Scanning Electron Microscopy Measurements of the Surface Roughness of Paper

Abstract

A new approach to the measurement of x−y uniformity of the surface of a paper sheet is described. Scanning electron micrographs are taken of both the top and bottom surfaces of a paper sheet and image-analyzed. The images were converted to grayscale, and the standard deviation of the pixel brightness was called the “SEM roughness index” and calculated for each surface. Both commercial newsprint sheets and handsheets made with kraft, TMP, and recycled fibers were examined. Debonders and cationic polymers were added to some sheets. The addition of debonders increases the index on the top side of the sheet but decreases it on the bottom. This is caused by the movement of fines from the top to the bottom side. The addition of cationic polymers increases the SEM roughness index by increasing the degree of microfloc formation. Samples taken across a reel from a commercial paper machine tend to show a mirror image relationship between the top and bottom surfaces. The SEM roughness index is able to detect subtle changes in sheet structure caused by differences in the mode of addition of polymers used for retaining fines in the sheet.

Study on the structure and vacuum membrane distillation performance of PVDF composite membranes: I. Influence of blending

“…SEM images were digitized to 8-bit grayscale images by employing Image J software [18,19]. Then 256-level histograms of those SEM images were converted from plotting the pixel brightness data for each image.…”

Nucleation kinetics of paracetamol–ethanol solutions from induction time experiments using Lasentec FBRM®

“…The degree of diffuse reflection from an interface, is mainly affected by the surface roughness, with rough surfaces displaying a higher level of diffuse reflection, compared to smoother surfaces [27]. Scanning electron microscopy (SEM) has been shown to provide a measure of the surface roughness of a given sample, with the brightness of the SEM image providing an indication of depth [29,30]. In order to ensure that the surface roughness of the paracetamol crystals and the ceramic beads is similar, SEM analysis was conducted.…”

Antibacterial Drug-Release Polydimethylsiloxane Coating for 3D-Printing Dental Polymer: Surface Alterations and Antimicrobial Effects

“…The pixel brightness data of each image were plotted as 256-level histograms to build a surface plot image, where the y-axis represents the 0–255 grayscale levels and the x-axis represents the pixel frequency. The histograms from all 10 images were combined, and the standard deviation of the pixel brightness was calculated as the SRI [ 47 ].…”