, some of them are unfeasible solvothermal synthesis targets according to local interatomic distances (LIDs) criteria. Parent germanosilicates (UTL, IWW, SAZ-1, UOV, and IWR) were hydrolyzed to form layered zeolite precursors (LZPs). LZPs have been intercalated using various organic hydroxide solutions with controlled pH. Calcination of intercalated precursors formed new zeolites (layers connected by oxygen bridges). Additional alkoxysilylation of LZPs followed by calcination results in the formation of novel zeolites with single-four rings (s4rs) units connecting layers. Some structures were obtained by transformation of parent germanosilicate in acid solutions as well as solvent-free conditions using vapours. Obtained materials were investigated using XRD, SEM, HR-TEM and adsorption of argon and nitrogen. Among the presented structures there are two new zeolites, IPC-17 and IPC-18, prepared from IWR and IWW germanosilicates, respectively. IWR zeolite was treated with 12M hydrochloric acid followed by calcination, which led to obtain the novel zeolite structure - IPC-17.
IPC-18 was prepared by ADOR approach in “solvent-free” mode. The idea is based on possible hydrolysis of Ge-O bonds by limited amount of water molecules adsorbed in the zeolite pores. The process was catalysed by vapours of 12 M HCl without contact of solid with respective solution. This led to the transformation of IWW parent into new structure indicated IPC-18. Both new zeolite structures were refined using Le Bail and Rietveld methods as well as confirmed by electron microscopy imaging methods.

For investigation of the influence of temperature of nanopowder calcination on adsorption properties of zirconiananoparticles, the pH-metry method was used. As a result, structure and parameters of double electric layer surrounding zirconia nanoparticles under wetting were calculated. According presented data, titration curves of suspensions based on zirconia nanoparticles at different electrolyte concentrations intersect at values other than σ0 = 0, which indicates the occurrence of specific sorption on the surface of zirconia nanoparticles.

The field of surface science traditionally reveals mechanistic details of various phenomena at surfaces, ranging from chemical reactions to electronic properties. While scanning tunneling microscopy (STM) was historically the main tool for obtaining the atomic-scale information, this technique became recently superseded by atomic force microscopy (AFM) in terms of spatial resolution [1], chemical sensitivity [2], and options to control and measure the charge state of single atoms or molecules [3].
I will discuss various options that the combined STM/AFM opens in the materials research of catalytically relevant compounds, namely transition metal oxides. The superior spatial resolution will be demonstrated on the clean and water-exposed binary oxides like In2O3 or TiO2. The possibility to study complex systems with ternary composition will be discussed on materials like the KTaO3 and SrTiO3 perovskites [4,5]. The nc-AFM technique is nonintrusive due to the absence of tunneling current. This offers intriguing opportunities for investigating complex hydrogen-bonded networks or tracing single electrons in molecules [6] and bulk crystals.
REFERENCES: [1] L. Gross et al., Science 2009, 325, 1110., [2] L. Gross et al., Science 2009, 324, 1428., [3] Y. Sugimoto et al., Nature 2007, 446, 64., [4] I. Sokolovic et al., Phys. Rev. Materials 3, 034407 (2019)., [5] M. Setvin et al., Science 359, 572-575 (2018)., [6] M. Setvin et al., PNAS 114, E2556 (2017).

Quantitative Magnetic Force Microscopy (QMFM) is becoming increasingly popular as an emerging technique used for the measurements of the stray field distribution of the magnetic samples at the nanometer length-scales. Worldwide, many groups are working on protocols which enable reliable evaluation of the measured data. Unlike in two-pass phase MFM measurements which are nowdays routinely implemented in commercial AFM tools, the QMFM brings many chalenges to be overcome. Different approaches including patterned magnetic calibration samples, special tips with well-known magnetization etc. were introduced. All these techniques suffer from one common dissadvantage which is the necessity of a special and almost always very specific calibration sample or probe which is usually hardly reproducible. Any tracebility of such a measurement becomes then almost impossible.
In our approach we rely on current loops as calibration samples made by a standard lithographic techniques. This approach anables direct measurements of the ring dimensions using the same AFM with well know uncertainties as well as using variable currents supplied by the calibrated sources. In this approach all the uncertainties can be directly evaluated with a high accuracy. Such current loops can be easily prepared by any lithography lab. The measured data can be then easily evaluated using analytical tools implemented in the SPM software such as Gwyddion which is freely available for the public use.
Such a versatile and portable calibration standards will be further calibrated in cooperation with the Czech Metrology Institute (CMI) which enables to use them as legal calibration standards with well-known uncertainties.

We introduce a straightforward mathematical method for improving the AFM image resolution, applied to image analysis of helicene-based macrocycles adsorbed on HOPG. The method reveals structural details from insufficiently resolved AFM images and attributes them to internal structure and ordering of the macrocycles. Our findings are also corroborated by molecular mechanics simulations, validating that the structure provided by the method has lower potential energy compared to other tested macrocycle arrangements.

The introduction of the latest news in the TESCAN portfolio. TESCAN ORSAY HOLDING is a leading global developer and supplier of Scanning Electron Microscopes (SEMs) and Focused Ion Beam Scanning Electron Microscopes (FIB-SEMs) systems, and the French company ORSAY PHYSICS, a world leader in customized Focused Ion Beams and Electron Beam Technology.
TESCAN strives to continuously keep improving their products, which creates a competitive advantage for its customers. The TESCAN brand is becoming established thanks to the company's participation in top research projects and cooperation with the leading companies in the field of electron microscopy and microanalysis.

Company Moorfield provides a range of laboratory systems for PVD, CVD, etching and annealing. In this short presentation you will see the flexibility in deposited materials (graphene, carbon nanotubes, metals, insulators, organic materials) which is reached by wide range of offered deposition techniques like thermal evaporation, e-beam, magnetron sputtering or chemical vapor deposition. Powerful as larger deposition system but for affordable price.

The interest of scientists in nanomaterials and their development started a revolution in industry roughly 30 years ago and nowadays the nanomaterials are present practically in each household. Despite our efforts to understand the physics and chemistry behind nanomaterial properties, conflicting results describing the same nanomaterial are published each day. Typical examples are nanomaterials tested in biological studies. Even if the nanoparticles have been prepared by the same protocol and characterized by the same physical and chemical methods, but in different laborites, they may show different toxicity.
That leads us to a conclusion that the bulk methods used to characterize ensembles of nanomaterials ignore some important properties of individual nanoparticles. Therefore, we decided to develop a multi-characterization device, which enables us to measure and study physical and chemical properties of individual nanoparticles. The setup consists for now from atomic force microscope (equipped with conductive-AFM, Young modulus, Akiyama probe and scanning tunneling modules) with ability to work in liquids combined with luminescence micro-spectroscopy setup.
This device enables us to study physical properties of individual nanoparticles combined with spectral characterization and the electrical measurements give us information about chemical reactivity of an individual nanoparticle. The distributions of properties of individual nanoparticles are then compared to properties measured by standard methods on ensembles of nanoparticles. We believe that this device and our studies will contribute to new field of studies nano-reconnaissance.

As Materials Researchers, we are interested to determine the structure (phases, grains, cracks, porosity), properties (mechanical, chemical, thermal, electrical), performance (corrosion, oxidation, energy efficiency, reliability, etc.) and the processes (for example sintering, annealing, grinding, additive manufacturing, etc.). In the center of the materials science tetrahedron lays characterization, the tool that researchers use to determine the relationship between structure, properties, performance and process of materials. Here, by characterization we understand microscopy, spectroscopy, modelling and simulations as well as image analysis. Since the development of the first microscope cameras, researchers and operators have sought to extract quantitative, actionable information from micrographs to further advance their research and improve their processes. There are several issues with conventional image processing by thresholding. It generally requires expertise and it is hard to check that the answer is correct - while image analysis will always give you a result, you need an expert to be sure you have the correct result. However, there are various problems with conventional image processing and segmentation. This is why ZEISS launched ZEISS ZEN Intellesis which can overcome the problems of traditional image segmentation and analysis - it is a module for segmentation of images in a better way than conventional image analysis. It can be repeatedly retrained until it gets it right and can understand things like local texture, ignoring tiny holes, areas of similar contrast but different pattern etc. Once trained, it can be used on large data sets, or just applied automatically to a large number of individual images.

Atomic force microscope (AFM) LiteScope™ produced by NenoVision is carefully designed for direct integration into many different types of scanning electron microscopes (SEM). It is equipped with unique technology for true correlative imaging - Correlative Probe and Electron Microscopy™ (CPEM). It allows simultaneous measurement of various signals of SEM, AFM and other related techniques like Electron Beam Induced Current (EBIC) or Catodoluminiscence (CL). LiteScope also enables using other methods such as Focused Ion Beam (FIB), Gas Injection System (GIS) or Electron Dispersive X-ray (EDX) to modify and right away analyze the sample surface. Among the main applications belong e.g. 3D surface characterization, height/depth profiling, surface roughness calculation, precise tip navigation, nanoindentation and nanomanipulation, variety of spectroscopic regimes, measurement of electrical and mechanical sample properties, etc.

In the work, preceramic organomagnesiumoxanealumoxanes hydrolytically stable in air and soluble in organic solvents, exhibiting fibre-forming properties at Al:Mg molar ratios of 2:1 have been synthesized. The MgAl2O4-spinel nanopowders were obtained by pyrolysis of a ceramic-forming oligomer in the air at 700°, 800° and 900°C and were characterized by X-ray, SEM and particle size analysis. The powder kinetic compressibility curves were obtained by the uniaxial two-side pressing method at a constant movement speed a plunger. The magnesian spinel nanopowders rheological properties were studied: a compressibility factor, a compressibility modulus and a deformation limit value were determined. The effect of pyrolysis temperature on the compressibility of the powder was shown. It was found that an increase in the pyrolysis temperature leads to a decrease in the relative density of the green body (from 54% to 45%, respectively, at 700°C and 900°C) and an increase in the compressibility factor. Apparently, this is due to the transition of the material from amorphous to crystalline, which is confirmed by X-ray powder diffraction.
ACKNOWLEDGEMENTS: The work was supported by the Grant of the President of the Russian Federation No. MK-39.2019.3

The production of nanoparticles in larger scale requires a continuous production process. This contradicts with outputs of basic research that uses predominantly batch synthesis. A continuous production of nanoparticles may fail when the size, shape and distribution of nanoparticles depend on nucleation way and/or intensity of mixing and diffusion. This can be improved by turbulent flow, ultrasound apply, or other techniques. However, such continuous synthesis improvements may not be sufficient. The use of microemulsion techniques is therefore promising.
The synthesis of iron oxide nanoparticles was chosen as a model case for the assessment of the microemulsion synthesis in continuous flow. A water-sodium dodecyl sulphate (SDS)-cyclohexene system has been chosen as the microemulsion system for dissolving mixtures of iron II and III, ammonia, and stabilizing ligands. Microemulsion solutions of starting materials were prepared and subsequently mixed in a ultrasound flow reactor under various conditions (concentration, flow rate, temperature).
The product was purified and transferred to the aqueous phase. The result was colloid solution of iron oxide nanoparticles in water of 5-200 nm in size with a zeta potential ranging -25 to -57mV. The final product was characterized by UV VIS, powder XRD, dynamic light scattering, electron microscopy, electron diffraction.
The results showed that use of water-in-oil microemulsions is a perspective method of nanoparticle synthesis to obtain product in larger quantities.

The non-thermal plasma (NTP) techniques proved to be efficient tool in many diverse scientific and industrial areas. Its applications ranging from synthesis of nanostructures and decontamination to surface modification. One specific application of NTP is the generation of the so-called plasma activated water (PAW). The NTP treatment of water is followed by several processes which form the resulting properties and chemical composition of PAW: (i) water absorbs a stream of reactive species, which accompany the generation of plasma in the used atmosphere, (ii) the impact of high energy electrons on the water generation water-related species, (iii) a mutual reaction of species from (i) and (ii). We have proved that under appropriate conditions the PAW treatment can effectively oxidize surface of nanostructured polypyrrole, deprotonate it without any chemical artefacts and perform controlled and fast ageing and stabilization of fresh polymer that usually takes sever weeks. We have also showed that the exposure of the semiconductor nanoparticles (Si, ZnO and MgO) to the cocktail of the reactive species in PAW results in the modification of their original surface termination, primarily by the products of reactive oxygen species and nitrogen radicals. These modified nanoparticles exhibit greater chemical stability, solubility in water, deagglomeration and in the case of luminescent nanoparticles also improved optical performance. According to our results, the PAW treatment of various nanostructures demonstrated to be inexpensive, fast and easy way in modification of their surface chemistry and thus wide range of physical properties. These nanoparticles will be further studied by single dot techniques.