Adhesion Forces for Mica and Silicon Oxide Surfaces Studied by Atomic Force Spectroscopy (AFS) (original) (raw)
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Surface adhesion and its dependence on surface roughness and humidity measured with a flat AFM tip
Applied Surface Science, 2012
The adhesion force between a surface and the tip of an atomic force microscope cantilever has been determined by recording force-distance curves with an atomic force microscope. Flat tips with a diameter of 2 m were used to mimic the adhesion between two parallel surfaces. In such a configuration, the location for the formation and breaking of the capillary water neck is a stochastic by nature, significantly different from that of a spherical tip. The adhesion force is measured as a function of relative humidity for smooth and chemically etched Si(1 0 0) surfaces. The roughness of the etched substrate reduces the adhesion by more than an order of magnitude, depending on the exact value of the relative humidity. The adhesion force increases with increasing humidity until a relative humidity of about 70%. Beyond a relative humidity of 70% a decrease of the adhesion force is observed. We anticipate that the latter is due to a decrease of the cross section of the water neck at the snap off point with increasing relative humidity.
Surface adhesion and its dependence on surface roughness and humidity measured with a flat tip
Applied Surface Science, 2012
The adhesion force between a surface and the tip of an atomic force microscope cantilever has been determined by recording force-distance curves with an atomic force microscope. Flat tips with a diameter of 2 m were used to mimic the adhesion between two parallel surfaces. In such a configuration, the location for the formation and breaking of the capillary water neck is a stochastic by nature, significantly different from that of a spherical tip. The adhesion force is measured as a function of relative humidity for smooth and chemically etched Si(1 0 0) surfaces. The roughness of the etched substrate reduces the adhesion by more than an order of magnitude, depending on the exact value of the relative humidity. The adhesion force increases with increasing humidity until a relative humidity of about 70%. Beyond a relative humidity of 70% a decrease of the adhesion force is observed. We anticipate that the latter is due to a decrease of the cross section of the water neck at the snap off point with increasing relative humidity.
Determination of the Adhesion Properties of Mica via Atomic Force Spectroscopy
International Journal of Modern Physics: Conference Series, 2012
This paper addresses the Adhesion of mica surface employing Atomic Force Microscope (AFM) as a surface force apparatus. AFM is commonly used for atomic and nano-scale surface measurements. Based on the relations between cantilever responses and tip–sample interaction, methods for quantitative evaluation of a sample's mechanical parameters are described and issues concerning the use of AFM are discussed. The measurement of the Force-Distance curve was performed implementing Atomic Force Spectroscopy (AFS). During these measurements, the static deflection of the cantilever is monitored as a function of piezoelectric element displacement. The recorded plot is then used to quantitatively measure the mechanical properties like adhesion and elastic modulus. Forces were measured by multiplying the distance by force constant of the cantilever thorough Hook's law. It was necessary to calibrate the force constant of the cantilever to perform a precise force measurement. Force-Distance...
Application of atomic force spectroscopy (AFS) to studies of adhesion phenomena: a review
Journal of adhesion science and …, 2005
This review article describes the fundamental principles of atomic force spectroscopy (AFS) and how this technique became a useful tool to investigate adhesion forces. AFS is a technique derived from atomic force microscopy (AFM) and can determine, at every location of the sample surface, the dependence of the interaction on the probe-sample distance. AFS provides valuable information, at the nano-scale, such as, for example: (i) how the magnitude of the adhesion force depends on long-and short-range interactions and (ii) the tip-sample contact area. An overview about the theory and experiments with local force spectroscopy, force imaging spectroscopy, chemical force microscopy and colloidal probe technique is presented. The many applications of the AFS technique for probing surface interactions open up new possibilities to evaluate adhesion, an important characteristic of materials.
Thin Solid Films, 2011
The atomic force microscope (AFM) is a powerful tool to investigate surface properties of model systems at the nanoscale. However, to get semi-quantitative and reproducible data with the AFM, it is necessary to establish a rigorous experimental procedure. In particular, a systematic calibration procedure of AFM measurements is necessary before producing reliable semi-quantitative data. In this paper, we study the contributions of the chemical and mechanical surface properties or the temperature influence on the adhesion energy at a local scale. To reach this objective, two types of model systems were considered. The first one is composed of rigid substrates (silicon wafers or AFM tips covered with gold) which were chemically modified by molecular self-assembling monolayers to display different surface properties (methyl and hydroxyl functional groups). The second one consists of model polymer networks (cross-linked polydimethylsiloxane) of variable mechanical properties. The comparison of the force curves obtained from the two model systems shows that the viscoelastic contributions dominate for the adhesion with polymer substrates, whereas, chemical contributions dominate for the rigid substrates. The temperature effect on the adhesion energy is also reported. Finally, we propose a relation for the adhesion energy at the nanoscale. This relation relates the energy measured during the separation of the contact to the three parameters: the surface properties of the polymer, the energy dissipated within the contact zone and the temperature.
New Approach to the Study of Particle–Surface Adhesion Using Atomic Force Microscopy
Journal of Colloid and Interface Science, 2000
The colloidal probe technique is commonly employed to determine the adhesion force between a particle and a solid surface. Characterization of the adhesion of a particle across a surface can be as important, if not more so, as the determination of an average value for the adhesion. Unfortunately, the measurement of the variation in adhesion can be difficult at best. A new approach for studying particle-surface adhesion based on the force-volume technique is presented. Upon combining the force-volume technique with a colloidal probe, not only is it possible to determine the average adhesion force, but an image of the spatial variation of the adhesion can also be obtained. This method is envisioned to have great potential for examining and analyzing the adhesion behavior in complex natural and technological systems. C 2000 Academic Press
The influence of instrumental parameters on the adhesion force in a flat-on-flat contact geometry
Applied Surface Science, 2014
Atomic force microscopy (AFM) has been used to measure the adhesion force between a flat Si(0 0 1) wafer and a micrometer sized flat silicon AFM tip. Force-distance curves have been recorded at different setpoints in order to elucidate their individual effect on the derived adhesion force. No dependence of the derived adhesion force on the applied load has been detected, making sure that no plastic changes in the morphology of either tip and/or sample occur. Other setpoints as the residence time of the tip at the substrate, the relative humidity, the size of the tip and the retraction velocity of the tip have been varied systematically. We have found that the adhesion force depends strongly on the velocity of the z-piezo and the tip size while, at least within the 0.5-41 s time window, the residence time does not have any measurable effect on the adhesion force. The time scale of the retraction varies between 0.2 and 25 s. The increase of the adhesion force with increasing retraction speed is ascribed to the viscous force. Finally, the adhesion force increases with increasing relative humidity.
Determination of adhesion forces between smooth and structured solids
Applied Surface Science, 2012
Surfaces tend to be made smoother in order to gain flatness or in order to fulfill the need for more precise and reproducible positioning of parts. Adhesion or even sticking of the surfaces is a major showstopper for these applications. There are several measures that can be taken in order to reduce spontaneous adhesion. Quantification of the effectiveness of the chosen solution is most often done using an atomic force microscope (AFM) with probes varying from 1 nm to 8 m of contact diameter. A serious disadvantage in measuring adhesion by sharp tips is the wear of the tips. Sharp tips wear easily, resulting in undefined contact areas. When the real area of contact is not well defined, the quantification of the adhesion force is not significant.
International Journal of …, 2012
The increasing importance of studies on soft matter and their impact on new technologies, including those associated with nanotechnology, has brought intermolecular and surface forces to the forefront of physics and materials science, for these are the prevailing forces in micro and nanosystems. With experimental methods such as the atomic force spectroscopy (AFS), it is now possible to measure these forces accurately, in addition to providing information on local material properties such as elasticity, hardness and adhesion. This review provides the theoretical and experimental background of AFS, adhesion forces, intermolecular interactions and surface forces in air, vacuum and in solution.