Testing methods atomic force microscopy

In conclusion, it should be pointed out that none of the physicochemical techniques discussed above permits the direct measurement of the elements of the polymeric materials porous structure we measure the properties of the systems where the polymers interact with certain test substances (nitrogen, mercury, water, polystyrene standards, ions, etc.), and not the dimensions of the pores or other supramolecular elements of the material. Therefore, the evaluation of the surface area and diameters of pores available to the molecules of these substances must be considered as indirect methods of examining the porous structure. Because of this, all calculations are based on assuming certain models of the structure of the material and accepting certain assumptions as to the mechanism of interaction between the material and test molecules. Only transmittance, scanning, and, in particular, atomic force microscopy can be considered as direct methods of measuring dimensions and distances. However, up to now the last technique has not been appHed to microporous hypercrosslinked polymers. 

The characterization techniques of MD membranes are physical methods, which can be divided in two main groups (i) the techniques related to membrane permeation such as liquid and gas flow tests and (ii) the techniques permitting to obtain directly the morphological properties of the membranes, including scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). 

Many techniques have been developed to measure the Young s modulus and the stress of the mesoscopic systems [12, 13]. Besides the traditional Vickers microhardness test, techniques mostly used for nanostructures are tensile test using an atomic force microscope (AFM) cantilever, a nanotensile tester, a transmission electron microscopy (TEM)-based tensile tester, an AFM nanoindenter, an AFM three-point bending tester, an AFM wire free-end displacement tester, an AFM elastic-plastic indentation tester, and a nanoindentation tester. Surface acoustic waves (SAWs), ultrasonic waves, atomic force acoustic microscopy (AFAM), and electric field-induced oscillations in AFM and in TEM are also used. Comparatively, the methods of SAWs, ultrasonic waves, field-induced oscillations, and an AFAM could minimize the artifacts because of their nondestructive nature though these techniques collect statistic information from responses of all the chemical bonds involved [14]. 

---