Polymer confocal microscopy characterization

Figure 1.49 shows an example of using confocal fluorescent microscopy to reveal microscopic features in a specimen. The specimen is low density polyethylene (LDPE) containing fluores-cently labeled silica particles. The particle size and distribution in the polymer matrix can be clearly revealed by 3D confocal microscopy. Thus, confocal microscopy provides us a new dimension in light microscopy for materials characterization, even though its applications in materials science are not as broad as in biology. 

The solid phase of bread crumb can be viewed as a composite material where amylose, amylopectin and protein form separated phases due to poor thermodynamic miscibility of the different polymers. Composites are characterized by exhibiting mechanical properties that cannot be achieved with the individual constituents alone, but are dependent on the interface between the components. A sharp interface as found between starch and protein provides strong evidence of little polymer interdiffusion and weak interfacial adhesion.14 The present results suggest that starch forms a continuous phase in bread which has also been confirmed with confocal scanning laser microscopy.15 The presence of a protein phase reduces the continuity of the starch phase and, thus, reduces the cohesion of the material as revealed by a comparison of the breaking stresses of aged flour and starch gels (data not shown).16... 

V.L. Finkenstadt, C.K. Liu, PH. Cooke, L.S. Liu, and J.L. Willett, Mechanical property characterization of plasticized sugar beet pulp and poly (lactic acid) green composites using acoustic emission and confocal microscopy. /. Polym. Environm. 16(1), 19-26 (2008). 

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