The esem used to image crystalline structures of polymers and to image ink on paper

Abstract

This article describes two cases in which the advantages of the ESEM have been exploited in unanticipated ways. First, we have found that etching occurs as the electron beam scans the surface of uncoated polymers in the ESEM. The surface topography caused by this etching, as seen in ESEM images, reflects the morphology of crystalline structures in the polymers. This technique has been valuable in the study of such textures in polymers. The second application is related to our use of the ESEM in support of research on the deinking of paper. In this effort we have learned that an unconventional contrast mechanism can be used during ESEM imaging to distinguish between inked and non-inked areas of newsprint. Under usual operating conditions, ESEM imaging does not distinguish between inked and non-inked areas. However, at relatively low sample chamber pressures the non-inked areas appear brighter than inked areas in ESEM images.

Network morphology of straight and polymer modified asphalt cements

“…In their studies, Rask et al (1993) allowed the electron beam to scan over a selected area which appeared to preferentially remove the amorphous regions and thereby revealed the spherulitic crystals in the polypropylene. The crystals observed by Rask et al (1993) were similar to those observed in previous investigations of polypropylene using chemical etching techniques (Bartisiewicz and Menciz, 1974;Fitchmum and Newman, 1970;Kojima and Satake, 1982;Wu, 1982). Thus, Rask et al (1993) concluded that the crystals were not an artifact due to electron beam heating and subsequent recrystallization of the sample.…”

“…As discussed later, it is difficult to accurately calculate the exact temperature rise in the sample due to beam exposure; therefore, empirical studies are worthwhile to estimate the temperature increase due to beam exposure. Recently the ESEM was used to investigate the crystalline structure of polypropylene and PVC by a beam etching technique (Rask et al, 1993). In their studies, Rask et al (1993) allowed the electron beam to scan over a selected area which appeared to preferentially remove the amorphous regions and thereby revealed the spherulitic crystals in the polypropylene.…”

“…Recently the ESEM was used to investigate the crystalline structure of polypropylene and PVC by a beam etching technique (Rask et al, 1993). In their studies, Rask et al (1993) allowed the electron beam to scan over a selected area which appeared to preferentially remove the amorphous regions and thereby revealed the spherulitic crystals in the polypropylene. The crystals observed by Rask et al (1993) were similar to those observed in previous investigations of polypropylene using chemical etching techniques (Bartisiewicz and Menciz, 1974;Fitchmum and Newman, 1970;Kojima and Satake, 1982;Wu, 1982).…”

Environmental scanning electron microscopy and microanalysis

“…For an ideal gas, the number density is proportional to the specimen chamber pressure by Po (6) n o -kT ~ , and Eq. (4) becomes…”

“…Surface properties of various materials can be studied by observing the wetting properties and differential hygroscopicity on a microscale [5]. Ink on paper can be easily seen since the secondary electron imaging mode is sensitive to and allows the differentiation of surface layers [6]. Energy dispersive spectroscopy and microanalysis in ESEM has demonstrated new uses and great promise [7,8].…”