Seznam abstraktů 2021: POSTEROVÁ SEKCE E

Microwave Plasma Enhanced Chemical Vapor Deposition (MWPECVD) is widely used for the growth and the study of synthetic doped diamond and its electronic and electrochemical applications. Recent results show the possible enhancement of dopant incorporation in diamond using pulsed gas injection in the reactor. Therefore, understanding the gas dynamic of the MWPECVD reactors is crucial to the optimization of the gas flows and diamond doping.
In this work, we present a method to determine the gas dynamic response a MWPECVD reactor. We determined the dynamic response of injected gas in a lab-made NIRIM1 type MWPECVD reactor by recording light emission from an hydrogen plasma during the instantaneous injection of a small fraction of nitrogen using either Optical Emission Spectroscopy (OES) or the combination of a photodiode and different optical band filters. The measurements were carried out for different hydrogen flows. The optical emission data were fitted using the impulse response equation proposed by H. Pendar et al.2. Using linear system theory, we developed a program to determine the dynamic response of the reactor to an arbitrary shaped gas flow input from its pulse response3,4.
ACKNOWLEDGEMENTS: The financial support from the following sources is gratefully acknowledged: The Czech Science Foundation grant ID: GACR 21-03538S, the SGS Student Grant ID: SGS21/057/OHK3/1T/13, and the Operational Program Research, Development, and Education financed by European Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports (Project No. SOLID21 - CZ.02.1.01/0.0/0.0/16_019/0000760).
REFERENCES: [1] M. Kamo, Y. Sato, S. Matsumoto, and N. Setaka, Journal of Crystal Growth 62, 642 (1983).; [2] H. Pendar and J.J. Socha, PLoS ONE 10, e0139508 (2015).; [3] B. Porat, A Course in Digital Signal Processing (John Wiley, New York, 1997).; [4] J.D. Hamilton, Time Series Analysis (Princeton University Press, Princeton, N.J, 1994).

Conductive polymers are an ideal material for application in health monitoring biosensors in wearable electronics because of their electrical conductivity, large surface area, and environmental stability, and for that purpose it is necessary for them to be stretchable and self-healable. This can be achieved by introducing side chains containing hydrogen bonding species which enable non-covalent cross-linking between conducting polymers, while maintaining the high conductivity of the backbone.
In this work, a novel multiphase design for highly stretchable, room temperature healable and conductive polymers is used. The backbone consists of poly(3,4-ethylenedioxythiophene) (PEDOT) onto which polycaprolactone (PCL) side chains are grafted. Anionic ring-opening polymerization is used as a tool for tailoring the desired graft polymers, which allows the assembly of polymers with specific tailored functionalities, in this case with optimal density and side-chain length. Different polymerization conditions were used to obtain different PCL chain lengths and effect on properties was evaluated by multiple techniques. The structural properties of the synthesized materials were characterized using techniques such as nuclear magnetic resonance (NMR), infrared spectroscopy (FTIR) and UV/Vis spectroscopy as well as gel permeation chromatography (GPC). The electrochemical properties were studied by cyclic voltammetry and four-point probe method, while the thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).
The analyses confirmed the successful synthesis of conductive graft polymers with increased stretchability while maintaining good conductive properties.
ACKNOWLEDGEMENTS: This work has been supported by Croatian Science Foundation under the project UIP-2019-04-8304.

Light scattering techniques represent a group of methods providing the absolute information on the molecular weight, particle size, conformation, polydispersity and also the stability of analyzed dispersion systems. These techniques are primarily used for the characterization of biopolymers, synthetic polymers and nanoparticles. The utilization in the area of alkaline-activated materials based on blast furnace slag is more challenging, mainly due to their highly alkaline nature and also their generally used high content of solid fractions dispersed in liquid media. This contribution was focused either on the optimization of sample preparation, as well as on the definition of the optimal setting of measuring parameters to be able to properly use the electrophoretic light scattering (Zetasizer Nano ZS; Malvern Panalytical Ltd.) for the description of the stability of these complex samples. For these purposes, we studied dispersion systems of blast furnace-slag in alkaline-activation solution (both sodium hydroxide activation and also sodium silicate solutions with different molar ratios of SiO2/Na2O) containing lignosulfonate as a plasticizing admixture. The obtained zeta potential provided crucial insight into the individual sample stability and also the possible interactions with the used plasticizer. The results are indicating that the proper technique of sample dispersion and the maintenance of the precise content and ratios of individual components represent important parameters managing the stability of alkaline-activated materials based on slag.

Zinc oxide (ZnO) crystalline powder is a low cost and environmentally friendly material with unique optical properties and variety of nano and microstructures such as microrods, nanorods or hedgehog-like particles. The hydrothermally grown ZnO nanorods (ZnO NRs) with their high surface-to-volume ratio and related size effects impose challenges for energy conversion, scintillators, photocatalytic wastewater treatment, electrochemical energy storage or sensing applications [1]. We have shown that plasma hydrogenation effectively suppresses ZnO defects, leading to a significant increase in electrical conductivity and exciton-related UV luminescence.
To further study such effects, we employed a custom-built inductively coupled plasma (ICP) 13.56 MHz reactor with up to 300 W RF discharge power. ZnO NRs were exposed to the ICP plasma with a mixture of hydrogen and argon for up to 30 min, followed in-situ by plasma oxidation. Plasma properties were monitored by optical emission spectroscopy (OES) and by measuring the self-bias potential of the stainless steel sample holder separated from the ground by a blocking capacitor. The exciton-related UV photoluminescence of ZnO nanorods and optical absorption increases significantly after the plasma treatment. We attribute it to the complex changes of ZnO surface electronic states that also give rise to its black color visually. The changes in surface chemical composition were investigated by XPS. ACKNOWLEDGEMENTS: The work has been supported by the Czech Science Foundation project 19-02858J, by CAS-SAS Mobility Plus project SAV-AVCR-21-09, by the OPVVV project SOLID21 - CZ.02.1.01/0.0/0.0/16_019/0000760, by the Slovak Scientific Grant Agency project VEGA 2/0157/20, by the Ministry of Science and Technology of Taiwan (MOST) under the grant No. 108-2923-M-153-002-MY3 and by the project Strategy AV21 (program Diagnostic Methods and Techniques). REFERENCE: [1] J. Mičová, M. Buryi, D. Šimek, J. Drahokoupil, N. Neykova, Y.Y. Chang, Z. Remeš, O. Pop-Georgievski, J. Svoboda and C. Im, Synthesis of zinc oxide nanostructures and comparison of their crystal quality, Applied Surface Science 461 (2018) 190-5.

This work focuses on the determining of the hydrogel structure using fluorescent nanoparticles. As the main method was chosen fluorescence lifetime imaging microscopy (FLIM) and subsequent analyzes were performed by specialized programs. One of these program is able to create basic FLIM image. The other program processes these images into Euclidean distance map. Thanks to them it is possible to determine the mesh size and show the approximate structure of the hydrogel network. It is also possible to create 3D structure of the hydrogel from FLIM images obtained from z-scan.
The another type of measurement was using nanoparticles of different diameters and excitation and emmision wavelenghts. They make it possible to track sites of varying pore sizes within a single experiment.
Aqueous solution of agarose was chosen as the physically crosslinked type of hydrogel and aqueous solution of sodium alginate as the chemically crosslinked type of hydrogel for these experiments. Fluorescent-labelled silica and gold nanoparticles with diameters ranging from 10 to 100 nm were used as fluorescent probes.

This contribution is focused on utilization of a sequential chemical fractionation method for determination of organic matter content, its distribution in biochar and the possible use of biochar as a soil conditioner in agriculture. For these purposes the optimized chemical fractionation procedure was used to reveal the content of organic matter in different biochar samples with different properties (samples with European biochar certification for usage in agriculture) which depend significantly on the temperature used during a pyrolysis of biomass residues in the process of biochar production. In parallel, these samples were also fractionated by classic alkaline extraction to obtain the so-called extractable fraction of organic matter (NOM).
Biochar is one of the important soil conditioners, known for having positive effect on crop yield, soil quality, nutrient cycle and carbon sequestration due to the transfer of organic carbon from it to the soil. However, the effect depends on the properties of the biochar, its doses to the soil, but also on the properties of the soil itself. Surprisingly, some authors point to the fact that biochar does not always have a positive effect on soil, plants or microfauna. Therefore, it is necessary to perform its depth characterization to be able to predicts its role in soil and its optimal application dose.
Individual fractions obtained from sequential chemical fractionation as well as NOM samples were characterized by methods of elemental analysis (determination of organic elements content), thermogravimetry (contents of ash, organic matter and moisture) and FTIR spectrometry (structural analysis). The results showed that the method of sequential chemical fractionation gives higher yields of organic matter compared to classical alkaline extraction. Moreover, the obtained fractions divided according to solubility and strength of binding to soil inorganics can be better characterized by physical-chemical methods, which provides more detailed information about organic matter in biochar and its possible effect on soil properties.

Combination of two-dimensional (2D) materials and semiconductors is considered to be an effective way for fabricating electrocatalysts for solving the environmental pollution. In this work, V2C MXene was obtained by Acid Etching Method and 2D/2D heterojunction of V2C /BiVO4 was successfully synthesized by ampoule method. The crystallinity and composition of as obtained samples were investigated by XRD. The disappearance of typical XRD peaks of V2AlC after etching proves the total removal of the Al layer in V2C. In addition, the characteristic XRD peaks for both V2C and BiVO4 were detected in V2C/BiVO4 . SEM as well, showed nanoflake of BiVO4 were firmly assembled on the surface of the V2C nanosheets. This work demonstrates that V2C MXene could be a promising carrier to construct 2D/2D heterojunction for NRR.

Diffraction and refraction optically variable image elements are basic building blocks of planar structures for advanced security of documents and valuables. A sampler of 36 mesh diffraction structures - binary, tertiary, quaternary and blazed gratings (period range 400 nm - 20,000 nm) - represents a cross-section throughout technological steps - mastering, galvanic replication and embossing. Electron beam writing technology with Gaussian beam and electron energy of 100 keV was used to create the master. With very small forward scattering of high energy electrons, it is possible to create a linear grating with a period of down to 100 nm. An important advantage of high resolution electron beam lithography is its substantial flexibility in combining possible planar structures with significantly different parameters, such as very dense and relatively shallow structures together with deep structures (approx. 10 microns) with precise shapes (micro lenses or Fresnel structures). For protection of documents and valuables, interesting results are induced with planar optical structures consisting of non-periodic arrangements, which are characterized by high robustness to counterfeiting and imitation.
While the origination process is available for grating period down to 100 nm, the mass replication technology appears to be a bottleneck of the entire technological process. Measurement of topology and profiles of the structures by atomic forces microscope and documenting the quality of technological process of the three steps of replication of planar optically variable elements was performed for all 36 structure types of sampler.

Implantation of nitrogen particles into titanium target changes (improves) its hardness and tribological properties in the depth ranging from a few up to hundreds of nanometers. In order to understand how these properties are influenced, it is important to determine the N concentration across the depth, i.e., atomic distribution, of the modified target. However, different experimental methods determining atomic distributions are subjected to various instrumental errors and samples imperfections. To obtain expected atomic distributions without such errors, computer simulations are being advantageously used. In this work, using atomistic molecular dynamics (MD) method and our self-implemented time saving algorithm for ion implantation, we predict N depth distributions and their characteristics (N concentration maxima, corresponding depths, and full width at half maxima) in α-Ti as a function of N fluences (within 0.25 - 5.00 ∙ 1017 ions/cm2 range and with 90 kV accelerating voltage). Single N particles and N2 molecules are implanted with the ratio of N to N2 = 30 % : 70 %. The MD data are compared with fast standard Monte Carlo simulations coded in Transport of Ions in Matter (TRIM) and with experimental profiles obtained by Secondary Ion Mass Spectrometry (SIMS) and Glow Discharge-Optical Emission Spectrometry (GD-OES). We confirm that the MD distributions improve TRIM predictions, have in general good correspondence with the experiments, and suggest expected distributions for an ideal implantation situation, i.e., stripped out of instrumental measuring errors and samples defects.

We examine the validity of assumptions commonly used for the analysis of bonds (bond fractions) in amorphous W-B-C systems by a deconvolution procedure applied on measured XPS profiles. We focus on the relationship between the chemical shift of 4f electronic states of W atoms and the relative amounts of W-X bonds. The bond fraction analysis of amorphous W-B-C assumes that the formation of binary W-B and W-C bonds leads to a shift of 4f electron binding energies to lower and higher values, respectively, due to the differences in the Pauling electronegativity of W, B and C. Different W-B-C compositions also lead to different relative amounts of W-W bonds but their effect on the chemical shift is usually neglected. To test these assumptions we generated amorphous W-B-C atomic model of W40B30C30 composition (atomic percent), calculated the W 4f core electron binding energies from ab initio methods and examined relationships between the W-X bonds and the chemical shift of 4f electron binding energies. Our analysis confirms the expected chemical shifts in W-B-C caused by W-B and W-C bonds. Additionally, we found a correlation between W-W bonds and W 4f electronic states and discuss its influence on the bond fraction analysis.

Mxene are unique two-dimensional (2D) materials with a general formula Mn-1XnTx (n = 1 ... 3), where M means transition metal, X is a C or N atom, and TX belongs to functional groups, such as -F, = O and -OH. Customizable chemical composition and structural diversity give MXenes distinctive properties that lead to their use in many promising applications. However, it is known that individual MXene flakes are not resistant to oxidation in the presence of oxygen and can be spontaneously degraded with formation of TiO2 nanocrystals. Conmmonly, the oxidation process begins with the edges of flakes or with any defects on basal planes and can be suppressed by the reduction of the oxygen content in the environment. In practice it can be realized through changing the solvent, purging of suspension with with inert gases to remove oxygen, or storage under vacuum. However, these processes are not compatible with utilization of MXene in some certain applications, like elecvtrochemical catalysis (for example - oxygen evolution or oxygen reduction reactions).
In our work, we offer a new plasmon-induced method for protecting the edges of MXene from the oxidation process in aqueous solutions, as well as for their utilization as OER catalyst. MXene modification was carried out primarly on the electrode surface in the presence of organic iodonium salt with CF3 groups (IS-CF3) and under simultaneous irradiation with near-infrared light and application of a small negative potential. Under the NIR irradiation a localized plasmon is excited only on the edges of MXene flakes. The application of a small potential and the spatial-selective excitation of the localized plasmon activated the IS-CF3 with spatially restricted nano-precision. Activated IS-CF3 is splitted on active radicals, which immediately graft the neigbouring surface - i.e. MXene edges. In turn, the presence of -CF3 fluorinated groups on the edges of MXene’s flakes has protected the edges and prevented the initial TiO2 formation. As result, the associated formation of titanium oxide on the flakes surface was significantly reduced, even after MXene utilization as OER catalyst.

Iron(III) oxides are still viewed as application-promising materials due to their favorable physical, chemical and other properties. Iron(III) oxide exists in four stable crystalline polymorphs, α-, β-, γ- and ε-Fe2O3, whereas each of these phases has its specific crystal structure and hence also physical features. Specifially, ε-Fe2O3 is a rare iron(III) oxide phase. ε-Fe2O3 is still hard to synthesize as a single-phase. Moreover, due to the thermodynamic reasons, it can be synthesized only in the nanosized form.1 ε-Fe2O3 exhibits a high coercivity at room temperature, coupled magnetoelectric features and ferromagnetic resonance in microwave domain. For these reasons, it is widely regarded as an intriguing material for magnetic storage media and spintronic devices and as a suppressant of unwanted electromagnetic interference in signal transmissions. However, this is conditioned by the preparation of ε-Fe2O3 in larger amounts with a definite level of purity. Moreover, the understanding of properties, tuned by using various preparation conditions and various dopants, is necessary.2
This contribution presents a method to synthesize pure ε-Fe2O3 nanoparticles and ε-Fe2O3 nanoparticles doped with Ga atoms, employing a sol-gel synthetic protocol.3 Various factors influencing the preparation and thus the purity of the prepared nanoparticles have been studied and assessed. The influence of increasing the temperature of heat treatment on increasing the amount of ε-Fe2O3 phase in the prepared samples was observed. For determination of the structure and composition, X-ray powder diffraction, electron microscopy techniques, 57Fe Mössbauer spectroscopy, and magnetization measurements were used. The values of coercive field, saturation magnetization, and remanent magnetization were also determined for a synthesized ε-Fe2O3-based nanoparticles and also for ε-Fe2O3-based nanoparticles doped with Ga atoms. Following the results, the optimized conditions for preparation of pure ε-Fe2O3 (over 93 wt. %) were identified. Moreover, the effect of doping on the magnetic features of ε-Fe2O3 was deduced.
REFERENCES: [1] J. Tuček, R. Zbořil, A. Namai, S. Ohkoshi, Chem. Mater. 2010, 22, 24, 6483-6505 (2010).; [2] J. Jin, S. Ohkoshi, K. Hashimoto, Adv. Mater. 2004, 16, No. 1, January 5 (2004).; [3] M.Gich, M. Popovici, D. Nižňanský, A. Roig, C. Savii, L.Casas, E. Molins, K. Zaveta, C. Enache, J. Sort, S. de Brion, G. Chouteau, J. Nogués, Chem. Mater. 16, 5542-5548 (2004).

The emergence of Mxenes as a new group of 2D materials with promising applications has sprouted much interest in their characterization and chemistry. As has been shown in recent studies the terminal (T) groups formed on the surface of Mxenes after etching can consider-ably affect the elastic, optical and chemical properties of the final product. For now the main go-to method for the determining which type of T groups are present and to a degree their ratio, has been solid-state NMR. Using density functional theory (DFT) with the PBE functional and D3BJ dispersion correction method we have obtained the exfoliation energies and equilibrium interlayer distances in bulk Mxenes for various types of T groups (-F, -OH, -O) on V2CTx and Ti2CTx in different ratios. This provides an insight into the structure of these materials before exfoliation and possible way of identification based on more accessible and cheaper methods like XRD spectroscopy.

The main aim of the present work was to study the mechanical properties of nanocomposite thin films with plasma polymer structures. Plasma polymers were deposited in a capacitively coupled radiofrequency discharge from a mixture of monomer hexamethyldisiloxane (HMDSO) and oxygen as carrier gas. The flow rate of HMDSO was 3.5 sccm, the flow of oxygen was 10 sccm and the power supply of CCP was 25 W. Deposition time varied in the range 1 - 90 minutes what resulted in thicknesses in the range 0.4 - 15 micrometers. To obtain a comprehensive and complex analysis of mechanical properties, nanocomposite plasma polymers underwent measurements by various indentation methods (partial unloading, creep tests, dynamic nanoindentation, etc.) with changing indentation parameters (duration of individual segments, loading/unloading rate, oscillation frequency, etc.). The indentation tip is capable of sample surface imaging what was utilized to study the effect of chosen place for indentation. Atomic force microscope (AFM) was used to sample surface imaging as well to achieve more reliable topography information and on top of that, phase shift imaging was performed. The research has been supported by the Czech Science Foundation under project GACR 19-15240S.

This study is focused on the preparation of thin films by plasma-enhanced chemical vapor deposition in capacitively coupled plasma with biasing of the electrode with direct current/voltage. Thin films were grown in dusty plasma conditions to create nanocomposite-like thin films. Dusty plasma conditions were achieved by mixing hexamethydisiloxane with oxygen and acetylene. These nanocomposite-like thin films have great potential in a wide range of usage, due to their properties like viscoelasticity, abrasion resistance, hydrophobicity, etc. However, the main disadvantage of these films is that during their growth the bias voltage is not constant and depends on a lot of factors like length of deposition, history of a reactor, etc. Due to this variation of factors that influence the properties of deposited films, it is difficult to reproduce some depositions. We came with a simple RLC circuit to add DC bias to RF deposition to improve the reproducibility of such films. The prepared films were analyzed by AFM, FTIR, XPS, WCA, confocal microscope, and nanoindentation techniques to obtain comprehensive information about the film properties. ACKNOWLEDGEMENTS: The present work is supported by Czech Science Foundation under project GACR 19-15240S.

It is already known, that porphyrin-bases are offering better protection against steel corrosion than metalloporphyrins due to their ability to form very stable metallic complexes by linking in their inner core the iron contained in different steels. In this respect, 5-(4-carboxy-phenyl)-10,15,20-tris-(4-phenoxy-phenyl)-porphyrin was synthesized by multicomponent Adler-Longo synthesis, using two different aldehydes and pyrrole, characterized to certify the structure and further used for formulating double thin layers in all possible combinations with MnTa2O6. The pseudo-binary oxide nanomaterials MnTa2O6 were synthesized by solid-state method. The corrosion protection exhibited by these nanostructures alone or in composites after deposition on carbon steel was comparatively assessed in acid environment. Different electrochemical techniques, such as: open circuit potential measurement and potentiodynamic polarization technique with Tafel representation were used. The performed tests reveal that corrosion protection is fairly good, with the best results indicating that the electrode covered with 5-(4-carboxy-phenyl)-10,15,20-tris-(4-phenoxy-phenyl)-porphyrin / MnTa2O6 has offered the best corrosion inhibition efficiency of 86.05%.
ACKNOWLEDGEMENTS: This paper is supported by the project PN III nr. 528PED / 2020 “Hybrid ceramics/porphyrins, deposited by pulsed laser deposition as single and sandwich layers for corrosion inhibition of steels in acid environment” and partially by Romanian Academy through Programme 3/2021 from Institute of Chemistry “Coriolan Dragulescu”.

An overwhelming majority of applications of nanofibrous webs requires sufficiently smooth character of nanofibres surface. This character is apart other parameters strongly influenced by a concentration of chosen polymeric material in the solvents. Qualitative attributes roughly depend on the prepared concentration, specifically whether it belongs to one of the four basic regions: dilute, semidilute unentangled, semidilute entangled and concentrated. A concentration separating the latter two regions is often taken as a zero-th approximation indicating an onset of beadless nanofibrous webs. The present contribution uses as a more precise indicator behaviour of so-called phase angle relating viscous and elastic moduli, in other words mutual participation of viscous and elastic components. To this aim three frequently used materials were used: 1) copolymer of poly(vinylidene fluoride) and hexafluoropropylene (PVDF-co-HFP) dissolved in N,N´- dimethylformamide (DMF), 2) poly(ethylene oxide) (PEO) dissolved in water, 3) poly(vinyl butyral) (PVB) dissolved in ethanol.
For materials exhibiting first a constant behaviour or moderate decrease in a phase angle for lower concentrations, an approximation of the starting concentration is given by a concentration value where a phase angle curve starts to decrease, apparently reflecting a more progressive viscoelastic nature. As shown, such approximation provides relatively very good approximation enabling to eliminate a traditional trial-and-error method.

Gold nanowires present excellent conductivity and chemical stability, making them valuable candidates for potential applications as interconnects in electronic, photonic and optoelectronic devices. Gold nanowires can be fabricated by a variety of methods like liquid phase synthesis, templated growth on silicone or carbon structures, or the metallization of biological proteins or DNA structures. However, deposition and growth on the outer surface of these structures produces nanowires with sub-optimal chemical purity or morphology. Therefore, we sought to develop a new approach to fabricate AuNWs within the cavity of bionanostructures, by using microtubules as a mould. Microtubules are biopolymers of alpha and beta tubulin that polymerise into hollow tubes with an inner diameter of approximately 15 nm. Microtubules could be grown in vitro to a length of several micro-meters. Fabricating gold nanowires within the microtubule lumen provides (i) nanowires with a high aspect ratio and a diameter around 20 nanometers to balance conductivity and mechanical strength, (ii) work at moderate conditions (room-temperature) (iii) inexpensive and easily adoptable techniques for non-experts.In this project, we target gold nanoparticles of 1.4 nm diameter to the lumen of GMPCPP-stabilized microtubules, by covalently linking them to lumen-targeting monoclonal anti-acetylated αK40 antibodies. Attached to the luminal site of the microtubule wall, these gold nanoparticles subsequently act as seeds for the electroless deposition of gold using a soluble gold precursor (HAuCl4) and a reducing agent (NH2OH). The stabilized microtubule walls restrict and guide the growth of the seeds into nanowires with a defined diameter and a smooth morphology. In the future, we aim to encapsulate Quantum Dots and other fluorescent probes into the microtubule lumen. Lumen-functionalized microtubules can then be utilized in association with molecular-motors for gilding-assay based applications such as molecular sorting, bio-diagnostics and nanometric surface imaging.

Shear thickening fluid (STF) - often referred as dilatant fluid - is a non-Newtonian suspension of a solid component in a liquid carier, with unique ability of dissipating the impact energy. The viscosity of STFs increases abruptly with growing shear rate. Beyond the critical value of the shear rate the fluid transforms from liquid-like to solid-like state. High-grade dilatant fluids beside the appropriate rheological properties and protecting capability have to present high structural stability. The unique properties of the STFs make them sutable for human body protection. The STFs provide lots of opportunities for creating composites with great energy absorption ability, for example in smart armours or sport protectors.
The properties of shear thickening fluid, modified by the addition of multiwalled carbon nanotubes (CNT), were characterized. The addition of small amount of carbon nanotubes, to shear thickening fluid, leads to increase of maximal viscosity, from 2128 to 12213 Pa·s. To show the differences between various compositions, the microstructures of fluids were observed by scanning electron microscopy (SEM). The pronounced influence of the CNTs on the ability of impact force absorption was noticed. The protective structure containing 55 and 0.25 vol.% of fumed silica and CNTs, respectively, is able to absorb up to 74% of impact force.

In recent years the study of mechanical properties using atomic force microscopy (AFM) has become very popular. As it uses much lower forces than nanoindentation methods it allows to focus on smaller volumes which makes it an excellent tool for the study of thin films and the creation of high resolution maps. Although it gives a quantitative as well as a qualitative analysis the he quantitative aspect some open problems remain in the quantitative aspects. One of the problems encountered is related to the stiffness of the AFM cantilever. Most microscopes offer built-in methods for the calibration of cantilever stiffness. Unfortunately, these are often insufficient from the point of view of metrology. Uncertainties and traceability are rarely discussed.
Alternatively, the stiffness of a cantilever can be determined using a nanoindentation device. This well-known method offers simpler uncertainty analysis and traceability. In this contribution we explore the possibilities of this method from the metrological point of view. We shall present an uncertainty budget with focus on repatibility and we shall also discuss traceability issues. The results will also be compared to other methods.

Application of surface-enhanced Raman scattering (SERS) is a powerful method in the analysis and detection of organic and bioorganic molecules. The are many efforts, aimed at the combination of this very sensitive approach with Raman optical activity measurements - the so-called surface-enhanced Raman optical activity (SEROA) approach. Despite many efforts, aimed at SEROA utilization for enantioselective discrimination or enantiomers mixture analysis, this method has one significant drawback - the local polarization of electric field in plasmonic hot spots is linear, and thus, the chiral contribution in the SEROA spectrum is commonly small. To solve this problem, several recent works were aimed at the creation of peculiar plasmon-active nanostructures, able to support plasmon (super)chiral near field distribution. In this work, we presented an alternative design, based on the coupling of specific chiral-plasmonic structures with shuriken-like geometry and silver hot spots. The excitation of silver hot spots takes place by shuriken super-chiral near field, which allowed us to discriminate the various enantiomers of small or large organic and bioorganic molecules. It is supposed that the combination of proposed disposable plasmon-coupled structures can make the SERS enantiomer discrimination a commonly available technique with the utilization of standard Raman spectrometers instead of more rarely ROA equipment.

The Raman (Ra) and photoluminescence (PL) microscopies are eminent tools for exploring electronic, optical, and spin phenomena in two-dimensional (2D) materials. We have used the cryomagnetic Ra/PL microscopies 2K@14 T to investigate the superradiant emission in van der Waals heterostructures [1], supercooling of nanowater entrapped in graphene wrinkles [2], defects in transition metal dichalcogenides [3], and graphene-substrate interaction [4]. By employing light with intrinsic helicity, valley physics in transition metal dichalcogenides can be addressed [5]. Recently, the helicity-resolved Ra spectroscopy enabled detecting magnetic order in a 2D magnet [6]. Recently, we have also demonstrated that helicity-resolved Ra/PL microscopy is an excellent tool for mapping the spin-lattice coupling and magnetization reversal in various 2D magnets and their heterostructures; selected results will be presented.
REFERENCES: [1] Haider G., Sampathkumar K., Verhagen T., Nádvorník L., Sonia F. J., Valeš V., Sýkora J., Kapusta P., Němec P., Hof M., Frank O., Chen Y.-F., Vejpravová J., Kalbáč M., Adv. Funct. Mater. (2021) 2102196.; [2] Verhagen T., Klimes J., Pacakova B., Kalbac M., Vejpravova J., ACS Nano 14, 15587-15594 (2020).; [3] Verhagen T., Guerra V. L. P., Golam H., Kalbac M., Vejpravova J., Nanoscale 12, 3019 - 3028 (2020).; [4] Verhagen T., Drogowska K., Kalbac M., Vejpravova J., Physical Review B 92, 125437 (2015).; [5] X. Xu, W. Yao, D. Xiao, T.F. Heinz, Nature Physics 10, 343-350 (2014).; [6] B.B. Lyu, Y.F. Gao, Y. Zhang, et al., Nano Letters 20, 6024-6031 (2020).

The study of the optoelectronic properties of single-molecule emitters and their aggregates opens a promising path for the development of technologies related to quantum computing and cryptography, molecular-based memory devices and sensors. The promotion of a single-photon emission can be achieved by a scanning tunneling microscope in a tip-substrate nanocavity, where the nanoscale plasmonic enhancement is able to generate and scatter the electroluminescence signal to the detectable far-field. The so-called STM induced luminescence (STML) technique allows us to get deep insight into the fundamental mechanism behind the molecular electronic and vibronic transitions responsible for the photoluminescence, in addition to providing information on the local density of states with submolecular precision.
Here we present an overview of the experimental setup for the STML experiment approaching two electrofluorochromic molecules (CuPc and ZnPc). A combined scanning probe microscopy (STM-AFM) technique, photon-probe microscopy (STML) and density functional theory (DFT) simulations provided information on the adsorption configuration sites decoupled on a thin NaCl layer on Ag(111), as well as how it can affect the exciton energy and lifetime luminescence. DFT simulations indicate that these changes are related to charge redistribution to different adsorption sites, which ultimately affects the electronic coupling to the environment [1]. In particular, the ZnPc molecules reveal electronic and vibronic signals for two oxidation states (neutral and cation), in a way that the competing excitons can be mapped in real-space with submolecular resolution [2].

Antimicrobial treatment of surfaces is an alternative and a promising way to cope with increasing bacterial resistance to antibiotics, one of the burning problems of our society. Hierarchically nanostructured surfaces with pillar-like patterns have shown antibacterial properties induced by mechanical interactions between the pillars and cell wall. Such structures are present on the wings of multiple dragonfly and cicada species, serving as an inspiration for development of surface-modified polymer materials which would have same pillar nanostructure.
Atomic Force Microscopy (AFM) is a powerful imaging technique which is capable of producing very high-resolution images and topological data in scales of nanometers. The quality of the obtained data is mainly determined by the quality of used AFM tip probe and fine adjustment of measuring parameters and settings of the AFM device. The measurement becomes more challenging if the AFM probe is about to approach soft and elastic surfaces which, due to their properties, tend to bend and vibrate when being measured or stick to the probe tip bottom and hence distort the measurement or even damage the probe. These malfunctions become even more problematic if a dense high-aspect ratio nanopillar network occurs on such surfaces. Yet, the ability to measure materials without necessary surface modifications is a decisive advantage for attempting to use AFM even on such materials. Here we present AFM topography characterization of dragonfly wings nanostructure and their polymer replicas manufactured from various soft polymers.

Novel advanced modes in Scanning Probe Microscopy allow simultaneous measurements of force, probe-sample distance and some other physical quantity, mapping distribution of such measurements across the sample surface. We will present novel tools that can be used for data processing of combined force-volume-energy transfer data sets, improving the quality of measurements by better handling the probe-sample contact. Applications will be related namely to Scanning Thermal Microscopy and conductive Atomic Force Microscopy, where probe-sample contact formation is one of the biggest uncertainty sources.