Generalized Analysis Approach of the Profile Roughness by Electron Microscopy with the Example of Hierarchically Grown Polystyrene–Iron Oxide–Silica Core–Shell–Shell Particles

Abstract

The roughness as a property of core–shell (CS) microparticles plays a key role in their functionality. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task with approaches using electron microscopy images being scarce and showing pronounced differences in terms of methodology and results. This work presents a generalized method for the reliable roughness determination of nonplanar specimens such as CS particles from electron microscopic images, the method being robust and reproducible with a high accuracy. It involves a self‐written software package (Python) that analyzes the recorded images, extracts corresponding data, and calculates the roughness based on the deviation of the identified contour. Images of single particles are taken by a dual mode scanning electron microscopy (SEM) setup which permits imaging of the same field‐of‐view of the sample with high resolution and surface sensitive in SE InLens mode as well as in transmission mode (TSEM). Herein, a new type of polystyrene core–iron oxide shell–silica shell particles is developed to serve as a set of lower micrometer‐sized study objects with different surface roughness; the analysis of their images by the semiautomatic workflow is demonstrating that the particles’ profile roughness can be quantitatively obtained.

Assembly of Zinc‐Single‐Site‐Containing Silica Nanoparticles to Supraparticle Powders with Destructibility to Serve as Filler and Vulcanization Activator in Rubbers

“…Formula (1) was used to calculate the RMS-roughness (root mean square-roughness) as the standard deviation of all radii. [24] RMS − roughness =…”

Rapid Prototyping of High-resolution Large Format Microfluidic Device Through Maskless Image Guided In-situ Photopolymerization

“…The last important parameter in consideration for this application is the roughness of the patterns. The roughness of the printed pillars has been analyzed from over 50 pillars by measuring the distance of the edge of the pillars from the center at 3.6º intervals following the image processing algorithm explained in another study 61 . The process and radius measurement are shown in Figure 4(i-j).…”

“…Pillars generated with the proposed method have much better smoothness over PDMS patterns made from a SU8 mold generated by standard photolithography using a 64k DPI chrome mask. The Root Mean Square (RMS) value of the deviation of the distances from the center provides a quantitative measure of the roughness 62,63 . For this case, the RMS of the pillar diameter for PEGDA and PDMS devices are 0.79 µm and 1.99 µm, respectively, meaning PEGDA has a much smoother side surface profile than PDMS devices.…”

From 2D and Single Particle to 3D and Batch Analysis as a Routine Quality Check Procedure for the Morphological Characterization of Core-Shell Microparticles

“…In our previous work, we have reported a systematic study with a reliable analysis tool, which evaluates profile roughness quantitatively, for individual core-shell microparticles using electron microscopy (EM) images of both types, Scanning Electron Microscopy (SEM) and transmission mode SEM (or TSEM) [5,6]. The SEM images contain two-dimensional (2D) information, therefore, provide profile roughness data only from the projection in the horizontal plane (in other words, from the "belly") of a spherical particle.…”

“…Three types of home-made particles having various roughness values were investigated in this work [5,6]: i) bare polystyrene (PS) particles, ii) PS particles decorated with a first magnetic iron oxide (Fe 3 O 4 ) nanoparticle shell forming CS microbeads, and iii) PS/Fe 3 O 4 particles closed with a second silica (SiO 2 ) shell forming core-shell-shell (CSS) microbeads. The most suitable sample preparation procedure prior to microscopy and analysis was considered as follows: the particles have been suspended in ethanol with ultrasonication for 5 min and samples for analysis have been prepared by drop-casting on conventional carbon TEM grids.…”