AFM manufacturers

JPK Instruments AG Bouchestrasse 12 Haus 2, Aufgang C 12435 Berlin, Germany http //www.jpk.com 

Pacific Nanotechnology 3350 Scott Blvd., 29 Santa Clara, CA 95054, USA http //www.pacificnanotech.com/ 

Nanosurf AG Grammetstrasse 14 4410 Liestal, Switzerland http //www.nanosurf.com/ 

WITec Wissenschaftliche Instrumente und Technologie GmbH Horvelsinger Weg 6 D-89081 Uhn, Germany http //www.witec.de/ 

KANC 4F, Iui-Dong, 906-10 Suwon 443-270, Korea Homepage www.parkAFM.co.kr http //www.parkafm.com 

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The surface topography of the obtained MDF cement specimens was studied by AFM (NT-MDT model NTGRA PREVIA EC), operated at ambient atmosphere. AFM data were collected in semi contact mode using a silicone cantilever (CSG 10, force constant 0.15 N/m, tip radius 10 nm). The average roughness was calculated with the AFM manufacturer s provided software on images of 5 x 5 pm scan size. 

In 2009, long-time AFM manufacturers Park Systems (Suwon, South Korea) developed an SICM instrument geared specifically toward live cell imaging. This system integrates SICM, noncontact AFM, and optical microscopy into one instrument. The system also allows for electrophysiological patch-clamp measurements and can function in approach retract scan mode, which is similar to hopping mode. A specialized environmental chamber for temperature, pH, and humidity control is available, which can help to keep cells viable for longer than 20 h. 

For any AFM experiment, and also the interpretation of AFM data, an appreciation of the underlying fundamental AFM techniques and their opportunities and limitations is required. This statement refers in the context of this chapter to the rudimentary imaging meehanisms involved. More detailed treatments on specific aspects, including the underlying physics, have been published and the reader is referred to these reviews [13], handbooks [6], and the exaet specifications of the AFM manufacturers. 

The physical characterisation of membrane structure is important if the correct membrane is to be selected for a given application. The pore structure of microfiltration membranes is relatively easy to characterise, SEM and AFM being the most convenient method and allowing three-dimensional structure of the membrane to be determined. Other techniques such as the bubble point, mercury intrusion or permeability methods use measurements of the permeability of membranes to fluids. Both the maximum pore size and the pore size distribution may be determined.1315 A parameter often quoted in manufacturer s literature is the nominal... 

AFM probes with tip having rounded apex whose diameter is in the 50-150 nm are available from two probe manufacturers (Team Nanotec, http //www.team-nanotec.de/) and Nanoworld (http //www. nanoworld.com). 

One point, which is often disregarded when nsing AFM, is that accurate cantilever stiffness calibration is essential, in order to calculate accurate pull-off forces from measured displacements. Althongh many researchers take values quoted by cantilever manufacturers, which are usually calculated from approximate dimensions, more accurate methods include direct measurement with known springs [31], thermal resonant frequency curve fitting [32], temporary addition of known masses [33], and finite element analysis [34]. 

Fig. 21 a Fluorescence images of xCP-immobilized fluorescein labeled ONDs on a glass surface. The pattern size is limited only by the use of manufactured molds with the desired feature size, b AFM images of stamped 1 p.m lines of 20-bp ONDs (left) and 500bp PCR fragments (right) on mica substrates [79]. Reprinted with permission... 

Similarly, STMs are being developed commercially at an astonishing speed. As of summer 1991, over 30 companies have manufactured and marketed STMs and parts. Many beginning companies dedicated to STMs and AFMs are seeing their business expand rapidly. The recent performance of Digital Instruments, Park Scientific Instruments, WA Technology, Angstrom... 

Membranes are very finely porous structures and like all such porous structures used in an industrial context are susceptible to fouling caused by adhesion of components of the materials being processed. This fouling can be minimised or avoided if suitable polymers are used in membrane manufacture. However, the selection of membrane polymers suited to particular separations has until now been a matter of experience (and failure) rather than science. However, an AFM used with the colloid probe technique [23] can provide a rapid means of assessing the adhesion of solutes to membrane materials and is hence a powerful tool for the membrane technologist. 

An AFM apparatus, PicoSPM manufactured by Molecular Imaging (MI), which is schematically shown in Fig.l, was used. The benefit of this apparatus is the top-down... 

For this purpose, the cantilever tune menu is opened and a frequency sweep is performed. From the probe manufacturers data sheet, the resonance frequency is approximately known, e.g., 300 kHz. Hence, we excite the lever with low power (drive amplitude 25 mV) and sweep the frequency for 30 kHz around the expected resonance frequency of 300 kHz. In advanced AFM set-ups, the resonance frequency may also be independently determined before the tuning by a thermal tune (please consult the corresponding manual for details the procedure is globally reviewed in Sect. 2.2.5). 

Much work has been invested in AFM tips in order to improve resolution further. Singlewall carbon nanotubes offer higher resolution than conventional tips as they combine extremely small size with low adhesion to the sample surface. They also buckle rather than break when put under stress and are very durable. Flowever, one hurdle to their use is the expense and difficulty involved in fabricating them, which has made their manufacture a new area of research ". ... 

Nanosurf, which manufactures portable SPM instruments, has been selected by NASA to join a consortium to equip a Mars lander with an AFM in 2007 . The AFM weighs only 300 g and its power consumption is less than 10 W. The AFM scanner is... 

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