Poster Session II
Thursday, 16 September
15:30-16:30 PM (CEST)

Author

Dr. Samia Aslam

Ekaterina Kosareva

Daniel Steinbach

Thi Quynh Tran

Laia Pasquina-Lemonche

Solène Lecot

Gnanachandran Kajangi

Assoc. Prof. Talgat Sharipov

Qiwei Hu

Dr. Iuliana Stoica

 

Dr. Andreea Irina Barzic

 

Arkadiusz Foks

Krishnaveni Palanisamy

Sy Hieu Pham

Claudiu Hapenciuc

Assoc. Prof. Csarnovics István

Poster Title

SPM imaging based morphological study of novel semiconductor nanocomposites for optoelectronic applications

 

Scanning Probe Microscopy Study of Polymer-Coated HMX Particles: From Surface to Bulk Properties

C-AFM measurements on [Rh2(acam)4pyz]n

Deciphering the effect of matrix stiffness on cell mechanics

The bigger picture by AFM: peptidoglycan structure of Gram-positive bacteria and its destruction by antibiotics

Modeling Single Molecule Force Spectroscopy - AFM mode by Steered Molecular Dynamics simulations: Effects of silane monolayers on protein adsorption and on analyte recognition

Mechanical and Microrheological properties of Bladder Cancer Cells: from Single Cells to 3D Multicellular Spheroids

SPM of DNA with a homonucleotide sequence

Investigating Triboelectric Charging by a combination of AFM-based Force Spectroscopy and Kelvin Probe Force Microscopy

Advanced morphological and statistical analysis of laser induced micro/nano multiscale surface relief gratings on azo-polyimide films

Mechanical alteration of the morphological features of a polyimide and their impact on interfacial compatibility

 

Study of nanostructures formed by the interaction of highly charged ions with gold nanolayers using atomic force microscopy

Solid electrolyte interphases at Hard Carbon anode materials via Scanning Probe Microscopy Techniques

Nanoscale current spreading analysis of electrodeposited silver nanowires network by using the conductive-atomic force microscopy

Quantitative evaluation of thermal conductivity measurement error in Scanning Thermal Microscopy induced by an asymmetry in the probe-sample contact point

Plasmonic nanostructures for photonic applications

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Dr. Samia Aslam: "SPM imaging based morphological study of novel semiconductor nanocomposites for optoelectronic applications"

COMSATS University Islamabad, Lahore Campus, Pakistan  

Scanning probe microscope imaging is a superior and useful technique to investigate the morphology of novel materials under investigation for various optoelectronic applications including solar cells, fuel cells Light emitting diodes (LEDs) and supercapacitors. These materials are employed by quoting them as thin film on an electrode substrate during device assembly. The morphology of these thin films plays a critical role in dictating various physical processes within the materials such as carrier transport and recombination pathways. The morphological study includes an assessment of roughness of the electrode, film thickness, grain boundaries, grain density and grain size distribution which play crucial role in tuning the optoelectronic properties of these novel materials. Semiconductor, carbon, and graphene-based nanocomposites are being widely investigated now a days being tangible candidates for next generation optoelectronic devices offering superior and promising electronic and optical properties suitable for such devices. In this work, group II-VI semiconductor, graphene, and carbon-based nanocomposites have been studied as electrode materials using atomic force microscopy (AFM) non-contact imaging techniques. The 3-D topography, grain size distribution, roughness and grain density has been investigated as a function of experimental parameters, precursor concentration and composition.

An influence of the morphological tuning of the nanostructures on efficiency of various optoelectronic device applications including solar cells ,supercapacitors and LEDs has been reported.

 

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Ekaterina Kosareva: "Scanning Probe Microscopy Study of Polymer-Coated HMX Particles: From Surface to Bulk Properties"

Semenov Institute of Chemical Physics, Russia 

HMX (C4H8N8O8) is a key component of modern high-energy compositions due to its high thermal stability, density, and energy content. However, its high mechanical sensitivity and electrostatic charges accumulation in bulk explosives during handling, producing, transferring, sieving, and storage considerably increase the hazardous level, especially for the small particles. Therefore, the improving of its safety is a highly actual task. One of the ways to decrease the hazardous level of the HMX particles is to coat them with polymer. In this study, HMX particles are coated with six various polymers using the supercritical CO2-based anti-solvent method (SAS). Combination of atomic force microscopy (AFM), AFM-based force spectroscopy and Kelvin probe force microscopy (KPFM) methods was applied to investigate coating-induced changes of the particle surface. Obtained local properties were compared with several bulk properties of modified HMX to find a possible relationship. The considerable decrease in the sensitivity to impact and friction of polymer-coated HMX particles have been found for several polymers that provide the surface roughness and local adhesion force increase with the polymer concentration growth. Moreover, the KPFM results revealed the modified HMX particles to demonstrate the surface electrical potential decrease, which in turn results in the significantly improved bulk flowability. The established relationships are important in predicting of the bulk properties of energetic materials by using the local analysis of the particle surface with scanning probe microscopy.

 

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Daniel Steinbach: "C-AFM measurements on [Rh2(acam)4pyz]n"

Institute of Physical Chemistry, TU Bergakademie Freiberg, Germany

Due to their potential use in sensor devices, as electrode coatings and in other upcoming fields of interest, metal organic framworks (MOFs) are intensively studied.[1,2] As a preliminary stage in designing new MOF structures, simpler coordination polymers containing the often used paddle wheel structure were synthesized in order to
investigate conductivity properties. Because of its ability of being oxidized, [Rh2(ac)4] and its derivatives, as representatives of this class, were linked via pyrazine and other conjugated organic molecules.[3,4] These polymers were synthesized as powders and were dip coated onto gold surfaces. Afterwards they were characterized using inter alia XRD, XPS, TG-DSC and AFM. To gain knowledge about the conductivity of these materials and to clarify the underlying charge transport mechanism, temperature dependent current voltage spectroscopy was performed using conductive AFM. So far measurable currents even above room temperature were only observed for [Rh2(acam)4pyz]n coordination polymers. Here, we measured an increase of the conductivity with increasing temperature. As a result of these measurements the activation energy for the transport of charge carriers and the voltage barrier according to the Poole-Frenkel mechanism were obtained.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[1] J. Liu, C. Wöll, Chem. Soc. Rev. 2017, 46, 5730–5770.
[2] A. S. Münch, F. O. Mertens, Microporous Mesoporous Mater. 2018, 270, 180–188.
[3] M. Handa, Y. Muraki, S. Kawabata, T. Sugimori, I. Hiromitsu, M. Mikuriya, K. Kasuga, Mol. Cryst. Liq. Cryst. 2002, 379,
327–332.
[4] T. P. Zhu, M. Q. Ahsan, T. Malinski, K. M. Kadish, J. L. Bear, Inorg. Chem. 1984, 23, 2–3.

Figure 1: Height image of a
[Rh2(acam)4pyz]n pyramid (100 cycles).
The red arrow marks C-AFM measurements position. The distribution of pyramids can be found in the inset.

Figure 2: Temperature dependent C-AFM measurements on a [Rh2(acam)4pyz]n pyramid.
(Inset: Poole-Frenkel plot and determination of the resulting voltage barrier.)

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Thi Quynh Tran: "Deciphering the effect of matrix stiffness on cell mechanics"

University of Mons, Belgium

In the field of cell mechanics, hydrogels are popularly used to mimic in-vitro the cell microenvironment due to their tuneable tissue-like properties. Interestingly, physicochemical properties of the extracellular matrix (ECM) can couple with numerous cell processes, such as differentiation [1], replication, migration [2],[3], and apoptosis [4]. In this work, commercial hydrogels (from Matrigen), polydimethylsiloxane and hydroxy-polyacrylamide hydrogels (hydroxy-PAAm)[5] were used to study the impact of the hydrogel stiffness on endothelial cell mechanics. Firstly, the viscoelastic properties were estimated in physiological conditions by nano Dynamic Mechanical Analysis, based on single force curves, while the probe is indenting the surface with nano-Newton forces. Our findings show a linear stiffness gradient while the bis-acrylamide/acrylamide ratio increases. In addition, we show that the adhesion from PeakForce Quantitative NanoMechanics (PF QNM) is higher significantly than the value obtained in Force Volume (⁓0.2nN). Then we quantitatively mapped the nanomechanical properties of human umbilical vein endothelial cells (HUVECs) plated on polydimethylsiloxane. We found that the elastic modulus of the cell body is about 12-18 kPa which is higher than the cell lamellipodia (5-10 kPa) with Tan  about ⁓0.5 for cell body.

Figure 1: Schematic for tip–cell surface interaction; AFM images (loss modulus and storage moduli, and Tan ) of live human umbilical vein endothelial cells in liquid.


References
[1] A. P. Kourouklis, K. B. Kaylan, and G. H. Underhill, “Substrate stiffness and matrix composition coordinately control the differentiation of liver progenitor cells,” Biomaterials, 2016.
[2] Q. Luo, D. Kuang, B. Zhang, and G. Song, “Cell stiffness determined by atomic force microscopy and its correlation with cell motility,” Biochim. Biophys. Acta - Gen. Subj., vol.
1860, no. 9, pp. 1953–1960, 2016.
[3] W. J. Hadden et al., “Stem cell migration and mechanotransduction on linear stiffness gradient hydrogels,” Proc. Natl. Acad. Sci. U. S. A., vol. 114, no. 22, pp. 5647–5652, 2017.
[4] Y. H. Zhang, C. Q. Zhao, L. S. Jiang, and L. Y. Dai, “Substrate stiffness regulates apoptosis and the mRNA expression of extracellular matrix regulatory genes in the rat annular cells,” Matrix Biol., vol. 30, no. 2, pp. 135–144, 2011.
[5] T. Grevesse, M. Versaevel, and S. Gabriele, “Preparation of Hydroxy-PAAm hydrogels for decoupling the effects of mechanotransduction cues,” J. Vis. Exp., no. 90, pp. 1–8, 2014.

 

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Laia Pasquina-Lemonche: "The bigger picture by AFM: peptidoglycan structure of Gram-positive bacteria and its destruction by antibiotics"

University of Sheffield, United Kingdom

The primary structural component of the bacterial cell wall is peptidoglycan which is crucial for survival and division of the cells. Peptidoglycan (PG) is a heterogeneous macromolecule composed of glycan chains (sugars) and small peptides that unify the structure by crosslinking the glycan chains. PG is tens of nanometres thick in Gram-positive bacteria and acts as a constraint to interrupt turgor. This component of the cell is also one of the major targets by cell wall antibiotics such as Methicillin or Vancomycin. In this project, we applied several imaging modes of atomic force microscopy (AFM) to interrogate the morphology of this heterogeneous hydrogel. The bacteria of study were Staphylococcus aureus and Bacillus subtilis which are two Gram-positive species with distinct cell shape (sphere vs rod). High resolution tapping was used to image the external surface of live cells and PeakForce Tapping was used to study both the internal and external surface of purified PG. Then, quantitative image analysis methods were developed to obtain robust conclusions when comparing different samples. The results were that contrary to stablished theories, the PG is not a homogeneous impenetrable wall, it is a highly porous heterogeneous hydrogel [1].
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1 – Model made using real AFM images of different parts of the cell wall – resolution: ~ 1 nm

 

Then, once the architecture of PG from healthy cells was well characterised, the same techniques were applied to study the effect of different antibiotics (Methicillin and Vancomycin) to the PG morphology. We used Staphylococcus aureus wild type, together with different mutants to decipher the role of PG modification enzymes during cell death [2]. The results corroborate the model that for the cell to survive there must be an equilibrium between synthesis and hydrolysis of PG, this equilibrium is disrupted when antibiotics are applied, therefore leading to cell death. This brings us one step closer to obtain a complete bigger picture of how the bacterial cell wall evolves during the life and death cycle.

References:

[1] L. Pasquina-Lemonche, J. Burns, R.D. Turner, S. Kumar, R. Tank, N. Mullin, J. S. Wilson, B. Chakrabarti, P. A. Bullough, S. J. Foster, J. K. Hobbs, “The architecture of the Gram-positive bacterial cell wall”, Nature, 582, 294-297 (2020).

[2] Bartlomiej Salamaga, Lingyuan Kong, Laia Pasquina-Lemonche, Lucia Lafage, Milena von und zur Muhlen, Josie F. Gibson, Danyil Grybchuk, Amy Tooke, Viralkumar Panchal, Elizabeth J. Culp, Elizabeth Tatham, Mary E. O’Kane, Thomas E. Catley, Stephen A. Renshaw, Gerard D. Wright, Pavel Plevka, Per A. Bullough, Aidong Han, Jamie K. Hobbs, Simon J. Foster, “Demonstration of the role of cell wall homeostasis in Staphylococcus aureus growth and the action of bactericidal antibiotics”, PNAS, submitted (2021)

 

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Solène Lecot: "Modeling Single Molecule Force Spectroscopy - AFM mode by Steered Molecular Dynamics simulations: Effects of silane monolayers on protein adsorption and on analyte recognition"

Ecole Centrale de Lyon, France 

Protein adsorption on surfaces is used in biosensing tools as an immobilization mean to trap the analyte to be detected. However, adsorption can lead to conformational changes in the protein structure, resulting in a loss of bioactivity. Among surfaces, self-assembled monolayers of silane molecules are widely used to functionalize SiO2, as their surface charge and hydropathy can be tuned by using silane molecules with different head-group charges and alkyl chain lengths. The objective of this study is to decipher the impact of different silane monolayers on the adsorption of proteins and on their further interactions with targeted biomolecules, by Molecular Dynamic (MD) simulations and by Steered Molecular Dynamics (SMD) simulations, which mimic Atomic Force Microscopy (AFM) experiments.

 

Firstly, the model system “streptavidin-biotin” was investigated. Among all the silane monolayers studied, highly hydrophobic monolayers with short alkyl chains and with neutral head-groups would be the most adapted to allow Streptavidin adsorption while keeping its bioactivity towards Biotin [1]. Indeed, these monolayers lead to the lowest adsorption-induced conformational changes in Streptavidin. Moreover, the residues with high mobility are away from the Biotin binding pocket. Also, the Biotin-Streptavidin rupture force on this monolayer is not only similar to that obtained, from MD simulation, in the native state in water without surface, but also in agreement with that obtained from AFM experiments [2].

 

Then, the same methodology was applied to the “cellular receptor ACE2–Spike protein of the SARS-CoV-2” complex. The entry of the SARS-CoV-2 into the host cell involves the interaction between the cellular receptor ACE2 and the viral spike protein. Consequently, ACE2 could be a target with limited mutation escaping possibilities. However, because ACE2 has not evolved to recognize the spike protein, the ACE2–spike protein affinity needs to be improved for diagnosis use. Our results suggest that the adsorption of ACE2 on silane monolayers combining two types of silane molecules (positively charged silane molecules and highly hydrophobic neutral silane molecules) induces an increase in the rupture force of spike protein, through the formation of novel hydrogen bonds, indicating a significant reinforcement of the ACE2 – spike protein affinity.

 

References:

[1] S. Lecot, Y. Chevolot, M. Phaner-Goutorbe and C. Yeromonahos, J. Phys. Chem. B, 124 (2020), p.6786-6796.

[2] F. Rico, A. Russek, L. Gonzalez, H. Grubmüller and S. Scheuring, PNAS, 116 (2019), p.6594-6601.

 

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Gnanachandran Kajangi: "Mechanical and Microrheological properties of Bladder Cancer Cells: from Single Cells to 3D Multicellular Spheroids"

Institute of Nuclear Physics PAN, Poland

Cancer progression is associated with changes in the mechanical properties of cells. Atomic Force Microscopy (AFM) is a versatile tool used to study cell elastic and rheological properties. Here, we investigate biomechanics at different complexity levels: single cells, monolayers, and 3D multicellular spheroids. Three different cell lines were used: HCV29 (non-malignant cancer), HT1376 (grade III carcinoma), T24 (grade IV transitional cell carcinoma). Three parameters were compared: Young’s (compression), storage and loss (shear stress) moduli. Our results show that under compression, HCV29 is stiffer than HT1376 and T24. Thus, cancer cells are softer than non-malignant ones. HCV29 and T24 rigidity increases when cells are grown as monolayer. Similar relation is observed for cells undergoing shear stress. The elastic properties of HT1376 cells in monolayer are of the same order as for single HT1376 cells regardless of the type of applied deformation. The mechanical and rheological properties of bladder cancer cells are related to actin filament organisation as stress fibres are present in HCV29 and T24 cells, and not in HT1376 ones. All three cell lines form spheroids diversely and change biomechanics at the 3D level, but still, cancer cells were softer. Both mechanical (compression) and rheological (shear stress) properties may serve as a biophysical cancer marker.

 

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Assoc. Prof. Talgat Sharipov: "SPM of DNA with a homonucleotide sequence"

Bashkir State University, Russia

The physical properties of DNA molecules, both natural double-stranded and synthesized single-stranded, are currently being actively studied. Thanks to the invention of scanning tunneling (STM) and atomic force microscopes (AFM) it became possible to study various nanoobjects at the molecular and submolecular levels. Obviously, that DNA molecules, and in particular oligonucleotides, are no exception. Synthetic single-stranded DNA with a homonucleotide sequence, that is, consisting of nucleotides of the same type are of particular interest. Such structures assume a special nature of the electron density distribution and charge transfer, so the interest in them is consistently high, what is associated with the prospects of using these molecules in nanoelectronics.

 

Attempts to measure the electrical resistance of DNA give conflicting results [1-4]. The ambiguity of the results is influenced by the experimental conditions and the type of DNA molecules studied [5], namely length, nucleotide composition, different sequence of nucleotides in the DNA chain, the number of chains in the molecule. The study of the surface topography and immobilization of the DNA molecules by scanning probe microscopy methods is also important in terms of the development of DNA microarrays [6, 7].

 

We can measure the current-voltage curve of a biomolecule using STM. For this, the molecule is placed between two electrical contacts, one of which is a conducting probe of the microscope, and the other – a fragment of the substrate surface of an electrically conductive material.

We set the task of performing the series of experiments to study the conductivity of oligonucleotides depending on their nucleotide composition. In the report we will present the results of STM/STS studies of oligonucleotides consisting of repeated nucleotide sequences of only one type, for example, cytosine - d(C)n, where n is the number of such nucleotides.

 

First, by thermal evaporation of silver on a mica surface in a vacuum, we obtained a silver substrate. Next, the obtained substrate was coated with the studied molecules. Then we carried out STM study of the silver surface with immobilized oligonucleotide molecules by the constant tunneling current mode. In addition to obtaining a number of STM images and identifying oligonucleotides on them, the current-voltage curves of single molecules have been measured. In this case, the current-voltage curve is the dependence of the tunneling current on the applied voltage between the probe and the silver substrate. The current-voltage curves were measured several times at each point, and then the data were averaged. The differential electrical resistance of individual molecules of oligonucleotide d(C)12 and oligonucleotide d(A)12 was estimated.

 

References

[1]    H.W. Fink and C. Schonenberger. Nature 398(1999) 407.

[2]    D. Porath, A. Bezryadin, S. De Vries and C. Dekker. Nature London 403(2000)635.

[3]    T.I. Sharipov, R. R. Garafutdinov, R.Z. Bakhtizin. Bulletin of the Russian Academy of Sciences. Physics. 2020. Vol. 84. No 5. P. 675-678.

[4]    T. I. Sharipov, R. Z. Bakhtizin. University bulletin. Volga region. Physics and mathematics sciences. Astronomy. – 2019. – No 1 (Vol 49). – P. 115-122.

[5]    M. Iijima, T. Kato, S. Nakanishi, H. Watanabe, K. Kimura, K. Suzuki and Y. Maruyama. Chemistry Letters 34, 8(2005)1084.

[6]    T.I. Sharipov, R.Z. Bakhtizin. IOP Conf. Series: Materials Science and Engineering 195(2017)012002.

[7]    R.R. Garafutdinov, I.S. Shepelevich, A.V. Chemeris, R.F. Talipov. Vestnik Bashkirskogo universiteta T. 10. No 1(2005)49.

 

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Qiwei Hu: "Investigating Triboelectric Charging by a combination of AFM-based Force Spectroscopy and Kelvin Probe Force Microscopy"

University of Freiburg, Germany

The triboelectric effect has been known for thousands of years but the physical origins are still unclear. It describes a charge separation process when two materials are contacted or are in motion against each other. This effect is used in triboelectric nanogenerators (TENGs) that harvest energy by contacting pairs of tribo-functional materials. TENGs are used for energy autonomous devices. They can work as micro-scale power sources for small electronic sensor networks, macro-scale power sources for harvesting energy from ocean tides and waves (blue energy) and self-powered sensors in MEMS for instance [1, 2]. Here, we use a combination of two different AFM-based techniques study to the extent of charge separation after contacting various materials. Atomic Force Microscopy (AFM)-based force spectroscopy is used to contact the respective materials. Kelvin Probe Force Microscopy (KPFM) is performed to obtain the surface potentials before and after such contacting experiments. In addition, the adhesive interaction between two surfaces is quantified by the force-extension curves from contacting and correlated to the change of surface potentials. This work will open new perspectives for the characterization and understanding of the triboelectric effect. Furthermore, the presented techniques will enable us to test new triboelectric materials for future functional polymer-based material systems.


Reference
[1] Z. L. Wang, ACS Nano, vol. 7, No. 11, 9533-9557, 2013.
[2] Z. L. Wang, Faraday Discussion, vol. 176, 447-458, 2014.

 

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​​​Dr. Iuliana Stoica: "Advanced morphological and statistical analysis of laser induced micro/nano multiscale surface relief gratings on azo-polyimide films"

Iuliana Stoica1*, Ion Sava1, Jolanta Konieczkowska2, Ewa Schab-Balcerzak2

 

1 "Petru Poni" Institute of Macromolecular Chemistry, 700487 Iasi, Romania

2 Centre of Polymer and Carbon Materials Polish Academy of Sciences, 41-819 Zabrze, Poland

A series of micro/nano structured azo-polyimide films via irradiation with a pulsed laser, through a diffraction phase mask, using various incident fluencies and number of pulses are thoroughly investigated using Atomic Force Microscopy (AFM). The effect of the azochromophore type, the chemical structure of the polymer backbone and the irradiation conditions on the morphological aspect of the SRGs are investigated. The competing mechanisms that lead to the formation of progressively distinguished compact linear periodic three-dimensional grooves with ridges relatively flatten, exhibiting no supplementary organization at a low number of pulses or to hierarchical micro/nano multiscale surface relief gratings at a high number of pulses are explained. The interdependence of the statistical texture parameters with the irradiation conditions and chemical structure of the azo-polyimide is important in controlling the contact area of the patterned azo-polyimide surfaces at the interface with other materials for optoelectronic devices.

 

ACKNOWLEDGEMENT

This work was funded by the national fellowship program L’Oreal – Unesco “For Women in Science”.

 

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​​​Dr. Andreea Irina Barzic: "Mechanical alteration of the morphological features of a polyimide and their impact on interfacial compatibility"

Andreea Irina Barzic, Iuliana Stoica, Raluca Marinica Albu

 

“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania

Polyimides (PIs) are engineering plastics of great relevance in many technical applications, like solar cells, displays, interlayer dielectrics, encapsulants and so on. For such practical purposes, the PIs are interfaced with other materials, hence a close examination of their morphological and wettability characteristics is essential for attaining the desired interfacial compatibility. In this work, a semi-aliphatic polyimide film is subjected to a surface mechanical treatment. The induced changes on the morphological features are investigated by atomic force microscopy (AFM). The obtained data show that the pristine PI film displays anisotropic peak-to-valley height type of the surface. Upon applying the roughening treatment the PI film surface is transformed into an anisotropic one composed of microgrooves. Deeper processing of the registered AFM data enabled to obtain the amplitude distribution function, the shape parameters, surface functional indexes and functional volume parameters.The altered surface of the investigated sample reveals an anisotropic character of adhesion or spreading properties of various materials brought in contact with PI layer.

 

 

Acknowledgements: This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS/CCCDI – UEFISCDI, project number TE 83/1.09.2020 within PNCDI III (code PN-III-P1-1.1-TE-2019-1878).

 

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Arkadiusz Foks: "Study of nanostructures formed by the interaction of highly charged ions with gold nanolayers using atomic force microscopy"

Jan Kochanowski University, Poland

The method of surface modification by the impact of low-energy highly charged ions (HCI) can be used to change the topology of the surface, and thus has potential to develop materials with new and unique properties. [1]. This method can be used e.g. for creation of various surface nanostructures (pits, craters, hillocks) [2], for nano- pattering [3], and perforating of single-layer materials [4]). In this work, modifications of Au nanolayers caused by HCI xenon ions were studied. The nanolayers were prepared at Institute of Electron Technology (Warsaw, Poland) using VST TFDS- 462U deposition system. As a substrate Topsil (Warsaw, Poland) Si (110) polished prime wafers type N were used. The nanolayers were irradiated with Xe^q+ (q = 15 – 40) ions in the energy range hundreds of keV (nuclear stopping power regime) at a fluence of about 10^10 ions/cm^2 using low energy highly charged ions accelerator with the EBIS ion source installed at Institute of Physics, Jan Kochanowski University (Kielce, Poland) [5, 6]. The topographic modifications of the samples surface induced by Xe^q+ ions were investigated using atomic force microscopy (Faculty of Chemistry, UMCS, Lublin, Poland). Well pronounced modifications of the nanolayers surface, due to impact of the HCI ions, in the form of craters have been observed (Figure 1). The AFM measurements of the studied samples were performed using Multimode 8 (Bruker) AFM equipped with NanoScope software (Bruker-Veeco, USA). The AFM was operated in SCANASYST-HR fast scanning mode using SCANASYST-AIR-HR probe (Silicon Tip on Nitride Lever) (Bruker) with the cantilever of force constant k = 0.4 N/m. The lateral and vertical resolutions were 4 nm and 0.1 nm for the 1 μm x 1μm, and 2 nm and 0.1 nm for the 500 nm x 500 nm images. The obtained images were analyzed with Nanoscope Analysis ver. 1.40 software (Veeco, USA). The collected data made it possible to correlate the mean nanostructures size (diameters, depths, volumes) with different ion parameters. Statistical analysis of the formed structures was performed to determine such dependences as: the crater depth on the ions kinetic energy, the diam- eter of craters on the ions potential energy and the number of craters on the ions fluence.

 

References [1] J. V. Barth et al. 2005 Nature 437 671 [2] F. Aumayr et al. 2011 J. Phys.: Condens. Matter 23 393001 [3] J. Gierak 2014 Nanofabrication 1 35 [4] R.Kozubeketal.2019J.Phys.Chem.Lett.10(5) 904 [5] D. Bana ́s et al. 2015 Nucl. Instr. Meth. B 354 125 [6] I. Stabrawa et al. 2017 Nucl. Instr. Meth. B 408 235

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Krishnaveni Palanisamy: "Solid electrolyte interphases at Hard Carbon anode materials via Scanning Probe Microscopy Techniques"

Ulm University, Germany

Hard carbon (HC) is an efficient negative electrode materials for Na-ion batteries (SIB) [1,2]. Hard carbons can deliver high capacity since the random alignment of small-dimensional graphene layers provides significant porosity for Na-ion intercalation, whereas graphite cannot accommodate Na ions due to its larger size; the formation of intercalation compound with defect-free graphite is non-existent [3,4].  In comparison to Li-ion batteries where the solid-electrolyte interphase (SEI) is studied for decades, less information on SEI formation in dependence of the used electrolyte is known for HC.

With this contribution, we present studies on the physical and electrochemical properties of the formed SEI layer on HC electrodes, which were cycled in 1 M NaClO4 / propylene carbonate (PC) solvent with fluoroethylene carbonate (FEC) as possible additive. Scanning probe microscopy techniques such as scanning electrochemical microscopy (SECM) provide information on the electrochemical SEI layer properties [5,6], whereas AFM was used to  determine changes in morphology and surface roughness. The formation of the SEI was studied on the cycled HC electrode with and without FEC additives. The obtained results reveal a direct insight into the surface morphology and its structure-reactivity correlation, which provides understanding of the SEI formation on HC, which may in future guide the design and development of sustainable high-energy Na-ion batteries.

References:

  1. Y. Li, Y.-S. Hu, M.-M. Titirici, L. Chen, X. Huang, Adv. Energy Mater. 2016, 6, 1600659

  2. Z. Li, Z. Jian, X. Wang, I. A. Rodriguez-Perez, C. Bommier, X. Ji, Chem. Commun. 2017, 53, 2610.

  3. Y. Wen, K. He, Y. Zhu, F. Han, Y. Xu, I. Matsuda, Y. Ishii, J. Cumings, C. Wang, Nat. Commun. 2014, 5, 4033.

  4. Y.-E. Zhu, L. Yang, X. Zhou, F. Li, J. Wei, Z. Zhou, J. Mater. Chem. A 2017, 5, 9528.

  5. S.C.S. Lai, J.V. Macpherson, P.R. Unwin, MRS Bull. 2012, 37, 668.

  6. T. S. Watkins, D. Sarbapalli, M. J. Counihan, A. S. Danis, J. Zhang, L. Zhang, K. R. Zavadil, J. R.-Lopez, J. Mater. Chem. A, 2020, 8, 15734.

 

 

This work contributes to the research performed at CELEST (Center for Electrochemical Energy Storage Ulm-Karlsruhe), and was funded by the German Research Foundation (DFG) under Project ID 390874152 (POLiS Cluster of Excellence)

 

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Sy Hieu Pham: "Nanoscale current spreading analysis of electrodeposited silver nanowires network by using the conductive-atomic force microscopy"

Artois University, France

Silver nanowire networks (AgNW) have demonstrated high optical transparency, low sheet resistance and are promised to be a next-generation transparent conductive electrode (TCE). The electrical properties of the AgNW network strongly depend on the contact resistance and the number of junctions. In this work, we have used an electroplating method of Ag on AgNW to improve the contact resistance of the AgNW network. In addition, electrodeposition of Ag on AgNW TCEs can provide higher conductivity than spin-coated AgNW TCEs at the same transparency, due to increased diameter of the nanowire by the epitaxial growth. The optimized experimental conditions have revealed a sheet resistance as low as 12 Ohm/sq associated to a high transmittance larger than 88% measured at λ = 550 nm on flexible PET substrate. In this study, the morphological properties as well as the electrical behavior of the AgNWs network was thoroughly investigated on the nanoscale by means of the conductive mode of the Atomic Force Microscopy (c-AFM). The recording of both current mapping and local I(V) characteristics have particularly demonstrated a high-performance percolating conductive network. The obtained results allow us to propose a methodology to elaborate new transparent electrodes suitable for flexible displays, organic light-emitting diodes, or thin-film solar cells.

 

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Claudiu Hapenciuc: "Quantitative evaluation of thermal conductivity measurement error in Scanning Thermal Microscopy induced by an asymmetry in the probe-sample contact point"

National Institute for Lasers Plasma and Radiation Physics, Romania

Scanning Thermal Microscopy is a widely recognized technique for thermal conductivity measurements of bulk and nanostructured materials. Wollaston probes are presently used in contact or noncontact mode for thermal conductivity measurement. They can be reliably fabricated in the laboratory and offer an appropriate spatial resolution from few microns to hundreds of nanometers. A study is reported herewith on the errors that can affect the average temperature rise and related probe thermal resistance with direct impact on thermal conductivity evaluation, as a consequence of a contact point asymmetry. The new theoretical models proposed and its results can be used or adapted to any kind and size of hot probe. The study is based on the fin heat conduction equation applied on three regions of the probe: left, middle and right, in respect to the contact point. The thermal conductivity calculation for a thin film on substrate is simulated and the errors that raise from using an asymmetric contact point are inferred for the three values of the asymmetry. They are next compared to simulations obtained using a simplified model of heat transfer inside the probe and from probe to sample. The accuracy of the two models is comparatively analyzed in order to select the optimum one. This analysis can serve as an eventual evaluation criterion of experimental accuracy of the method and improvement possibilities.

 

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Assoc. Prof. István Csarnovics: "Plasmonic nanostructures for photonic applications"

University of Debrecen, Hungary

In this work, the performance of plasmonic nanoparticles was investigated for photonic applications. It is widely used for surface plasmon resonance experiments, not in the last place because of the manifestation of optical resonances in the visible spectral region. The localized surface plasmon resonance (LSPR) is rather easily observed in nanometer-sized metallic structures and widely used for measurements, sensing, semiconductor devices, and even in optical data storage.

Firstly, gold nanoparticles on silica glass substrate satisfy the conditions for surface plasmon resonance in the green-red spectral range, where the chalcogenide glasses have the highest sensitivity. The gold nanostructures influence and enhance the optical, structural, and volume changes and promote the exciton generation in gold nanoparticles/chalcogenide layer structure. The experimental results support the importance of localized electric fields in the photo-induced transformation of chalcogenide glasses as well as suggest new approaches to improve the performance of these optical recording media. Results may be utilized for direct, micrometer- or submicron size geometrical and optical pattern formation in the. Besides that, gold nanoparticles could be added to organic light-sensitive material. The acrylate-based materials are frequently used for the optical, holographic recording of optoelectronic elements due to photo-stimulated structural transformations. The holographic recording process and photo-polymerization the effect could be enhanced by the localized plasmon field of the created gold nanostructures.

Atomic force microscope measurements were performed on the 1D and 2D periodic structures based on inorganic chalcogenide layer structures and organic polymer nanocomposites. It was shown that adding gold nanoparticles to these samples, enhances the amplitude, height, and the diffraction the efficiency of these structures, so the process of the light-induced volume change.

Acknowledgment: This work was supported by GINOP- 2.3.2-15-2016-00041 project, which is co-financed by the European Union and European Social Fund. Istvan Csarnovics is grateful for the support of the János Bolyai Research Scholarship of the Hungarian Academy of Sciences (BO/348/20) and the support through the New National Excellence Program of the Ministry of Human Capacities (ÚNKP-21-5).