Surface potentials, scanning electron microscopy

In contrast to many other surface analytical techniques, like e. g. scanning electron microscopy, AFM does not require vacuum. Therefore, it can be operated under ambient conditions which enables direct observation of processes at solid-gas and solid-liquid interfaces. The latter can be accomplished by means of a liquid cell which is schematically shown in Fig. 5.6. The cell is formed by the sample at the bottom, a glass cover - holding the cantilever - at the top, and a silicone o-ring seal between. Studies with such a liquid cell can also be performed under potential control which opens up valuable opportunities for electrochemistry [5.11, 5.12]. Moreover, imaging under liquids opens up the possibility to protect sensitive surfaces by in-situ preparation and imaging under an inert fluid [5.13]. 

Scanning electron microscopy (SEM) utilizes a highly focused electron beam which is scanned over the surface of the specimen. Since penetration through the specimen is not essential for this instrument, thicker samples (cm range) and lower accelerating potentials (low kV range) are commonly used. The most popular mode of operation is the emissive mode which utilizes those electrons that have either been emitted by the... 

Scanning electron microscopy results showed that the surface aspect, after a potential sweep from -0.9 to 2.0 V at 0.1 V s-1 and a holding at the last potential for 10 min, supported the idea that the film is formed by precipitation (noncontiguous aspect) and presented a porous aspect (see micrograph in Ref. [62]). 

The carboxyhc-type hypercrosslinked resin MN-600 was examined comprehensively by Saha and Streat [388], in comparison with polyacryHc acid C-104E (Purolite), with the aim of evaluating the performance of the resins for trace heavy metal removal. Characterization of these polymers involved scanning electron microscopy, BET and Langmuir surface area measurements, Fourier transform infrared (FTIR) spectroscopy. X-ray photoelectron spectroscopy, elemental analysis, zeta potential... 

To identify nanoparticles there are several analytical techniques, including crystalline nature, surface plasmon resonance, size, shape, stability, nature, etc., which was done by various analytical instruments, such as UV-visible spectroscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis, zeta potential, etc. These are mostly used for analysis of synthesized nanoparticles, which helps us to study crystalline nature, functional groups, and morphological studies, and to identify its stability. 

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