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AFM-IR has also been used to evaluate and map mineral content, crystallinity, collagen maturity and acid phosphate content via ratiometric analysis of various absorption bands in bone. [66] AFM-IR has also been used to perform spectroscopy and chemical mapping of structural lipids in human skin, [75] cells [60] and hair [76]
nc-AFM was the first form of AFM to achieve true atomic resolution images, rather than averaging over multiple contacts, both on non-reactive and reactive surfaces. [ 32 ] nc-AFM was the first form of microscopy to achieve subatomic resolution images, initially on tip atoms [ 42 ] and later on single iron adatoms on copper.
In cellular biology, AFM can be used to attempt to distinguish cancer cells and normal cells based on a hardness of cells, and to evaluate interactions between a specific cell and its neighboring cells in a competitive culture system. AFM can also be used to indent cells, to study how they regulate the stiffness or shape of the cell membrane or ...
Kelvin probe force microscopy (KPFM), also known as surface potential microscopy, is a noncontact variant of atomic force microscopy (AFM). [ 1 ] [ 2 ] [ 3 ] By raster scanning in the x,y plane the work function of the sample can be locally mapped for correlation with sample features.
Topographic (left) and current (right) maps collected with CAFM on a polycrystalline HfO 2 stack. The images show very good spatial correlation. In microscopy, conductive atomic force microscopy (C-AFM) or current sensing atomic force microscopy (CS-AFM) is a mode in atomic force microscopy (AFM) that simultaneously measures the topography of a material and the electric current flow at the ...
The image shows periodically poled 180° domains in potassium titanyl phosphate (KTP) as imaged by VPFM. In the image piezoresponse amplitude can be seen where dark areas represent the zero amplitude that is expected at domain boundaries where the unit cell is cubic i.e. centrosymmetric and so therefore not ferroelectric.
Molecular self-assembly is a key concept in supramolecular chemistry. [6] [7] [8] This is because assembly of molecules in such systems is directed through non-covalent interactions (e.g., hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, pi-stacking interactions, and/or electrostatic) as well as electromagnetic interactions.
In AFM, feedback loops control the operation of the microscope by keeping a fixed value a parameter of the tip's oscillation. [11] If the main feedback loop operates with the amplitude, the AFM mode is called amplitude modulation (AM). If it operates with the frequency shift, the AFM mode is called frequency modulation (FM).