Tag: Arrow-UHF

Real-time tracking of ionic nano-domains under shear flow

The behaviour of ions at solid–liquid interfaces underpins countless phenomena, from the conduction of nervous impulses to charge transfer in solar cells. In most cases, ions do not operate as isolated entities, but in conjunction with neighbouring ions and the surrounding solution. In aqueous solutions, recent studies suggest the existence of group dynamics through water-mediated clusters but results allowing direct tracking of ionic domains with atomic precision are scarce. *

Atomic force microscopy (AFM) can image single ions adsorbed at various solid–liquid interfaces. One of the main advantages of the technique is its ability to probe individual ions in-situ but with local contextual information about the interface over tens of nanometres at the point of measurement.*

High-speed atomic force microscopy (HS-AFM) operates similarly to standard AFM but with enhanced temporal resolution and can capture images at video rate, making it possible to track many molecular processes in real-time.*

In the article “Real-time tracking of ionic nano-domains under shear flow” Clodomiro Cafolla and Kislon Voïtchovsky use high-speed atomic force microscopy to track the evolution of Rb+, K+, Na+ and Ca2+ nano-domains containing 20 to 120 ions adsorbed at the surface of mica in aqueous solution. The interface is exposed to a shear flow able to influence the lateral motion of single ions and clusters. *

They report the achievement of single-ion spatial resolution with ~ 2 s temporal resolution.*

During the measurements, the AFM cantilever and the sample were fully immersed in the aqueous ionic solution of interest. The AFM probes used were NanoWorld Arrow-UHF ultra-high frequency AFM cantilevers. *

The results presented in the article provide some quantitative insights into the relationship between single ion properties and group dynamics at the solid–liquid interface in the presence of a microscale shear flow, with potential technological applications from manufacturing biomedical devices to enhancing the performance of aqueous ion-batteries.*

Figure 1 from “Real-time tracking of ionic nano-domains under shear flow” by Clodomiro Cafolla and Kislon Voïtchovsky: Example of time evolution for adsorbed Rb+ ions at the mica-water interface in the presence of a shear flow. (a) A time-lapse sequence shows consecutive high-resolution HS-AFM topographical images of Rb+ ions at the interface between mica and a 5 mM RbCl aqueous solution. Rb+ ions appear as bright orange-yellow protrusions standing taller than the mica surface (purple-black). Periodic rows and larger domains are clearly visible as well as singly adsorbed rubidium ions. (b) Representative image analysis highlighting Rb+ ions as orange markers (obtained by thresholding) and the idealised underlying lattice derived by inverse Fourier transform of the filtered power spectrum in each image of (a) (see ESI Section 3 for details on the procedure). (c) The algorithm automatically associates neighbouring ions (within distances < 0.52 nm) to the same cluster. Domains smaller than 5 ions are discarded here. The different clusters derived in each image are highlighted using different colours, keeping for each cluster the same colour over time. The cyan-coloured cluster offers a good example of temporal evolution. The scale bars in (a–c) represent 3 nm and the z-scale in (a) corresponds to 0.8 nm. NanoWorld Arrow-UHF ultra-high speed AFM probes were used for the high-speed atomic force microscopy (HS-AFM).
Figure 1 from “Real-time tracking of ionic nano-domains under shear flow” by Clodomiro Cafolla and Kislon Voïtchovsky:
Example of time evolution for adsorbed Rb+ ions at the mica-water interface in the presence of a shear flow. (a) A time-lapse sequence shows consecutive high-resolution HS-AFM topographical images of Rb+ ions at the interface between mica and a 5 mM RbCl aqueous solution. Rb+ ions appear as bright orange-yellow protrusions standing taller than the mica surface (purple-black). Periodic rows and larger domains are clearly visible as well as singly adsorbed rubidium ions. (b) Representative image analysis highlighting Rb+ ions as orange markers (obtained by thresholding) and the idealised underlying lattice derived by inverse Fourier transform of the filtered power spectrum in each image of (a) (see ESI Section 3 for details on the procedure). (c) The algorithm automatically associates neighbouring ions (within distances < 0.52 nm) to the same cluster. Domains smaller than 5 ions are discarded here. The different clusters derived in each image are highlighted using different colours, keeping for each cluster the same colour over time. The cyan-coloured cluster offers a good example of temporal evolution. The scale bars in (a–c) represent 3 nm and the z-scale in (a) corresponds to 0.8 nm.

*Clodomiro Cafolla and Kislon Voïtchovsky
Real-time tracking of ionic nano-domains under shear flow
Nature Scientific Reports volume 11, Article number: 19540 (2021)
DOI: https://doi.org/10.1038/s41598-021-98137-y

Please follow this external link to read the full article: https://rdcu.be/cPRBu

Open Access The article “Real-time tracking of ionic nano-domains under shear flow” by Clodomiro Cafolla and Kislon Voïtchovsky is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Optimized positioning through maximized tip visibility – Arrow AFM probes screencast passes 500 views mark

The screencast about NanoWorld Arrow Silicon AFM probes held byNanoWorld AG CEO Manfred Detterbeck has just passed the 500 views mark. Congratulations Manfred!

NanoWorld Arrow™ AFM probes are designed for easy AFM tip positioning and high resolution AFM imaging and are very popular with AFM users due to the highly symetric scans that are possible with these AFM probes because of their special tip shape. They fit to all well-known commercial SPMs (Scanning Probe Microscopes) and AFMs (Atomic Force Microscopes). The Arrow AFM probe consists of an AFM probe support chip with an AFM cantilever which has a tetrahedral AFM tip at its triangular free end.

The Arrow AFM probe is entirely made of monolithic, highly doped silicon.

The unique Arrow™ shape of the AFM cantilever with the AFM tip always placed at the very end of the AFM cantilever allows easy positioning of the AFM tip on the area of interest.
The Arrow AFM probes are available for non-contact mode, contact mode and force modulation mode imaging and are also available with a conductive platinum iridum coating. Furthermore the Arrow™ AFM probe series also includes a range of tipless AFM cantilevers and AFM cantilever arrays as well as dedicated ultra-high frequency Arrow AFM probes for high speed AFM.

To find out more about the different variations please have a look at:

https://www.nanoworld.com/arrow-afm-tips

You can also find various application examples for the Arrow AFM probes in the NanoWorld blog. For a selection of these articles just click on the “Arrow AFM probes” tag on the bottom of this blog entry.

 

 

Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics

When they are in put in contact with carbonate minerals dangerous environmental pollutants such as Pb2+ and Cd2+ are taken up by the solid phase assemblage and can be removed from aqueous solutions.*

As carbonates can be found almost everywhere and are easily exploitable this makes them interesting materials for environmental remediation.*

However, magnesite ( MGS ) is well-known for the slow dissolution and growth kinetics at room temperature conditions in the so-called dolomite problem.*

In their article “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” Fulvio Di Lorenzo, Tobias Arnold and Sergey V. Churakov use in situ atomic force microscopy (AFM) to investigate the growth of {10.4} magnesite surfaces in the absence and in the presence of Pb2+ as well as the effect of solution ageing.*

In their study the authors attempt to answer the question if and under which circumstances magnesium carbonate could be used in removing Pb from wastewater.*

The experimental results presented in above mentioned article have the object to discuss and evaluate the theoretical possibilities and the practical limitations that must be taken into account for the development of environmental remediation technologies based on magnesite.*

The experiments conducted in this study by  Fulvio Di Lorenzo et al. demonstrate that, although the thermodynamic conditions are encouraging, the transformation reaction between magnesite and cerrusite makes it improbably that it will play a crucial role in the development of remediation processes for PbII pollution.*

The authors of the study conclude that, although the thermodynamic conditions are encouraging, an environmental remediation process based on MGS as the substrate for a solvent-mediated transformation reaction is unlikely to play a crucial part in industrial applications due to the slow kinetics of MGS dissolution. However, the sluggish kinetics of MGS precipitation is favourable for Pb entrapment by the precipitation of carbonate from Mg2+ and Pb2+-bearing solutions, leading to a strong PbII enrichment in the solid phase even in far-from-equilibirum conditions.*

The in situ flow-through Atomic Force Microscopy was performed using Arrow-UHFAuD AFM probes in tapping mode.

Figure 8 from “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” by Fulvio Di Lorenzo et al: In situ observation of {10.4} surfaces of MGS in contact with acidic solution, pH 4 (HNO3). The images were acquired in tapping mode. The first row corresponds to height channels, while the second row reports the respective amplitude channels. (A) The dissolution at 25 °C is sluggish and it is not possible to detect any dissolution feature. (B) In the same conditions but at higher temperature (60 °C), dissolution features are observed on the {10.4} surfaces of MGS, despite the retrograde solubility. Yellow and blue lines of constant size are used to highlight the evolution of etch pits and step edges, respectively. This evidence demonstrates that the existence of kinetic barriers controls the dissolution of MGS at room temperature conditions. NanoWorld Arrow-UHFAuD AFM probes were used.
Figure 8 from “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” by Fulvio Di Lorenzo et al:
 In situ observation of {10.4} surfaces of MGS in contact with acidic solution, pH 4 (HNO3). The images were acquired in tapping mode. The first row corresponds to height channels, while the second row reports the respective amplitude channels. (A) The dissolution at 25 °C is sluggish and it is not possible to detect any dissolution feature. (B) In the same conditions but at higher temperature (60 °C), dissolution features are observed on the {10.4} surfaces of MGS, despite the retrograde solubility. Yellow and blue lines of constant size are used to highlight the evolution of etch pits and step edges, respectively. This evidence demonstrates that the existence of kinetic barriers controls the dissolution of MGS at room temperature conditions.

*Fulvio Di Lorenzo, Tobias Arnold, and Sergey V. Churakov
Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics
Minerals 2021, 11(4), 415
DOI: https://doi.org/10.3390/min11040415

Please follow this external link to read the full article: https://www.mdpi.com/2075-163X/11/4/415

Open Access : The article “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” by Fulvio Di Lorenzo, Tobias Arnold, and Sergey V. Churakov is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.