SPM Probes

Choosing the appropriate SPM probe depends on a number of factors, primarily on the intended application. For example, tips may be coated with metal for specific applications (e.g. with Au/Pt or Cr/Au for EFM, with Co or Ni for MFM) or with hard coatings such as diamond-like carbon (DLC) or SiC for extra durability. Note that these coatings generally compromise tip sharpness to some extent. 

For AFM, both the tip and its supporting cantilever must be considered. The key factors to be considered are materials of construction. 

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Modifications of LB films, whether caused by the SPM probe or by some other external force, are easily characterized and can provide insight into film structure and -dynamics. With an AFM tip under high force it is possible to maike holes in an LB film. From the image of the hole the thickness per monolayer and number of monolayers can be determined. Virtanen et al. ) induced defect pores in bllayers of stearic acid and cadmium stearate by the application of electric pulses between an STM tip and film surface. Real-time STM images measuring the rates at which these pores refill , provide a means of determining the viscosity of nanometer-scale regions of deposited molecular films. 

Tip holder Removable appliance for mounting SPM probes (on AFMs, the tip holder is installed within the head of the microscope)... 

Ge, Y., Zhang, W., Chen, Y.-L., et ah, 2013. A reproducible electropolishing technique to customize tungsten SPM probe from mathematical modeling to realization. J. Mater. Proc. Technol. 213, 11-19. 

FIGURE 1.53 SPMs. Probe can operate both in air and liquid media. 

First attempts to record the micro/nanomechanical surface properties with atomic force microscopy/scanning probe microscopy (AFM/SPM) probing were conducted by using the classical Sneddon s approach [1-3]. Further development lead to the micromapping of the surface mechanical properties with a force modulation mode [4-8]. Several studies were focused on the development of dc force-displacement probing of the micromechanical properties [9-15]. In this communication, we report on studies of the micromechanical properties of composite films of polystyrene/polybutadiene (PS/PB) and grafted PS layers and prove the feasibility of... 

An original outcome of the combination of microfluidics and apertured SPM probes is the development of FluidFM, which exploits the liquid dispensing directly at or close to a sharp atomic force microscope tip to deliver the solution on or through the cytoplasmic membrane of living cells in a liquid environment. The sensitive force feedback inherited from the SPM configuration provides a convenient way to approach the tip to the fluid membrane... 

Spatial positioning and control of the SPM probe with respect to the surface need to be considered in three contexts ... 

Central to all SPMs (or local probe methods , or local proximal probes as they are sometimes called) is the presence of a tip or sensor, typically of less than 100 mn radius, that is rastered in close proximity to—or in contact with—tire sample s surface. This set-up enables a particular physical property to be measured and imaged over the scaimed area. Crucial to the development of this family of teclmiques were both the ready availability of piezoelements, with which the probe can be rastered with subnanometre precision, and the highly developed computers and stable electronics of the 1980s, without which the operation of SPMs as we know them would not have been possible. 

STM and SFM belong to an expanding family of instruments commonly termed Scanning Probe Microscopes (SPMs). Other common members include the magnetic force microscope, the scanning capacitance microscope, and the scanning acoustic microscope. ... 

The three-dimensional, digital nature of SFM and STM data makes the instruments excellent high-resolution profilometers. Like traditional stylus or optical profilometers, scanning probe microscopes provide reliable height information. However, traditional profilometers scan in one dimension only and cannot match SPM s height and lateral resolution. 

Tortonese, M. and Kirk, M., Characterization of application specific probes for SPMs. SPIE, 3009, 53-60(1997). 

FIGURE 9.14 Typical approach force curve (solid line) for a sample which is penetrated by the scanning probe microscope (SPM) tip. Also shown is the force curve (dashed line) when the tip encounters a hard surface (glass) and schematic drawings of the relative positions of the SPM tip and the sample surface as related to the force curves. (From Huson, M.G. and Maxwell, J.M., Polym. Test., 25, 2, 2006.)... 

In the current work a Digital Instmments Dimension 3000 SPM was operated in force-volume mode using a probe with stiffness selected to match the stiffness of the sample. Standard silicon nitride probes with a nominal spring constant of 0.12 or 0.58 N/m were used for recombinant and native resilin samples. These samples were characterized in a PBS bath at a strain rate of 1 Hz. For synthetic rubbers, silicon probes with a nominal spring constant of 50 N/m were used and the material was characterized in air. Typically, at least three force-volume plots (16 X 16 arrays of force-displacement curves taken over a 10 X 10 p.m area) were recorded for each of the samples. 

FIGURE 9.16 Resilience values for chlorobutyl rubber (CIIR), butadiene rubber (BR), unfilled natural rubber (NR), filled natural rubber (SRB), and polyurethane (PU) samples tested using a Shore rebound resibometer, an Instron compression tester and a scanning probe microscope (SPM). (From Huson, M.G. and Maxweb, J.M.,... 

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