Imaging of Polymer Morphology

The AFM techniques briefly introduced above provide direct real-space access on structures and phases on all relevant length scales of hierarchical ordering of polymers. The subsequent sections shall not encompass all possible structures and examples of polymer morphology, but rather focus on selected examples that illustrate the rich information extracted from AFM. These examples include classic morphologies, as well as more recently reported polymeric nano- and microstructures. 

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M. R. Libera, Imaging unstained polymer morphology using electron energy-loss spectroscopy. Abstracts of Papers. In 224th ACS National Meeting 2002 Aug 18-22 Boston (MA). 

Fig. 2.20 Examples of electron micrographs of polymers, (a) A defocussed bright-field image of a thin film of isotactic polystyrene annealed and crystallised at about 170 °C (b) An image of a fracture surface replica from a sample of linear polyethylene crystallised from the melt at 4.95 kbar. ((a) Adapted by permission of Masaki Tsuji and (b) adapted from Principles of Polymer Morphology by D. C. Bassett. Cambridge University Press 1981.)...

Figure 25.6 Transmission electron microscopy images of polymer particles, illustrating the particle morphology during the early stages of emulsion polymerizations of methyl methac late (Al, 2 min after initiation A2, 8 min after initiation, potassium peroxodisulfate, scale bars = 200 nm), styrene (B1 initiator potassium...

Scanning electron microscopy (SEM) of microcapsules from which HD is extracted have been studied to understand the extent of encapsulation. One-hole, large-hole and half-moon morphologies imply that HD is not encapsulated completely by polymer, whereas a hollow morphology indicates complete encapsulation. Figure 5.8 shows SEM images of polymer microcapsules as a function of HD amount at lower monomer conversion (without DMAEMA). In the absence of DMAEMA, one-hole or... 

Features images of phase morphology in filler/polymer composites and nanocomposites... 

As described below, the HAS-derived nitroxides in heterophasic polymer systems perform a triple role. First, they provide the contrast needed in the imaging experiments. Second, they enable the visualization of polymer morphology, based on the detection of two dynamically different components detected in the ESR spectra of the nitroxides in ABS, for example, the two sites, fast (F) and slow (S), have been assigned to location of nitroxides in butadiene-rich and styrene-acrylonitrile (SAN)-rich domains, respectively. Third, the spatial variation of the ESR spectra of nitroxides (in terms of intensity and line shapes) with treatment time, t, provides detailed information on the extent of degradation in the different miCTodomains. These experiments made possible the determination of the concentration profiles of the nitroxides from ID ESRl, and also of the spectral profiles from 2D spectral-spatial ESRI, both in a nondestructive way. In these studies the nitroxides, which are the contrast agents, are part of the systan therefore these studies represent the evolution of ESRl techniques beyond phantoms. 

Fig. 1.1 SEM images of different morphologies obtained for synthetic polymers (a polymethylmethacrylate b polystyrene c polyphenylacetylene d, e poly(Af,Af-dimethylpropargylamine derivatives f Pt-polymetaUayne) and biopolymers (g chitosan h, i, 1, m hyaluronic acid derivatives n dextran) (Reprinted with permission from Chronopoulou et al. [8]. Copyright 2009 American Chemical Society)...

In this chapter an overview is presented of the application of EM to morphological studies of polymer blends, with special emphasis on sample preparation and comparative studies using AFM. A brief overview of sample preparation is first provided, followed by some typical characterizations of polymer blends, based on the present author s experience, research data, and information reported elsewhere. It should be noted that only the imaging of polymer blend structures will be described at this point, since the assodated spectroscopic tools and chemical mapping are beyond the scope of the chapter. 

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