Abstract:Closed cell polymer foam skin thickness can be assessed by taking backscatter electron (BSE) images in a scanning electron microscope (SEM) at a series of accelerating voltages. Under a given set of experimental conditions, the electron beam mostly passes through thin polymer skin cell walls. That cell appears dark compared to adjacent thicker-skinned cells. Higher accelerating voltages lead to a thicker skin being penetrated. Monte Carlo modeling of beam-sample interactions indicates that at 5 keV, skin less … Show more
“…Monte Carlo simulation for electron microscope analysis has been reported in many publications. , It is a useful tool for researchers and operators to understand beam–sample interactions in order to choose favorable experimental conditions for lab experiment design. Figure a shows the simulation result of different accelerating voltage beams interacting with nickel.…”
Nickel manganese cobalt oxide (NMC) is a high energy capacity cathode material that attracts the interest of many research groups. Coating a protection layer on the NMC surface is one approach to improve its cycling and safety performance. However, there is no standard and consistent way to characterize the coating performance (thickness) of this protection layer, especially due to the nanoscale of primary particle and spherical morphology of the secondary particle. In this paper, a novel empirical method based on energy dispersive X-ray spectroscopy (EDX) analysis at low accelerating voltage is proposed to evaluate the protection layer thickness on the scale of tens of nanometers. The layer thickness is characterized by measuring the intensity decrease of a substrate element due to absorption by overlying coating layers. An internal standard coating (metal layer) is applied to mimic the morphology influence and improve the accuracy of thickness quantitation. For the model sample evaluation, carbon layer coatings of 1 to 10 nm thickness were successfully quantified by this method.
“…Monte Carlo simulation for electron microscope analysis has been reported in many publications. , It is a useful tool for researchers and operators to understand beam–sample interactions in order to choose favorable experimental conditions for lab experiment design. Figure a shows the simulation result of different accelerating voltage beams interacting with nickel.…”
Nickel manganese cobalt oxide (NMC) is a high energy capacity cathode material that attracts the interest of many research groups. Coating a protection layer on the NMC surface is one approach to improve its cycling and safety performance. However, there is no standard and consistent way to characterize the coating performance (thickness) of this protection layer, especially due to the nanoscale of primary particle and spherical morphology of the secondary particle. In this paper, a novel empirical method based on energy dispersive X-ray spectroscopy (EDX) analysis at low accelerating voltage is proposed to evaluate the protection layer thickness on the scale of tens of nanometers. The layer thickness is characterized by measuring the intensity decrease of a substrate element due to absorption by overlying coating layers. An internal standard coating (metal layer) is applied to mimic the morphology influence and improve the accuracy of thickness quantitation. For the model sample evaluation, carbon layer coatings of 1 to 10 nm thickness were successfully quantified by this method.
“…BSEs have a distribution of energies and the sensitivity of BSE detectors is a complex function of electron energy (Radzimski & Russ, 1995). However, work by Todd & Kuznetsova (2011) showed that the backscatter coefficient is an acceptable proxy for the signal from typical solid-state BSE detectors in SEMs. Figure 6 Modeled backscattered electron coefficient as a function of latex layer thickness and accelerating voltage.…”
Section: Resultsmentioning
confidence: 99%
“…Although many authors have used characteristic X-ray attenuation to quantitatively measure coating thicknesses (i.e., Pouchou & Pichoir, 1990; Pouchou, 1993), there are few literature examples exploiting BSE images collected at a range of accelerating voltages to quantitatively characterize layer thickness information in this manner (Todd & Kuznetsova, 2011). Regardless of the quantitative calibration of image brightness to exact latex thickness, qualitative comparison of latex coverage by characterizing bright/dark distribution in BSE images within one sample or between different samples is robust and easy to apply.…”
Polyvinylidene chloride (PVDC) co-polymer resins are commonly formulated with a variety of solid additives for the purpose of processing or stabilization. A homogeneous distribution of these additives during handling and processing is important. The Dow Chemical Company developed a process to incorporate solid materials in latex form onto PVDC resin bead surfaces using a coagulation process. In this context, we present a method to characterize the distribution and thickness of these latex coatings. The difference in backscattered electron signal from the higher mean atomic number PVDC core and lower atomic number latex coating in conjunction with scanning electron microscopy (SEM) imaging using a range of accelerating voltages was used to characterize latex thickness and distribution across large numbers of beads quickly and easily. Monte Carlo simulations were used to quantitatively estimate latex thickness as a function of brightness in backscatter electron images. This thickness calibration was validated by cross-sectioning using a focused ion-beam SEM. Thicknesses from 100 nm up to about 1.3 µm can be determined using this method.
“…The number of pores depends on the type of spongy material. There are low, medium and high porosity materials (Liu et al, 2014;Todd and Kuznetsova, 2011). It is assumed that the first two types have a closed pore structure resembling dense crisscrossed connections.…”
A b s t r a c t. Based on a literature review, the development and importance of foamed bioplastics in the context of conventional materials has been discussed in the paper. Raw materials, technological aspects, types of products (including a new generation of bioplastics), their advantages and disadvantages as well as user expectations are presented. Despite considerable progress, especially in the formulation of new raw material compositions, there is still a need to continue research work on the application of different techniques in the production of biodegradable porous packaging materials. It still remains the current primary goal -to produce products with physical characteristics that are comparable with those of petroleum based plastic.K e y w o r d s: physical properties, foams, porous materials, bioplastics, starch-based packaging materials
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