AFM surface imaging

ATM imaging in the contact mode and in the friction mode was done with a Nanoscope 111 A from Digital Instruments (Santa Barbara, USA) using a 100 xm piezoelectric scanner. The cantilevers used were characterized by a spring constant of 0.16Nm . A standard pyramidal tip of silicon nitride was used. The measurements were carried out in air and at a constant force in the 10 to 10 N range. 

7 Surface Modification of Pebax Membrane by Cold Plasma 

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Fig. 3.82 Pore creation through 13 tm thick PET membranes exposed to 254 and 312 nm wavelengths for 1 h. Ion beam of 58Ni with incident energy 10.7 MeV/u (1 h, 254 nm) 9.1 MeV/u (15 h, 254 nm). Etching occurs at the both faces, d is the pore diameter measured with AFM (surface image) and he is the depth of etching penetration through the membrane measured with SEM (cross-section image) and fe = etching time. Reproduced with permission from [173]. Copyright 2007. Elsevier...

AFM surface images of coatings with carbon nanotubes before (left) and after 16 days of UV exposures (right). 

The ability to control the position of a fine tip in order to scan surfaces with subatomic resolution has brought scanning probe microscopies to the forefront in surface imaging techniques. We discuss the two primary techniques, scanning tunneling microscopy (STM) and atomic force microscopy (AFM) the interested reader is referred to comprehensive reviews [9, 17, 18]. 

The most popular of the scanning probe tecimiques are STM and atomic force microscopy (AFM). STM and AFM provide images of the outemiost layer of a surface with atomic resolution. STM measures the spatial distribution of the surface electronic density by monitoring the tiumelling of electrons either from the sample to the tip or from the tip to the sample. This provides a map of the density of filled or empty electronic states, respectively. The variations in surface electron density are generally correlated with the atomic positions. 

At their highest sensitivities, STM and AFM generate images that show how atoms are arranged on the surfaces they probe. At first, scientists used these tools to explore how atoms are arranged on surfaces. The example below shows individual atoms on the surface of nickel metal. 

Figure 3 Composite HRSEM AFM error images of ibidem measurements taken of the surface of zeolite A. The line in green represents the cross section shown in (D)...

Fig. 4. AFM deflection image of the Cu(lll) surface during deposition of copper. The steps are one atom in height. In the upper left are two nested spiral terraces. 

AFM can image surfaces of a wide range of biological material. 

Fig. 16 (a) Three-point-star DNA motif with sticky ends, formed by seven sequences, (b) Two families of such motifs can bind and yield a two-dimensional array, (c) AFM imaging of the structure in (b) the inset shows the associated Fourier pattern. Adapted with permission from [72]. (d) DNA 4x4 tile structure (nine sequences) two different tiles can produce a square lattice (e). (f) AFM surface plot of the structure in (e), edge size is 150 nm. Adapted with permission from [73]... 

Fig. 6 Overview of the wavelength ranges that can be routinely achieved using the various modification techniques of PDMS surfaces. The inset displays a 3-D AFM height-image of a plasma-modified surfaces...

Fig. 16 Top-. Summary of the p.CP process using wrinkled stamps. Bottom AFM height-images 5 x 5 Llm (height scale AZ= 15nm) of surfaces, which are patterned via pCP by the use of wrinkled stamps with different periodicities and heights. With increasing features of the stamp, the stripes of the pattern broaden and separate, (a) A/X 25/302 nm, (b) A/X 40/355nm, (c) A/X 60/426 nm, A) A/X 100/603 nm, (c)A/X 150/743 nm, (f)A/X 200/931 nm) [48]...

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