Wetting properties of AFM probes by means of contact angle measurement

Tao, Zhenhua; Bhushan, Bharat

doi:10.1088/0022-3727/39/17/023

Cited by 34 publications

(29 citation statements)

References 14 publications

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“…When in contact with the nanotube suspension drop, the attraction of the sharp tip for the liquid draws the liquid up onto the probe surface. Due to capillarity, the free-liquid surface assumes a shape with a concave meniscus (see image and schematic in Figure 4) with a contact angle of 50-60 degrees for Si or Si 3 N 4 probes comparable to the reported values [34]. The resulting capillary force (f c ) is directly proportional to the surface tension () and perimeter (d), which is balanced by the contraction force (F c ) caused by the nanotube suspension drop (gray dashed lines in Figure 4) that is also the product of surface tension () and corresponding perimeter (D).…”

Section: Tip Geometry Effect On Dielectrophoretic Assembly Of Nanofibsupporting

confidence: 83%

Electric field and tip geometry effects on dielectrophoretic growth of carbon nanotube nanofibrils on scanning probes

Wei¹,

Craig²,

Huey³

et al. 2008

Nanotechnology

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Single-wall carbon nanotube (SWNT) nanofibrils were assembled onto a variety of conductive scanning probes including atomic force microscope (AFM) tips and scanning tunnelling microscope (STM) needles using positive dielectrophoresis (DEP). The magnitude of the applied electric field was varied in the range of 1-20V to investigate its effect on the dimensions of the assembled SWNT nanofibrils. Both length and diameter grew asymptotically as voltage increased from 5-18V. Below 4V, stable attachment of SWNT nanofibrils could not be achieved due to the relatively weak DEP force versus Brownian motion. At voltages of 20V and higher, low quality nanofibrils resulted from incorporating large amounts of impurities. For intermediate voltages, optimal nanofibrils were achieved, though pivotal to this assembly is the wetting behaviour upon tip immersion in the SWNT suspension drop. This process was monitored in situ to correlate wetting angle and probe geometry (cone angles and tip height), revealing that probes with narrow cone angles and long shanks are optimal. It is proposed that this results from less wetting of the probe apex, and therefore reduced capillary forces and especially force transients during the nanofibril drawing process. Relatively rigid probes (force constant  2N/m) exhibited no perceivable cantilever bending upon wetting and dewetting, resulting in the most stable process control.

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Section: Tip Geometry Effect On Dielectrophoretic Assembly Of Nanofibsupporting

confidence: 83%

Electric field and tip geometry effects on dielectrophoretic growth of carbon nanotube nanofibrils on scanning probes

Wei¹,

Craig²,

Huey³

et al. 2008

Nanotechnology

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“…The water meniscus formation around the tip might also make images degradation. Although it can be improved by lowering the relative humidity of AFM chamber, it still exist at 0% relative humidity according to the recent studies, so the meniscus should be considered all the time(Rozhok et al 2004, Jang et al 2004, Tao and Bhushan 2006, Lee et al 2008). …”

Section: Resultsmentioning

confidence: 99%

Gloss phenomena and image analysis of atomic force microscopy in molecular and cell biology

et al. 2009

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Summary Proper sample preparation, scan setup, data collection and image analysis are key factors in successful atomic force microscopy which can avoid gloss phenomena effectively from unreasonable manipulations or instrumental defaults. Fresh cleaved mica and newly treated glass cover were checked firstly as the substrates for all of the sample preparation for atomic force microscopy. Then, crystals contamination from buffer were studied separately or combined with several biologic samples, and the influence of scanner, scan mode and cantilever to data collection were also discussed intensively using molecular and cellular samples. At last, images treatment and analysis with off-line software had been focused on standard and biologic samples, and artificial glosses were highly considered for their high probability in occurring.

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“…However, it is still worth noting that the surface of the cleaned (washed)/functionized probes are hydrophilic, which will increase the adhesive forces between the samples and the probe. In addition, the water meniscus formation around the probe might decline the quality of AFM images and the accuracy of mechanical measurement, which also should be considered in the comparison analysis according to the recent studies (Gan 2009;Lee and Sheehan 2008;Rozhok et al 2004;Tao and Bhushan 2006).…”

Section: Effects On Mechanical Measurements Of Fibersmentioning

confidence: 99%

Effects of probe pollutants on morphological and mechanical measurements of muscle and collagen fibers using atomic force microscopy

et al. 2010

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Because of the interaction between probes and samples, pollutants in buffer solution or in the air would easily bind to probes and make the probe polluted, which might influence the morphological and mechanical measurements with atomic force microscopy. The polluted probes might transfer the pollutants onto the samples and thus change the surface ultrastructure of samples, or collect the deviated feedback signals to make the phantasm images. The former process is irreversible even if a new probe is employed, and the latter one is a reversible process as long as changing the used/polluted probe. Effects of polluted probes on morphological and mechanical characteristics of insect flight muscle and rat tail tendon collagen I fibers had been discussed in this study, in which, we constructed a series of methods to avoid/reduce the collecting of phantasm images and deviated mechanical information, such as changing the scanning direction and scanning force, replacing the new probes, or cleaning the polluted probes.

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Wetting properties of AFM probes by means of contact angle measurement

Cited by 34 publications

References 14 publications

Electric field and tip geometry effects on dielectrophoretic growth of carbon nanotube nanofibrils on scanning probes

Electric field and tip geometry effects on dielectrophoretic growth of carbon nanotube nanofibrils on scanning probes

Gloss phenomena and image analysis of atomic force microscopy in molecular and cell biology

Effects of probe pollutants on morphological and mechanical measurements of muscle and collagen fibers using atomic force microscopy

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