Seznam abstraktů 2019: POSTEROVÁ SEKCE E

Hierarchically ordered nanostructures can bring several advantages when used as substrates for spectroscopy based on surface-enhanced Raman scattering. Using methods of directed self-assembly we have focused on the preparation of binary direct and inverse opal nanostructures which are made using spheres of two different diameters. In this way, the smaller spheres (or the spherical voids) can occupy the gaps between the larger ones making a fractal-like hierarchical structure. Combining multiple length scales can improve analyte diffusion into the resulting structure and provide a more even distribution of hot spots throughout the substrate at the same time. For the preparation of the direct binary opal structures, we have used the polystyrene spherical particles. Resulting opals were then infiltrated with tetraethylorthosilicate (TEOS) based precursor. After annealing the binary inverse opal structures made of SiO2 were obtained. Silicon dioxide brings two advantages. First one is high thermal stability (and therefore ability to withstand high laser intensities during SERS measurement). The second one is the low intensity of the background signal thanks to the inorganic nature of this material. The final step in the preparation of SERS-active substrates involves the application of a thin layer of appropriate metal e.g. gold or silver using magnetron sputtering or galvanic deposition.

Zinc oxide plays an important role in various industries from electronics to cosmetics. Due to its special characteristics such as antiseptic, astringent and fungistatic properties, anti-corrosion, low electron conductivity and good heat resistance is still the subject of current research. Therefore, friction parameters, compressibility factors, flowability and sensitivity to aeration have been investigated. For this purpose, two nano and one micro-sized ZnO powders were characterized and compared. Experimental work was performed by the Powder Rheometer and Disk Centrifuge. Also a shape analysis of samples were made. The subjects were questions like - how easy consolidated nano/micro ZnO powders will begin to flow or how volume changes as a function of applied normal stress. The first results showed that the slight variations in the shape and size of the ZnO particles could cause differences in the behaviour of the tested powders.

Sarcosine oxidase (SOX) is a flavoprotein and cleaves sarcosine to form hydrogen peroxide, glycine and formaldehyde. Sarcosine is commonly found in muscle, tissues, toothpaste and food supplements. Increased amounts have been found in patients with prostate cancer. SOX is an enzyme suitable for the enzymatic determination of sarcosine. Biotechnological applications require increased stability of used enzymes. In our study, we focused on temperature (5, 15, 20, 30, 35, 40, 50 and 60 °C) and pH-dependent changes (pH 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 and 10.5) in SOX activity. We used native polyacrylamide gel electrophoresis (Native-PAGE) to monitor changes in SOX. Native-PAGE can be sensitive to any process that changes either the charge or conformation of the protein, so they are excellent for detecting various chemical degradations, aggregations, binding changes, acidic, alkaline or denaturing in general. In addition, SOX was bound to the surface of magnetic nanoparticles (SPIONs). When SOX was bound to SPIONs and lyophilized, SOX activity remained unchanged (100 %) after 6 months.

Creation of hydrophobic and hydrophilic surfaces with the spatially selective distribution of grafted organic moieties have great potential in the field of medicine and avionics. The one of more scalable approaches for spatially selective surface modification is based on colloid lithography, which allows large throughput for the subsequent surface grafting and realization of periodic chemical pattern. In this work, we demonstrated the spatially-selective surface grafting by ADT salt with hydrophobic -C8F17 or hydrophilic -COOH groups using following procedure: (i) deposition of PS colloid suspension on substrate; (ii) electrochemical modification of surface with diazonium salt; (iii) removing of PS mask; (iv) second electrochemical modification with diazonium salt. The surface modification through the mask was controlled by PS size, that allowed tuning the area, covered in the first stage of grafting. The modified surface morphology and chemistry was measured by IR spectroscopy and AFM microscopy. Proposed approach allows to effectively decorate surface with different chemical groups in an accurate and precise manner, with additional feature of their mutual “periodic” arrangement.

Surface morphology is a key feature in surface engineering and affects both aesthetics and the function of components. Surface pre-treatment has special significance in coating and modification processes. The pre-deposition treatment of the surface has a significant influence on the durability of the adhesion bonds. The resulting morphology can be influenced by the surface pre-treatment, especially when thin films and nanolayers are deposited. Surface morphology after various pre-treatment methods is studied in this work. Mechanical polishing, electrochemical polishing, chemical etching and ion sputtering were applied to pre-treat the titanium surface. Atomic force microscopy, scanning electron microscopy and light microscopy were used for morphological characterization. Major differences in morphology and roughness were observed, although the thickness of the removed surface layer was comparable in all cases. Typical pre-treatment morphology can be advantageously used in different applications of biomedical engineering (e.g. sliding surfaces, tissue contact surfaces, coating surfaces).

The article deals with the mechanical properties of geopolymers, which were filled micro-and nanoparticles from coke production. As a matrix for the preparation of geopolymer was used materiál Baucis Lk and LNa, commercial product from České lupkové závody Nové Strašecí. It has been chosen a shortened technology using higher temperatures during maturing of the geopolymeru. The influence of particle content
on the mechanical properties of the above-mentioned geopolymers is discussed.

Nanoindentation is currently one of the most popular tools for the study of nanomechanical properties of a wide range of materials such as thin films, nanocomposites and others.
One of the fundamental assumptions used is the approximation of the sample by a flat semi-infinite space. Measurements on a real sample are then designed accordingly. As the dimensions of the sample decrease this may become difficult or even impossible, and the effect of the real geometry of the sample becomes noticeable.
In this contribution we study the effect of the edge of a layer on the apparent modulus. The dependence on the distance from the edge is studied both numerically using simulations and experimentally.

The acid-base centres on the catalyst surface play important role in catalysis chemistry, influencing protons activity in reaction mechanism. The work presents the characteristics of acid-base centres on the vermiculite/α-Fe2O3 nanoparticles composites, when used as catalyst for the chemical recycling of polystyrene to styrene. The iron oxides are often used in chemical/petrochemical application as catalyst. The vermiculite is cheap natural clay mineral, which is commonly used as catalyst support. The vermiculite/α-Fe2O3 nanoparticles composites were prepared by precipitation and calcination at 500 and 700 °C. The acid-base centres on the catalyst surface were characterized by TPD (Temperature Programmed Desorption) method allowing to detect the molecules NH3 and CO2 desorbed from the surface when the surface temperature is increased. The temperature of surface and the peak from desorbed molecules suggest the strength of chemical bond between desorbed molecules and surface. Before desorption, the NH3 and CO2 are adsorbed on the surface of catalysts by chemisorption. The TPD method was supplemented with the laboratory analyses using XRD and SEM.
It has been found that the vermiculite/α-Fe2O3 nanoparticles composite calcined at 500 °C has medium-strong base centres on the surface, although the pure vermiculite is a light acid and pure α-Fe2O3 is a neutral material. For this reason, it can be successfully applied to the depolymerization reaction in conversion to the styrene monomer. The calcination temperature 700 °C did not improve the basicity, but rather led to its suppression.

Nanoparticles get into the biological environment both intentionally and accidentally. In the first case, nanoparticles have been widely investigated in pharmaceutical industry and get to the body intentionally as drugs. In the second case, nanoparticles to the environment accidentally, for example as waste product of textile industry, pharmaceutical industry, metabolic products, etc. The impact of nanoparticles depends on their interaction with the environment.
Characterization of nanoparticles properties plays crucial role in various possible applications. Compressibility properties, which can be accessed by ultrasound techniques, are studied in rather limited number of cases. Silicon dioxide (silica) nanoparticles represent an inorganic material widely used in biomedical fields, especially due to their biocompatibility, stability, high surface area, controllable shape, size and surface charge. The term nanofluid is described as solid-liquid mixture comprising of nanoparticles dispersed in base liquid, e.g. water, buffer or organic liquids, and particle size is smaller than 100 nm.
In this work, LUDOX® colloidal silica (TM-40, HS-40, SM) water suspension of different particle size (22, 12, 7 nm) and concentration range (0-30, resp. 40 wt%) was studied by density and ultrasonic properties measurements. Compressibility and ultrasound attenuation demonstrated untypical non-monotonous concentration dependence which points to specific and concentration-dependent solvation or interaction behavior of the silica nanoparticles in aqueous dispersions.

This project is aimed to study thermal and catalytic properties of nanoparticles. The work includes the synthesis of AgCu nanoparticles by the solvothermal hot-injection decomposition method followed by characterization of prepared nanoparticles using the dynamic light scattering, ultraviolet-visible spectroscopy, transmission and scanning electron microscopes with energy X-ray dispersive spectroscopy and powder X-ray diffraction. Catalytic activity of AgCu nanoparticles was characterized by Knudsen effusion mass spectrometry and was compared with activity of the compact AgCu alloy and with the inert SiO2 nanoparticles. It was found out AgCu nanoparticles have significantly higher catalytic activity than bulk material and inert SiO2 nanoparticles. Surface oleylamine was completely decomposed.
Acknowledgement:
The work has been financially supported by the Czech Science Foundation under the project GA17-15405S and by the Institutional project of Masaryk University MUNI/A/1375/2018.
CIISB research infrastructure project LM2015043 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements at the CF Cryo-electron Microscopy and Tomography.

NaYF4:Yb3+,Er3+@NaYF4 is one of the main compounds between up-conversion phosphors due to its efficient 980 nm absorption, yielding a remarkable green and red up-converted radiation [1]. Typically, the rare earth ions Yb3+ are labeled as sensitizer and Er3+ as activators (blue, green, red nd IR emitter) [2]. The precise green-to-red emission ratio relies on the nanoparticle size, morphology, rare earth concentration and excitation power (e.g. IR laser operating at 980 nm and 1500 nm). Herein, we present a systematic and detailed room temperature micro-spectroscopic study of single NaYF4:Yb3+,Er3+@NaYF4 nanoparticles luminescence. The nanoparticles were synthesized by the conventional co-precipitation method, present elsewhere [3]. Transmission electron microscopy images indicated the formation of uniform and monodisperse nanoparticles with average diameter of 25 nm. Concomitantly, atomic force microscopy study showed sub-25 nm nanoparticles. A detailed up- and down-conversion study was carried out isolating single nanoparticles by drop casting the sample in a thin silicon substrate. A blue diode-laser operating at 405 nm and an infrared laser at 980 nm were simultaneously focused on the sample. Visible emission originating from the electronic transitions from the excited states 2H11/2, 4S3/2 and 4F9/2 to the ground state 4I15/2, was collected by focusing a microscopy objective roughly few millimeters from the surface sample. Finally yet importantly, further improvements on the luminescent yield can be obtained by decorating NaYF4:Yb3+,Er3+@NaYF4@Ag in order to improve UV absorption at about 405 nm via surface plasmon resonance effect. Understanding mechanisms of up- and down-conversion radiation in a single nanoparticle combined with plasmon effect may be of the great potentiality to design robust nanomaterials for phosphors, biosensor, luminescent layers for solar cells and others.

[MEn3]XO4 (M = V, Ni, Co, Cu, Fe; X = Cr, Mo, W, S; En - ethylenediamine) is a representative of a wide structural class of compounds with complex cations [MEn3]2+ and tetraoxoanions. These compounds are promising precursors for synthesis of metal and metal-carbon nanomaterials. X-ray diffraction measurements of complex salt [NiEn3]WO4 (1), [NiEn3]MoO4 (2) and [NiEn3](MoO4)0.5(WO4)0.5 (3) monocrystals showed that they are isostructural. So, existence of a wide range of phases [NiEn3](MoO4)1-х(WO4)х (x = 0-1) is expected. Formation of nanocrystal phases involving Ni, Mo and W may occur at their thermal decomposition. The presence of C atoms in En-ligand under certain conditions can lead to the formation of carbide phases.
Thermal decomposition 1, 2, and 3 were performed at the wide temperature range (350-1150°С) and reaction time (1-10 min) at presence of LiH in the He atmosphere. According the data, obtaining by the method of electron microscopy, phases in nanocrystalline state were formed in all cases. Studying of the phase composition was carried out using the diffractometer Bruker DUO (CuK radiation, CCD detector, Debye-Scherrer geometry). It is show that when 1 is heated to 860°C, the phases NiСх, W1-хNix, Ni1-хWх, Ni2W4C and Ni6W6C were formed. Similarly, for 2 forming of Mo2C and MoNi4 at the temperature 1048°C within one minute was shown, Ni2Mo4Cx phase was obtained at holding time increasing. Thermolysis of [NiEn3](MoO4)1-х(WO4)х products in wide range of phases with more complex composition.

Voidage of a fluidized bed is a primary property of fluidized systems when determining the minimum floating velocity. The air flow rate in the fluidized bed (or in the fluid layer of the material) increases with diminishing bed voidage. This paper is devoted to fluidized bed voidage calculations for a fluidized bed consisting of spherical particles having different diameters and in differently shaped polygonal fluidized bed cells possessing different characteristic particle floating velocities. For testing purposes, voltage of fluidized bed was experimentally measured and subsequently modelled by simulation using the Rocky (DEM) software.

Combustion methods are a promising strategy for the lanthanide oxide nanomaterials preparation. They are environmentally friendly, they have feasible experimental setup and can be easily upscaled. As a part of our broader research dealing with amino acid-nitrate processes, several samples of the Gd2O3, synthesized with four amino acids (alanine, glycine, proline, and serine) were prepared to observe an influence of amino acids on the final product’s nature and morphology. All of the four samples were prepared via thermal decomposition of a transient complex formed in situ from Gd(NO3)3·6H2O and selected amino acid. The resulting products were characterized by the X-ray powder diffraction analysis, which demonstrated an influence of amino acids on the crystal structure of the final Gd2O3 nanocrystallites. The elemental composition and morphology of the samples of Gd2O3 were examined by the scanning electron microscopy with energy dispersive X-ray spectroscopy. We also measured particle size and particle size distribution as all final products (Gd2O3) had tendency to form agglomerates. Fourier-transform infrared spectroscopy and X-ray powder diffraction analysis revealed that glycine and proline, used as an organic fuel, yields the cubic structure of Gd2O3 nanocrystallites. 610

Luminescent silicon nanocrystals (Si NCs) represent a promising alternative to the conventional II-IV and III-V semiconductor NCs, especially for biological applications. Si NCs are biocompatible and exhibit tuneable emission in the NIR region. Moreover silicon is naturally abundant and fabrication methods for Si NCs have been well established in the past decades. However, a rather low spontaneous radiative rate can limit the use of Si NCs in some cases.
One of the possible strategies for photoluminescence enhancement is combining the fluorophore with plasmonic nanostructure, whose strongly confined electric field and increased local density of states can support the excitation and emission efficiency of the fluorphore. In our study gold nanorods (Au NRs) were chosen to be the plasmonic part of the system due to their excellent optical properties, biocompatibility and straightforward synthetic protocols that yield good quality particles in big volumes.
Even though the plasmon enhanced luminescence of semiconductor NCs has been studied previously, there are still some crucial parameters that remain challenging to control, such as the separation distance between the NCs and plasmonic particles, distance between the neighbouring NCs, excitation/emission-plasmonic wavelength match and surface chemistry of the plasmonic particles. Our study aims at optimization of the fabrication process that leads to well-defined AuNR-SiNCs hybrid structures. We first grow a silica shell on Au NRs, which then serves as a very stable and optically transparent spacer between Au NRs and Si NCs. The resultant colloidal solution of these hybrid particles enables us to study the mechanism of luminescence enhancement even on a single particle level.

Two-dimensional colloidal nanocrystals have recently revealed a great potential as optical gain media due to their remarkable optical properties. Besides controlling the size and shape of semiconductor nanocrystals the variation in the chemical composition is another way to control the optical properties of nanomaterials. It is of especial interest to use here the cationic substitution reaction instead of direct synthesis from a Pb precursors, since we may start from cadmium chalcogenide nanocrystals of well controlled size, shape and crystalline structure. So, the cation exchange reaction of cadmium by lead in well-studied colloidal CdSe and core/wing CdSe/CdS nanoplatelets has been examined by absorption and photoluminescence spectroscopy.

The local mechanical properties of FeAl - based alloys were studied using nanoindentation techniques. Sharp Berkovich indentor was used to perform load-controlled nanoindentation experiments on the studied sample. Hardness and elastic modulus maps were created on the basis of the indentation tests carried out in different grains.High resolution topography, storage modulus and loss modulus maps were collected simultaneously on the studied samples in a purely elastic regime without any residual deformation.
The modulus mapping method combines the in-situ imaging capabilities with the ability to perform nanodynamic mechanical analysis. During the imaging process, the system continuously monitors the dynamic response of the sample to the oscillating load as a function of the position. Therefore, at each image pixel, the storage and loss moduli are found if the geometry of the indenter is known. The modulus mapping measurements were performed by applying a constant force of 1-3 μN and an oscillating force with amplitudes of 0.3-2.0 μN in frequency range from 150 to 300 Hz.
The local mechanical property mapping results were completed with hardness and elastic molus maps obtained using grid indentation tests at nanoscale.

All-inorganic perovskite nanocrystals with chemical formula CsPbX3 (X = Cl, Br, and I) attract much scientific attention since they possess unique optical properties, such as high extinction coefficients and values of emission quantum yield, together with ease of their synthesis and tunability in the chemical composition. However, these nanomaterials are still far from their large-scale applications since they lack stability. Here, it was shown that the use of a nanoporous glass matrix allowed obtaining the samples with blue, green, and red perovskite nanocrystals possessing reproducible optical characteristics which are almost similar to that of their colloidal solution. Such a matrix also prevented the fast degradation of nanocrystals both at the storage in ambient and under UV-light exposure and/or in the conditions of increased humidity.

The synthesis and application of metal and ceramic nanoparticle are significant subject in science and engineering. The metal nanoparticles such as gold, silver, and copper nanoparticles have more application in material science, nanomedicine, electronic, photonic, and art. One of the green method for preparation of metal nanoparticles is laser ablation technique that offers a unique tool for nanofabrication of nanoparticles. In this work, gold colloids were prepared by pulsed laser ablation of high purity gold plate immersed in deionized water and 10µM NaCl solution. After ablation process we study the change in the size distribution of nanoparticles after the ablation process for a month.

Zirconium oxide (ZrO2) is a widely utilized inorganic material with excellent dielectric, optical, and biocompatible characteristics. The properties and areas of the ZrO2 applications can be further broadened by making the material nanostructured. In this work, anodic ZrO2 nanostructured films were developed and characterized by scanning electron microscopy. The films were prepared by anodizing magnetron-sputtered Al/Zr bilayers in two regimes: galvanostatic/potentiostatic anodizing in (COOH)2 and H2SO4 solutions (anodized films) and that followed by the high-speed reanodizing to a significantly higher anodic voltage (reanodized films). The growth of a porous anodic alumina (PAA) layer followed by PAA-assisted oxidation of the Zr underlayer was achieved. The anodized films consist of arrays of self-organized spatially ordered ZrO2 nanohillocks while the reanodized films comprise arrays of vertically aligned ZrO2 nanorods. The growth of amorphous ZrO2 nanohillocks and nanorods within the alumina pores via migration of Zr4+ cations is a unique situation for anodic films on zirconium, which normally grow crystalline and by O2- anion transport at the oxide/metal interface only. The achievement is a milestone towards understanding the ion transport during the PAA-assisted anodization of valve metals with low cation transport numbers

In the present work we focused on the development of a low pressure capacitively coupled radio-frequency PECVD reactor for preparation of plasma-polymer thin films from organosilazane precursors. The dependence of the film growth from hexamethyldisilazane (HMDSZ, SiN2C6H19) and oxygen containing mixtures on the deposition parameters was studied. The time evolution of the negative self bias voltage on the thin film growth was studied. It was found, that the changes in the self bias voltage significantly influenced the surface structure and the properties of the growing films. The mechanical properties of the films were studied using nanoindentation technique and the surface structure was studied using atomic force microscopy (AFM).

In the present work plasma-polymer nanocomposite thin films were prepared under dusty plasma conditions in capacitively coupled RF discharges. The main focus was on the study of the formation of the organosilicon plasma polymers and their growth. The plasma polymers were grown heterogeneously in form of polymeric particles arising from the discharge volume which incorporated into the amorphous organosilicon polymeric film growing on the silicon and glass substrates. The created nanocomposite structure had very beneficial influence on the film properties. The films showed very interesting mechanical and surface properties. Variation in deposition conditions enabled us to vary the surface free energy of the films. The mechanical properties of the films were studied using nanoindentation technique and the surface structure was studied using atomic force microscopy. The atomic composition and chemical structure of the films were studied studied using XPS and FTIR techniques. The surface free energy of the films was studied using contact angle measuring techniques.

Self-assembled monolayers (SAMs) has recently received much attention because of their wide range in applications such as layers in biosensors, electronic active layers or interlayers in organic electronic devices like organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), organic thin film transistors (OTFTs). Photolithography is a basic and long established technique used in the preparation of processors and other electronic components. This paper deals with patterning of self-assembled monolayers prepared on gold and silver layers using photolithography. Firstly, the prepared self-assembled monolayers were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier-transform infrared spectroscopy (FTIR). Subsequently testing patterns according to the resolution chart test were exposed by UV lithography. These prepared patterns were characterized by optical microscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM).

Metal and organometal halide perovskites, an emerging class of direct bandgap semiconductors, have attracted great attention lately. Lead halide perovskites were recognized as promising candidates for future lighting applications, due to their high quantum yield, narrow full width at half maximum (FWHM), and wide color gamut. Nonetheless, the toxicity of lead induces new approaches such as obtaining lead-free perovskites and further investigation of their stability and optoelectronic properties.
In this work is presented a study of lead-free perovskites (CH3NH3)3Bi2I9 film formation for a further application in optoelectronic devices. The experimental part consists of the formation (CH3NH3)3Bi2I9 films and a treatment part. First part has been performed with a quite popular spin-coating approach that provides accessibility and simplicity of the sample’s preparation. Secondly, a liquid nitrogen treatment has been carried out, afterward was investigated the effect of this treatment on the lead-free perovskites films.

Nanocomposite polymer coatings based on an organic matrix and incorporated inorganic nanoparticles are important materials due to their unique optical, mechanical, magnetic and optoelectronic properties. The optical properties can be studied using well established spectroscopic reflectometry. However, to increase lateral resolution and speed of the data acquisition another optical technique - spectroscopic imaging reflectometry can be chosen.
In this contribution, we concentrated on optical characterization of amorphous SiOxCyHz composite films. The thin films were prepared in dusty plasma by radio frequency (13.56 MHz) plasma-enhanced chemical vapour deposition. The optical properties of the films and maps of thickness distribution across the films were determined using spectroscopic imaging reflectometry. To increase reliability of the results, hybrid metrology algorithms were used. For this approach, another sets of data were acquired by other measurement techniques such as large area atomic force microscopy or scanning thermal microscopy.

Among the numerous organic semiconductors, metal phthalocyanines (MPc) are of particular interest because of their high thermal and chemical stability combined with unique electronic properties. It is well known that the choice of deposition conditions can significantly affect the process of growth and molecular organization of thin organic films that importance for their use in electronic devices. Among a wide variety of factors influencing the structural of phthalocyanine films, the effect of an external magnetic field is also reported.
The aim of this work is a comparative X-ray diffraction study of TiOPc PVD-layers obtained by thermal sublimation on a glass substrate (Knudsen chamber, vacuum 1х10-5 mm Hg, 450 ℃) in a magnetic field (sample M) and without it (sample O). The initial TiOPc powder was a II - triclinic modification (hereinafter IIt-TiOPc).
XRD measurements were carried out using a ShimadzuXRD-7000 diffractometer (Bragg-Brentano configuration, CuK line as X-Ray source, Ni filter). Comparing the obtained diffractograms with the theoretical ones, it was found that in both cases (M and O), the IIt-TiOPc PVD-layers are mainly oriented along the (010) plane. A study of the structural organization of the samples shows that the angle between the plane of the molecule and the substrate is 63 °. The integral intensity of reflection from the (010) plane of sample M is 7 times higher than the intensity of the same reflection of sample O, and the half-width (FWHM) of the peak (010) M is 2 times less than that of (010) O. The effect of annealing (180 ℃, 1 hour, in air) of M and O samples in a magnetic field and without it was studied.
Thus, in this work, the use of a magnetic field to obtain PVD-layers of TOPc with improved crystallinity was demonstrated.

Plasma-polymerized SiOxCyHz thin films have been playing an important role in many research studies due to their wide range of applications. These materials are perspective for industrial applications as protective coatings of metals or plastic substrates, anti-reflection coatings for solar cells, low-k dielectrics for microelectronics, water-repellent barrier films etc. Materials based on organosilicon precursors prepared by PECVD technique have become interesting for bioapplications in recent years as well due to their ability to optimize protein adsorption and cell attachment. These coatings have a great potential e.g. in BioMEMS microfabrication or treatment of biosensors and surfaces of medical implants.
In the present study, low pressure RF capacitive coupled discharge in mixture of trimethylsilyl acetate (TMSA) monomer with oxygen or argon was used to create hydrophobic SiOxCyHz coatings. This study is focused primarily on research of properties of resulting coatings (chemical composition, mechanical properties, optical properties, surface wettability and surface structure) in dependence on discharge parameters. Properties of created thin films were examined in dependence on the ratio of TMSA monomer and carrier gas flow rates during the deposition process. Influence of used carrier gas (O2 or Ar) on growth of TMSA-based plasma polymers is discussed in this study as well.

The diffuse coplanar surface barrier discharge generated in reducing atmosphere presents a novel approach to polymer surface modification. Various gas mixtures of hydrogen in nitrogen (0%-100%) were tested on flexible polyethylene terephthalate (PET) foil treated in roll-to-roll configuration. The water contact angle and surface free energy were measured in dependence on treatment time and used gas mixture. The changes of surface morphology were observed by scanning electron microscopy and chemical composition of the surface was analysed with X-ray photoelectron spectroscopy. We achieved hydrophilic surfaces in gas mixtures containing predominantly nitrogen what was associated with an increase of nitrogen content on the plasma-treated PET surface. The polymer surfaces were etched mostly in pure hydrogen plasma.
ACKNOWLEDGEMENTS: The authors would like to thank Dr. Monika Stupavská for acquiring the XPS data. The authors would like to acknowledge financial support from the project TJ01000327, funded by Technology Agency of the Czech Republic and project MUNI/C/1673/2018, funded by Grant Agency of Masaryk University.

The interest of phosphorene as 2D material is permanently growing because of its biocompatibility and excellent mechanical, electrical and optical parameters. It have been used in many applications, e.g., photodetectors, energy storage devices, modulators, insulators or sensors. In physiological conditions, BP degrades into non-toxic phosphite, phosphate, and other PxOy species. Its biodegradable and biocompatible properties could be used therapeutically [1].
Herein, we report for the first time electrochemical performance of phosphorene functionalized by azide benzoic acid. A covalent combining few-layered black phosphorus (FL-BP) with benzoic acid can function as a bridge between FL-BP and biomolecules. The functionalized phosphorene results in improved dispersancy in aqueous solutions.
FL-BP/Ar-COOH was synthesized in a deoxygenated polar aprotic solvent like as dimethylformamide at temperature equals 140ºC. The efficient functionalization of BP flakes was revealed by infrared spectroscopy. The cyclic voltammetry and electrochemical impedance spectroscopy measurements were carried out in NaCl solution containing reference redox systems: [Fe(CN)6]3−/4−.
Moreover, the benzoic groups enhance electric conductivity delivering fast direct electron transfer. Modified FL-BP works as surfaces for determination of organic molecules, e.g., nucleic acid bases or peptides and proteins, while it offers the promising possibility for biosensing. ACKNOWLEDGEMENTS: This work was supported by the Polish National Science Centre [2016/22/E/ST7/00102]; and the National Centre for Science and Development [347324/12/NCBR/2017]. The DS funds of the Faculty of Electronics, Telecommunications and Informatics of the Gdansk University of Technology are also acknowledged. REFERENCES: [1] YI, Ya, YU, Xue-Feng, ZHOU, Wenhua, WANG, Jiahong, CHU, Paul. K., Two-dimensional black phosphorus : Synthesis, modification, properties, and applications. Materials Science and Engineering R. 2017 vol. 120, pp.1-33.

Polymer - metal based materials with unique 3D structures can find various applications in biomedical field. This study has focused on silver colloid influence to unique polymers structures prepared through electrospinning and electrospraying.
We have prepared hybrid material in two steps: (1) silver nanoparticles have been prepared by phytosynthesis using Tilia sp. leachate and (2) incorporation of nanoparticles into the polyvinyl alcohol (PVA) matrixes prepared by electrospinning and electrospraying.
Bottom-up phytosynthesis enables nanoparticles´ formation and its presence can directly influence technological steps during PVA matrix preparation. We have achieved successful preparation of PVA fibers and spheres while scanning electron microscopy with EDS analysis determined fiber/sphere uniformity with the presence of silver nanoparticles.
Electrospinning/spraying methods can be suitable methods for diverse compounds´ incorporation, however, it is always necessary to take into account the possible interactions between compound and carrier polymer.

Inorganic submicron fibers (ISF) are nowadays widely studied material. Usually, they are produced by 2-step process. First, the composite metal-organic fibers are produced from polymer matrix and metallic precursor, typically alkoxides or salts by standard spinning techniques. After this, prepared composite fibers are thermally calcinated to remove polymer and form ceramic fibers. In this study, we used low temperature plasma generated at atmospheric pressure using Diffuse Coplanar Surface Barrier Discharge (DCSBD) to eliminate organics from the composite fibers before thermal treatment to reduce the time required for thermal calcination of Al2O3 fibers. This plasma pre-treatment enables using significantly higher heating rates compared to standard calcination without damaging the fiber structure.

In this work, the electrospinning process was used for the preparation of ceramic nanofibres from PVA/Al(NO3)3·9H2O precursor solutions. Six solutions with different weight concentrations were prepared and nanofibres from each solution were made. Precursor nanofibers were treated in DCSBD plasma (diffuse coplanar surface barrier discharge) for 10 minutes. Later fibres were thermally treated in furnace. Obtained calcinated nanofibers were analysed by FTIR analysis, scanning electron microscopy and thermogravimetry.

Silica nanosphere with a diameter of 10-15 nm were organized into fibers with a lenght of 15 mm and an aspect ratio of 100 by self-assembly in 1,4-dioxane. Dioxane causes a positive zeta potential on the silica surface thus silica in dioxane may behave as an acceptor (base catalyzer) causing decomposition of dioxane to acetaldehyde and its consequent polymerization into oligomer or polymer (polyoxyethylene) chains that bond the particles together. This process was proved using a thermogravimetric analysis which showed that the amount of polymerized dioxane is in the rang 2-3.5 wt. %. Composition of the polymerized dioxane was elucidated employing FTIR. The formation of fibrillar structures was driven kinetically during solidification. The size of the fibers was controlled by the drying rate. Fast-drying results in longer and thinner fibers. Nanosilica fibers can also be formed in a polymer matrix (e.g. polycarbonate) via the solvent-casting method. Formation of fibers in-situ in a soft rubber polymer matrix in one-step processing can provide a polymer reinforcement at two hierarchical levels - at the nanoscale by immobilizing polymer chains due to the presence of nanoparticles and the microscale by strain transfer to the fibers. Elastic modulus of the fibers was determined by wrinkling technique by compression on the elastic surface and by thermal treatment in the polycarbonate matrix. Both techniques showed modulus 43-46 MPa.

Nanofiber’s morphology features (diameter, pore size, roughness) together with mechanical properties and biocompatibility are crucial for the evaluation of nanofibrous web’s structures properties. Surface’s morphology strongly affects among all the physical, mechanical, and biological properties of the web’s structures. A detailed characterization of scanning electron microscopy images is decisive and widely used. Image analysis include most often the determination of fiber amount and their diameters on the monitored area; occasionally also the porosity and pore size determination; and very rarely the other parameters like linearity/curvature rating or orientation of fibers etc. Characterization by confocal microscopy is not yet commonly applied. However, the detailed observation of the surface and its evaluation bring many advantages, especially surface roughness determination but also the surface kurtosis and surface skewness etc. This work briefly summarizes the evaluation methods applicable for morphological characterization of nanofibers from SEM and confocal microscopy; and bringing closer insight for possible prediction of physical, mechanical, and biological properties of the nanofibers.

The conductive composite materials constitute a new class of materials with a broad spectrum of applications. They are obtained by the incorporation of conductive inclusions within an insulating polymer matrix. They have both high electrical conductivity and low density. This work focuses on the use of PMMA as a matrix. This thermoplastic is known for its high transparency, its clarity, its exceptional optical properties, very smooth and glossy surface appearance, its excellent resistance to atmospheric agents and its excellent resistance to ultraviolet rays and corrosion. The PMMA was synthesized by industrial process and the composites were prepared by in situ polymerization at different percentages (0.1, 0.3 and 0.5 %) based on PMMA as a matrix and the polyaniline doped with malic acid in one step (PANI) as a filler because it seems to be very interesting to obtain the best compromise between stability, conductivity, structural, optical properties and low cost in the goal of having conductive films having good optoelectronic properties at the same time and which can be used in areas such as integrated photonics, sensors and electronics measurements and optoelectronics for optical telecommunications. The obtained composites were characterized by several techniques (FTIR, UV, DRX, TGA, DSC and electrical conductivity).

The ZrB2-MoSi2 coating modified by Y2O3 and Al was prepared on a carbon/carbon composite substrate by a new multi-chamber detonation accelerator (MCDS). The thickness of deposited coatings ranged about 90-130 m. The powder containing 41 mol.% of ZrB2, 5 mol.% of MoSi2, 1 mol.% of Y2O3 and 53 mol.% of Al (1-25 μm) has been used as the feedstock material to deposit a dense layer. The structural-phase state of the coatings was characterized by X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy. The ZrB2-MoSi2 coating was well-adhered with carbon/carbon composites. The coating displayed compact microstructure with porosity lower than 1%. It was established that phase composition of ZrB2-MoSi2 powder under the influence of high temperatures and the atmosphere of detonation products changes with the formation of a complex heterogeneous structural-phase state in the coatings. As-sprayed coating consisted of t-AlZrO2, fcc-Al, m-ZrO2 and m-SiO2. ZrB2-MoSi2 coatings are characterized by the presence of nanodispersed particles. The most of the powder particles were melted and formed lamellar-like structure typical for thermally sprayed coatings. But small amount of partially-melted areas has non-uniform structure, ranging from lamella to sphere with a size range of 0.05-1.5 μm.

Molecular self-assembly is a key process both in biological and material science. The control of the molecular organization is problematic and the spontaneous tendency of the molecules to organize therefore seems to be an appealing tool for fabrication of complex nanostructures.
The focus of our research is a surface self-assembly of large π-conjugated macrocycles. The macrocycles consist of a triangular core of interconnected helicenes which are surrounded by bulky trityl groups. The molecules adsorbed on HOPG surface were studied using ambient Dimension Icon AFM. The PeakForce QNM mode and a careful tip selection turned out to be crucial for obtaining high quality images. Under favourable conditions, we were able to reach submolecular resolution, and in some instances even faintly visible internal structure and hexagonal perimeter of the 3 nm molecules were observed. The experiments also revealed highly dynamical nature of the adsorbed molecules, as demonstrated by a tip-induced reorganization of the monolayers.
In order to better interpret the obtained AFM images, our attention turned to molecular dynamics simulations. To perform the simulations at room temperature and keep the system in a stable configuration, the model system was first optimized using the technique of simulated annealing. Subsequently, we tested various starting configurations to look for the most probable surface packing of the molecules. The results confirmed high surface mobility of the macrocycles and its ability to form organized arrays, both observed during our AFM experiments.

ZnO nanocrystals find various applications in physics, optics, medicine, and electronics. For the practical deployment of ZnO nanocrystals to construct electromechanical and optoelectronic devices, it becomes necessary to fully understand their morphology and to precisely predict their external appearance. The balanced corridor between external shape of a crystal and its internal arrangement of atoms opens the future of the shape selective applications of ZnO nanoparticles in tribo-/piezo-electric nanogenerators and in drugs for therapeutic interventions.
Here, external morphology of ZnO crystal is deduced from its internal crystal structure by considering the propagation vector of center of mass of the molecular basis (namely HNB vector; Harsh−Nidhi−Binay) in the ZnO lattice. Also, two of the well established models namely Bravais−Friedel−Donnay−Harker model (BFDH), Hartman−Perdok (HP) periodic-bound chain (PBC) vectors model were used to predict crystal morphology of ZnO crystal.
Using the interplanar spacing dhkl and space-group symmetry operation, the BFDH model predicted the external shape of ZnO nanocrystal to be hexagonal plate with (001) & (00-1) planes being largest visible.
Based on the number of PBC vectors parallel to different planes in ZnO crystal lattice, HP model predicted the external shape of ZnO nanocrystal to be a hexagonal prism with hexagonal-truncated pyramids at both the ends. The morphological importance of six symmetric planes forming the hexagonal prism was predicted to be largest.
Considering the propagation vector of center of mass of the molecular basis present in ZnO crystal lattice, HNB model predicted the external shape of ZnO nanocrystal to be largely grown hexagonal-truncated pyramids at both the ends with very less grown hexagonal prism in the middle.
Results suggest that the morphology predicted by BFDH law, HP theory and HNB theory completely agrees with the actual grown ZnO crystal shape by different research groups as well as proves the diversity in the morphology of ZnO nanocrystals.

Atomic force microscopy is one of the key techniques for measurements of dimensions and other properties in nanoscience and nanotechnology. To measure the interaction between probe and sample, typically a flexible tip holder (cantilever) is used and its deflection is measured using an optical pickup. This has many limitations if we want to know the tip position accurately. As an alternative, fiber interferometry can be used to get much more accurate tip position information, which is important namely in nanomechanical studies. In this contribution we present a novel three fiber interferometers based AFM head for even more accurate and faster measurements and show its capabilities on reference samples measurements. Measurements of force-distance curves on different materials and with different probes will be demonstrated and metrological traceability of the method will be discussed.

Nanomaterial powders and colloids are already a large industry and are expected to continue to grow rapidly. In the context of risk assessment associated with nanomaterials, characterization of nanoparticle size and morphology is required. Until now, the best method giving direct access to these parameters has been electron microscopy (EM), in particular, transmission electron microscopy (TEM). Although this method is widely used, several issues are highlighted such as cost, maintenance, sample representativity and damage for sensitive materials. Low-voltage transmission electron microscopes (LVTEMs) could be an alternative approach to solve some of these issues. This paper presents a first comparison between a benchtop LVTEM and a conventional device to determine the number size distribution of the constitutent particles of two polydispersed industrial powders (TiO2 and SiO2) with particle sizes close to 100 nm and two colloids referenced for their particle size (ERM FD 304 and NM 300 K). The samples were prepared with an optimized deposition protocol involving glow discharging and Alcian blue solution pre-treatment on the EM grids. The benchtop LVTEM produced a rather good resolution and the relative differences obtained for the median diameters D50 are generally within ±15 %. On the basis of these results, benchtop LVTEM could be promoted for identifying nanomaterials within the framework of risk assessment strategy.

Nanoindentation has become a popular tool for the exploration of mechanical properties of materials at the nanoscale. However, calibration and traceability issues are often neglected, making the direct comparison of results between different instruments difficult. The direct calibration of the sensors is challenging and requires dedicated instruments leaving indirect calibration as the only option to ordinary users. However, indirect calibration compares only the resulting hardness or modulus of the reference sample and the measured sample. Therefore, it cannot distinguish the source of errors, such as errors in the depth and load sensors, errors in the reference sample properties, contamination of the tip or sample, wear of tip and others.
In this contribution we explore the possibility of using measurements of indents by atomic force microscopy for the verification of the depth sensor. Measurements for different nanoindentation devices are presented and compared with a focus on the uncertainties of the method.

This work is aimed to evolve route for preparation of metal grids useful for analysis of bio-samples by cryo-electron microscopy. The main goal was to find out reaction conditions for reproducible modification. Thin copper layer was sputtered on gold grid and then reacted in alkaline solution of ammonium persulfate for various time. Sputtering ensures measurable and controllable amount of copper on inert grids. Copper was oxidized to form nanowires of CuO and Cu(OH)2 which rapidly increase hydrophilicity and rate of removing water from sample. Modified grids were characterized by scanning electron microscopy and powder X-ray diffraction for describing of nanowires growing during various reaction time and application of different copper layer thickness. It was found out that nanowires growing is providing in two steps. In the first step nanowires are constantly growing from metal layer and subsequently are sintering into nanoplates and nanowire-haired structure is gradually degraded.
Nanowired grids were successfully tested in preparation of bio-samples for cryo-electron microscopy characterization.
ACKNOWLEDGEMENTS: This work is financially supported by TA CR (project TN01000008) CIISB research infrastructure project LM2015043 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements at the CF Cryo-electron Microscopy and Tomography.

We have employed two dimensional electronic spectroscopy (2DES) to study fast energy relaxation in near-band edge states of colloidal CdTe nanodots at both room temperature and 77K. 2DES technique has two main advantages: first, it allows determination of which state was excited by a very short (and therefore spectrally broad) laser pulse even if it covers multiple possible transitions. Second, the resulting two dimensional spectra directly indicate coupling of energy states by presence of cross-peaks. This, together with sharpening of spectral features at low temperature conditions,
allows drawing a clear picture of both incoherent (e.g. energy transfer) and coherent (e.g. coupling of excitons and phonons) dynamics of the system. The goal of the study is to compare the resulting data with outputs of (single) nanodots measurements by AFM and microspectroscopy to gain information about interactions of nanodot core with its surface passivating layer.

This contribution is focused on the optimization of passive microrheology using fluorescence correlation microscopy (FCS). This technique is a very accurate analytical tool for the study of soft-matter systems, but there are only few of published articles on FCS usability for microrheology. For this reason, some workflow had to be optimized.
In this study, the influence of the nanoparticles size, the usable range of environmental viscosity and the applicability of the technique to hydrogel systems was determined. Fluorescently marked nanoparticles in the range of 10-100 nm were selected as microrheological probes. A glycerol solution of various concentrations was chosen as a model viscosity medium. The obtained viscosity limit values for the nanoparticles were verified by the MSD (mean square displacement) motion modelling. The values obtained from the autocorrelation curve were converted by the MATLAB software to MSD curves. The influence of experimentally obtained parameters on the shape of this curve was observed, where the number of particles and the autocorrelation function had the most significant influence.
For gel experiments, aqueous solution of agarose in various concentration was selected based on the fact that it is one of the most studied hydrogel systems. The effect of gel age on the diffusion coefficient was tested, the most valid values were obtained within one week of gel preparation. Furthermore, the effect of gel concentration on the pore size was investigated. The value of the diffusion coefficient proved that it is a very inhomogeneous system where the pore size cannot be accurately determined.