Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Nanotribology, Surface Interactions and Characterization: An AFM Study
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

When two surfaces achieve contact, then contact phenomena such as adhesion, friction and wear can occur, which are of great interest in many disciplines, including physics, physical chemistry, material chemistry, and life and health sciences. These phenomena are largely determined by the nature and magnitude of the surface forces such as van der Waals, capillary and hydration forces. Moreover these forces are length-dependent, and therefore when the system scales down, their contribution scales up, dominating the interaction between the surfaces.

A goal of my PhD work was to investigate fundamental contact phenomena in terms of the surface forces that regulate their properties. The primary tool applied in this PhD thesis work has been the atomic force microscopy (AFM), which (with all of its sub-techniques) offers the possibility to study such forces with high resolution virtually between all types of materials and intervening media. Therefore, in this work it was possible to study the long ranged interactions presented in air between different industrially relevant materials and how these interactions are shielded when the systems are immersed in an ionic liquid.

Also investigated was the influence of microstructure on the tribological properties of metal alloys, where their good tribological properties were related with the vanadium and nitrogen contents for a FeCrVN tool alloy and with the chromium content for a biomedical CoCrMo alloy. Moreover, the effect of the intervening media can significantly affect the surface properties, and when the biomedical CoCrMo alloy was immersed in phosphate buffer saline solution (PBS), repulsive hydration forces decreased the friction coefficient and contact adhesion. On the other hand, with the immersion of the FeCrVN tool alloy in the NaCl solution, small particles displaying low adhesion were generated in specific regions on the surface with low chromium content. These particles are assumed to be related to a prepitting corrosion event in the tool alloy.

The mechanical properties of stratum corneum (SC), which is the outermost layer of the skin, were also studied in this work. The SC presents a highly elastic, but stiff surface where the mechanical properties depend on the nanoscale. A novel probe has been designed with a single hair fibre in order to  understand how the skin deforms locally in response to the interaction with such a fibre probe. This study revealed that is mostly the lateral scale of the deformation which determines the mechanical properties of the SC.

Finally, important achievements in this work are the developments of two new techniques - tribological property mapping and the Hybrid method for torsional spring constant evaluation. Tribological property mapping is an AFM technique that provides friction coefficient and contact adhesion maps with information attributed to the surface microstructure. The Hybrid method is an approach that was originally required to obtain the torsional spring constants for rigid beam shaped cantilevers, which could not be previously determined from their power torsional thermal spectra (conventional method). However, the applicability is shown to be general and this simple method can be used to obtain torsional spring constants for any type of beam shape cantilever.

 

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. , xviii, 78 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2014:13
National Category
Nano Technology
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-145727ISBN: 978-91-7595-102-7 (print)OAI: oai:DiVA.org:kth-145727DiVA: diva2:720102
Public defence
2014-06-13, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20140603

Available from: 2014-06-03 Created: 2014-05-28 Last updated: 2014-06-30Bibliographically approved
List of papers
1. Ionic Liquid Nanotribology: Stiction Suppression and Surface Induced Shear Thinning
Open this publication in new window or tab >>Ionic Liquid Nanotribology: Stiction Suppression and Surface Induced Shear Thinning
2012 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 28, no 26, 9967-9976 p.Article in journal (Refereed) Published
Abstract [en]

The friction and adhesion between pairs of materials (silica, alumina, and polytetrafluoroethylene) have been studied and interpreted in terms of the long-ranged interactions present. In ambient laboratory air, the interactions are dominated by van der Waals attraction and strong adhesion leading to significant frictional forces. In the presence of the ionic liquid (IL) ethylammonium nitrate (EAN) the van der Waals interaction is suppressed and the attractive/adhesive interactions which lead to "stiction" are removed, resulting in an at least a 10-fold reduction in the friction force at large applied loads. The friction coefficient for each system was determined; coefficients obtained in air were significantly larger than those obtained in the presence of EAN (which ranged between 0.1 and 0.25), and variation in the friction coefficients between systems was correlated with changes in surface roughness. As the viscosity of ILs can be relatively high, which has implications for the lubricating properties, the hydrodynamic forces between the surfaces have therefore also been studied. The linear increase in repulsive force with speed, expected from hydrodynamic interactions, is clearly observed, and these forces further inhibit the potential for stiction. Remarkably, the viscosity extracted from the data is dramatically reduced compared to the bulk value, indicative of a surface ordering effect which significantly reduces viscous losses.

Keyword
Adhesion, Alumina, Hydrodynamics, Ionic liquids, Silica, Surface roughness, Van der Waals forces
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-99422 (URN)10.1021/la3010807 (DOI)000305869500009 ()2-s2.0-84863454555 (Scopus ID)
Funder
Swedish Research Council
Note
QC 20120731Available from: 2012-07-31 Created: 2012-07-30 Last updated: 2017-12-07Bibliographically approved
2. Note: Determination of torsional spring constant of atomic force microscopy cantilevers: Combining normal spring constant and classical beam theory
Open this publication in new window or tab >>Note: Determination of torsional spring constant of atomic force microscopy cantilevers: Combining normal spring constant and classical beam theory
2013 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 84, no 9, 096102-096102-3 p.Article in journal (Refereed) Published
Abstract [en]

A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power spectrum is difficult to obtain due to the high resonance frequency and low signal/noise ratio. The applicability is shown to be general and this simple approach can thus be used to obtain torsional constants for any beam shaped cantilever.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2013
Keyword
AFM cantilevers, Atomic force microscopy cantilevers, Classical beam theory, High resonance frequency, Signal/noise ratio, Spring constants, Torsional constant, Torsional springs
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-133654 (URN)10.1063/1.4820345 (DOI)000325402000069 ()2-s2.0-84885112358 (Scopus ID)
Funder
Swedish Foundation for Strategic Research Swedish Research Council
Note

QC 20131111. Correction in: Review of Scientific Instruments vol. 85, issue 7, DOI: 10.1063/1.4890335, WoS: 000341176600076, Scopus: 2-s2.0-84904717182

Available from: 2013-11-11 Created: 2013-11-08 Last updated: 2017-12-06Bibliographically approved
3. Tribological Properties Mapping: Local Variation in Friction Coefficient and Adhesion
Open this publication in new window or tab >>Tribological Properties Mapping: Local Variation in Friction Coefficient and Adhesion
2013 (English)In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 50, no 3, 387-395 p.Article in journal (Refereed) Published
Abstract [en]

Tribological properties mapping is a new technique that extracts friction coefficient and adhesion maps obtained from lateral atomic force microscope (LAFM) images. By imaging the surface systematically as a function of load, a series of images can be tiled, and pixelwise fitted to a modified Amontons' Law to obtain friction coefficient and adhesion maps. This removes the ambiguity of friction contrast in LAFM imaging which can be a function of the load used for imaging. In ambient laboratory, air and tetradecane, a sample of Vancron(A (R))40, commercial powder metallurgical tool alloy containing nitrogen, have been scanned using a standard silicon cantilever in order to obtain tribological data. The tribological properties mapping provides unique information regarding the heterogeneous alloy microstructure as well as shedding light on the tribological behavior of the alloy.

Keyword
Friction, AFM, Atomic force microscope, LFM, Lateral atomic force microscope, Nanotribology, Friction coefficient mapping, Adhesion, Tool alloy, Microstructure
National Category
Tribology
Identifiers
urn:nbn:se:kth:diva-124457 (URN)10.1007/s11249-013-0136-8 (DOI)000319161700009 ()2-s2.0-84878246729 (Scopus ID)
Funder
Swedish Foundation for Strategic Research Swedish Research Council
Note

QC 20130709

Available from: 2013-07-09 Created: 2013-07-05 Last updated: 2017-12-06Bibliographically approved
4. Nanotribology and Microstructure of a CoCrMo Alloy: A TribologicalProperties Mapping Study
Open this publication in new window or tab >>Nanotribology and Microstructure of a CoCrMo Alloy: A TribologicalProperties Mapping Study
(English)Manuscript (preprint) (Other academic)
National Category
Tribology
Identifiers
urn:nbn:se:kth:diva-145901 (URN)
Note

QS 2014

Available from: 2014-06-03 Created: 2014-06-03 Last updated: 2014-06-03Bibliographically approved
5. Role of Microstructure on Pitting  Corrosion Initiation of an Experimental Tool Alloy: A Peak Force QNM Atomic Force Micrscopy Study
Open this publication in new window or tab >>Role of Microstructure on Pitting  Corrosion Initiation of an Experimental Tool Alloy: A Peak Force QNM Atomic Force Micrscopy Study
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Tribology
Identifiers
urn:nbn:se:kth:diva-145902 (URN)
Note

QS 2014

Available from: 2014-06-03 Created: 2014-06-03 Last updated: 2014-06-03Bibliographically approved
6. Nanomechanical Properties of Human Skin Studies by AFM and a Novel Hair Indenter
Open this publication in new window or tab >>Nanomechanical Properties of Human Skin Studies by AFM and a Novel Hair Indenter
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Tribology
Identifiers
urn:nbn:se:kth:diva-145903 (URN)
Note

QS 2014

Available from: 2014-06-03 Created: 2014-06-03 Last updated: 2014-06-03Bibliographically approved

Open Access in DiVA

Thesis(5324 kB)547 downloads
File information
File name FULLTEXT01.pdfFile size 5324 kBChecksum SHA-512
b934c7c1f16e725734a2648c8fb98b672cef4fc2648c9e1bae51ab300dae70aab323aff6a919173e2ff461f3fa0c1b2e52740d1d4ade5feaef7a9c5f20c9a173
Type fulltextMimetype application/pdf
errata(41 kB)11 downloads
File information
File name ERRATA01.pdfFile size 41 kBChecksum SHA-512
02637a01c97e51e27803090b37e93dc18f7860fd993fb7009998a9e7424a8b72a76752672296093d4859a316f6ef1efdb0a215d9f3fade38ba0139a17353a51c
Type errataMimetype application/pdf

Search in DiVA

By author/editor
Álvarez-Asencio, Rubén
By organisation
Surface and Corrosion Science
Nano Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 547 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 518 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf