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Modelling clustering of vertically aligned carbon nanotube arrays.

Schaber CF, Filippov AE, Heinlein T, Schneider JJ, Gorb SN - Interface Focus (2015)

Bottom Line: Previous research demonstrated that arrays of vertically aligned carbon nanotubes (VACNTs) exhibit strong frictional properties.To better understand the experimentally obtained results, we formulated and numerically studied a minimalistic model, which reproduces the main features of the system with a minimum of adjustable parameters.The data obtained by the model calculations coincide very well with the experimental data and can help in adapting VACNT arrays for biomimetic applications.

View Article: PubMed Central - PubMed

Affiliation: Functional Morphology and Biomechanics, Zoological Institute , Kiel University , Am Botanischen Garten 1-9, 24118 Kiel , Germany.

ABSTRACT
Previous research demonstrated that arrays of vertically aligned carbon nanotubes (VACNTs) exhibit strong frictional properties. Experiments indicated a strong decrease of the friction coefficient from the first to the second sliding cycle in repetitive measurements on the same VACNT spot, but stable values in consecutive cycles. VACNTs form clusters under shear applied during friction tests, and self-organization stabilizes the mechanical properties of the arrays. With increasing load in the range between 300 µN and 4 mN applied normally to the array surface during friction tests the size of the clusters increases, while the coefficient of friction decreases. To better understand the experimentally obtained results, we formulated and numerically studied a minimalistic model, which reproduces the main features of the system with a minimum of adjustable parameters. We calculate the van der Waals forces between the spherical friction probe and bunches of the arrays using the well-known Morse potential function to predict the number of clusters, their size, instantaneous and mean friction forces and the behaviour of the VACNTs during consecutive sliding cycles and at different normal loads. The data obtained by the model calculations coincide very well with the experimental data and can help in adapting VACNT arrays for biomimetic applications.

No MeSH data available.


Related in: MedlinePlus

Predicted (small solid dots) and experimentally determined (open circles) values of (a) the number of clusters after five consecutive sliding cycles and (b) the friction coefficient at the first sliding cycle at different normal loads Fn on the surface of the arrays. The model data are overdrawn from six runs of the code with the same parameters.
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RSFS20150026F7: Predicted (small solid dots) and experimentally determined (open circles) values of (a) the number of clusters after five consecutive sliding cycles and (b) the friction coefficient at the first sliding cycle at different normal loads Fn on the surface of the arrays. The model data are overdrawn from six runs of the code with the same parameters.

Mentions: Evaluating the model for the experimentally observed decrease of the number of clusters (corresponding to an increase of their sizes) with increasing normal loads, there is good agreement of the results (figure 7a). The same is true for the decrease of the friction coefficient with increasing normal force (figure 7b).Figure 7.


Modelling clustering of vertically aligned carbon nanotube arrays.

Schaber CF, Filippov AE, Heinlein T, Schneider JJ, Gorb SN - Interface Focus (2015)

Predicted (small solid dots) and experimentally determined (open circles) values of (a) the number of clusters after five consecutive sliding cycles and (b) the friction coefficient at the first sliding cycle at different normal loads Fn on the surface of the arrays. The model data are overdrawn from six runs of the code with the same parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590422&req=5

RSFS20150026F7: Predicted (small solid dots) and experimentally determined (open circles) values of (a) the number of clusters after five consecutive sliding cycles and (b) the friction coefficient at the first sliding cycle at different normal loads Fn on the surface of the arrays. The model data are overdrawn from six runs of the code with the same parameters.
Mentions: Evaluating the model for the experimentally observed decrease of the number of clusters (corresponding to an increase of their sizes) with increasing normal loads, there is good agreement of the results (figure 7a). The same is true for the decrease of the friction coefficient with increasing normal force (figure 7b).Figure 7.

Bottom Line: Previous research demonstrated that arrays of vertically aligned carbon nanotubes (VACNTs) exhibit strong frictional properties.To better understand the experimentally obtained results, we formulated and numerically studied a minimalistic model, which reproduces the main features of the system with a minimum of adjustable parameters.The data obtained by the model calculations coincide very well with the experimental data and can help in adapting VACNT arrays for biomimetic applications.

View Article: PubMed Central - PubMed

Affiliation: Functional Morphology and Biomechanics, Zoological Institute , Kiel University , Am Botanischen Garten 1-9, 24118 Kiel , Germany.

ABSTRACT
Previous research demonstrated that arrays of vertically aligned carbon nanotubes (VACNTs) exhibit strong frictional properties. Experiments indicated a strong decrease of the friction coefficient from the first to the second sliding cycle in repetitive measurements on the same VACNT spot, but stable values in consecutive cycles. VACNTs form clusters under shear applied during friction tests, and self-organization stabilizes the mechanical properties of the arrays. With increasing load in the range between 300 µN and 4 mN applied normally to the array surface during friction tests the size of the clusters increases, while the coefficient of friction decreases. To better understand the experimentally obtained results, we formulated and numerically studied a minimalistic model, which reproduces the main features of the system with a minimum of adjustable parameters. We calculate the van der Waals forces between the spherical friction probe and bunches of the arrays using the well-known Morse potential function to predict the number of clusters, their size, instantaneous and mean friction forces and the behaviour of the VACNTs during consecutive sliding cycles and at different normal loads. The data obtained by the model calculations coincide very well with the experimental data and can help in adapting VACNT arrays for biomimetic applications.

No MeSH data available.


Related in: MedlinePlus