Polymer Microscopy

The use of atomic force microscopy as an important technique to analyze the dispersion of nanometric fillers and morphology in nanocomposites and polymer blends based on elastomers

“…The main factors of mechanical energy dissipation of the tip and consequent phase change are the viscoelastic, adhesive and topographical properties of the region being examined. In addition, it allows to obtain new information about the polymers surface such as tribological data [3] , local contaminants [6] , morphology [17, , distribution of phases in blends and composites [41][42][43][44][45][46][47] , compatibility between the phases of polymer blends and interaction between nanocomposites phases [48][49][50][51][52][53][54] , polymeric chains conformation [7,38] , cross-link density [55][56][57] , dispersion of fillers in the polymeric matrix [10,12,16,48,49,[58][59][60][61][62][63][64][65][66][67][68][69] , among other applications.…”

“…For surface imaging, the tip deflection will change the direction of the reflected laser beam, changing the intensity difference between the top and bottom sets of photo detectors (AFM signal) [4][5][6] .…”

“…The modes of obtaining the images, also called scanning modes, refer fundamentally to the distance kept between the probe (tip) and the sample during scanning, the ways the tip moves on the surface of the sample and the forces between the sample and tip [6,7] . Three different modes are possible: non-contact, contact and tapping mode.…”

Physical and chemical changes in polystyrene during electron irradiation using EELS in the TEM: contribution of the dielectric function

“…X-ray absorption spectroscopy (XAS) and electron energy-loss spectroscopy (EELS) are powerful techniques used to probe the local chemical and electronic structure of carbon-based materials at a submicrometre spatial resolution (Isaacson & Johnson, 1985;Outka & Stöhr, 1988;Sawyer & Grubb, 1996). XAS is estimated to produce three orders of magnitude less damage than does EELS, and its energy resolution is excellent (a few meV), but its spatial resolution is limited (Ϸ 50 nm with the synchrotron radiation; Ade et al, 1992;Ade, 1994).…”

On the similarity of macromolecular responses to high-energy processes: mechanical milling vs. irradiation

“…An unexpected implication of our findings is that the molecular response of polymers subjected to high-energy ball milling appears mechanistically similar to that resulting from high-energy irradiation. While studies addressing highenergy solid-state polymer processing are scarce, those aimed at elucidating the effect of radiation damage on polymers are voluminous, since they reflect the importance of high-energy radiation in polymer processing and characterization [20][21][22]. High-energy irradiation typically promotes chain scission and/or crosslinking in organic media, thereby affecting the molecular weight and molecular weight distribution of most polymers, and likewise induces collapse of the crystalline structure in semicrystalline polymers [23,24].…”