Polymer Characterization — Chain Dimensions, Structures, and Morphology

Polymer Characterization — Chain Dimensions, Structures, and Morphology 255... 

Small-angle neutron scattering (SANS) is also used for characterizing structure in reactive systems. With SANS (using angles <2°) one can examine polymer morphology and chain dimensions, typically enhanced by deuteratation (which enhances differences in... 

In the context of morphology, the principal information that is obtained from such experiments is the conformational distribution of the polymer chains. In recent years, microscopes have been developed which allow the simultaneous observation of the surface and spectroscopic examination of the surface. The illuminating beam is brought down the optical axis and the reflected light is then collected using fibre optics. The spot size is typically several tens of micrometres but can be smaller and does allow characterization of domains or phase structure that has dimensions of this order. The techniques and their application are covered in detail elsewhere. ... 

Increasing molecular mobility by heating the polymers was not possible because the polymers decomposed before melting. The morphology of none of the spin-coated solid films changed over time, even when the films were heated to 200°C for 60 min. The films were therefore exposed to solvent vapor and turned into concentrated polymer solutions, in order to enable the polymer chains to move, which, in turn, facilitated the structure formation processes. Finally, after structure formation, the dry samples were characterized in detail by OM (Leitz, Metallux 3, Germany) and AFM (Dimension 3000, Nanoscope HI, Veeco, USA) in the tapping mode (TM-AFM). 

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