scholarly journals Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

2008 ◽  
Vol 1 (1) ◽  
pp. 1-8 ◽  
Author(s):  
G. Helas ◽  
M. O. Andreae

Abstract. We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

2008 ◽  
Vol 1 (1) ◽  
pp. 1-19
Author(s):  
G. Helas ◽  
M. O. Andreae

Abstract. We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.


Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 489
Author(s):  
Kohei Ono ◽  
Yuki Mizushima ◽  
Masaki Furuya ◽  
Ryota Kunihisa ◽  
Nozomu Tsuchiya ◽  
...  

A new method, namely, force–distance curve mapping, was developed to directly measure the adhesion force of individual aerosol particles by atomic force microscopy. The proposed method collects adhesion force from multiple points on a single particle. It also takes into account the spatial distribution of the adhesion force affected by topography (e.g., the variation in the tip angle relative to the surface, as well as the force imposed upon contact), thereby enabling the direct and quantitative measurement of the adhesion force representing each particle. The topographic effect was first evaluated by measuring Polystyrene latex (PSL) standard particles, and the optimized method was then applied on atmospherically relevant model dust particles (quartz, ATD, and CJ-1) and inorganic particles (ammonium sulfate and artificial sea salt) to inter-compare the adhesion forces among different aerosol types. The method was further applied on the actual ambient aerosol particles collected on the western coast of Japan, when the region was under the influence of Asian dust plume. The ambient particles were classified into sea salt (SS), silicate dust, and Ca-rich dust particles based on individual particle analysis (micro-Raman or Scanning Electron Microscope/Energy Dispersive X-ray Spectroscopy (SEM-EDX)). Comparable adhesion forces were obtained from the model and ambient particles for both SS and silicate dust. Although dust particles tended to show smaller adhesion forces, the adhesion force of Ca-rich dust particles was larger than the majority of silicate dust particles and was comparable with the inorganic salt particles. These results highlight that the original chemical composition, as well as the aging process in the atmosphere, can create significant variation in the adhesion force among individual particles. This study demonstrates that force–distance curve mapping can be used as a new tool to quantitatively characterize the physical properties of aerosol particles on an individual basis.


2002 ◽  
Vol 54 (1-2) ◽  
pp. 79-88 ◽  
Author(s):  
Seyda Dumrul ◽  
Stephane Bazzana ◽  
Juliusz Warzywoda ◽  
Ronald R Biederman ◽  
Albert Sacco

The Analyst ◽  
2018 ◽  
Vol 143 (12) ◽  
pp. 2765-2774 ◽  
Author(s):  
Victor W. Or ◽  
Armando D. Estillore ◽  
Alexei V. Tivanski ◽  
Vicki H. Grassian

AFM-PTIR is utilized to analyze atmospherically relevant multicomponent substrate deposited aerosol particles.


2016 ◽  
Vol 16 (15) ◽  
pp. 9761-9769 ◽  
Author(s):  
Andrew D. Hritz ◽  
Timothy M. Raymond ◽  
Dabrina D. Dutcher

Abstract. Accurate estimates of particle surface tension are required for models concerning atmospheric aerosol nucleation and activation. However, it is difficult to collect the volumes of atmospheric aerosol required by typical instruments that measure surface tension, such as goniometers or Wilhelmy plates. In this work, a method that measures, ex situ, the surface tension of collected liquid nanoparticles using atomic force microscopy is presented. A film of particles is collected via impaction and is probed using nanoneedle tips with the atomic force microscope. This micro-Wilhelmy method allows for direct measurements of the surface tension of small amounts of sample. This method was verified using liquids, whose surface tensions were known. Particles of ozone oxidized α-pinene, a well-characterized system, were then produced, collected, and analyzed using this method to demonstrate its applicability for liquid aerosol samples. It was determined that oxidized α-pinene particles formed in dry conditions have a surface tension similar to that of pure α-pinene, and oxidized α-pinene particles formed in more humid conditions have a surface tension that is significantly higher.


2009 ◽  
Vol 415 ◽  
pp. 9-12 ◽  
Author(s):  
Diana Portan ◽  
D. Ionita ◽  
Ioana Demetrescu

In this paper the elaboration and characterization of TiO2 nanotubes as a function of anodizing conditions are studied taking into consideration electrolyte composition and voltage. The obtained results show that the nanotubes dimensions and surface features depend on elaboration conditions. The technique of surface characteristics investigation (2D and 3 D images) was atomic force microscopy which permitted roughness and porosity evaluation.


2006 ◽  
Vol 21 (3) ◽  
pp. 547-551 ◽  
Author(s):  
Rosalía Poyato ◽  
Bryan D. Huey ◽  
Nitin P. Padture

Piezoresponse atomic-force microscopy (PFM) has been used to characterize the local piezoelectric properties of a novel, nanotube-patterned (“honeycomb”) thin film of BaTiO3 on Ti substrate synthesized hydrothermally at 200 °C. PFM amplitude and phase images, prior to the application of any direct current (dc) field, show ring-shaped piezoelectric regions that correspond to the nanostructure of this film. These results show clearly that the as-synthesized nanotube-patterned BaTiO3 thin film is piezoelectric, with a net spontaneous polarization perpendicular to the film–substrate interface. In addition, polarization switching and hysteresis were observed as a function of applied dc field, confirming that this novel fabrication procedure results in unique configurations of BaTiO3 film that are also ferroelectric.


1997 ◽  
Vol 358 (1-2) ◽  
pp. 268-273 ◽  
Author(s):  
G. Köllensperger ◽  
G. Friedbacher ◽  
M. Grasserbauer ◽  
L. Dorffner

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