Untitled

Abstract

Crack patterns of 53 nm and 103 nm thick silicon oxide coatings on poly(ethylene terephthalate) films are analyzed under equibiaxial stress loading, by means of a bulging cell mounted under an optical microscope with stepwise pressurization of film specimens. The biaxial stress and strain are modeled from classical elastic membrane equations, and an excellent agreement is obtained with a finite element method. In the large pressure range, the derivation of the biaxial strain from force equilibrium considerations are found to reproduce accurately the measured data up to 25% strain. The examination of the fragmentation process of the coating under increasing pressure levels reveals that the crack onset strain of the oxide coating is similar to that measured under uniaxial tension. The fragmentation of the coating under biaxial tension is also characterized by complex dynamic phenomena which image the peculiarities of the stress field, resulting in considerable broadening of the fragment size distribution. The evolution of the average fragment area as a function of biaxial stress in the early stages of the fragmentation process is analyzed using Weibull statistics to describe the coating strength.

Mechanical Control of Surface Adsorption by Nanoscale Cracking

“…These peaks are consistent with the presence of both PDMS and PEI. Next, adsorbing a monolayer of negatively charged silica nanoparticles onto the positively charged PEI caused the mass/charge peak at 40 to disappear entirely ( Figure 1 d), which is consistent with a surface containing [ 28 ] Si but no PEI. Finally, upon stretching the PDMS (Δ L / L = 45% ) , (Figure 1 f).…”

“…Similar variability was observed when thin coatings were cracked using uniaxial strain. [26][27][28] Fourth, the crack should not only allow a material to deposit but also impart some degree of selectivity. Ideally, the crack should control the size, shape, and crystallographic orientation of the material that deposits.…”

Room-Temperature, Solution-Processed SiOx via Photochemistry Approach for Highly Flexible Resistive Switching Memory

“…46 Generally, cracks always result from releasing internal stress and the mismatch of thermal expansion coefficients between layers can lead to the generation of biaxial interfacial stress during hightemperature process, which brings about the device failure by delamination. 47 The SiO x layer prepared here at room temperature not only avoids the interface mismatch but also guarantees a low internal stress inherently due to its mass increment process and relatively low modulus (Figure S13) compared with the sol−gel process. 15 Additionally, the recently reported typical flexible performance of SiO x -based RRAMs via the PVD method is also listed in Table 1.…”

P‐106: Real‐Time Inspection of a Moisture Barrier Film Buried by a Protective Layer for Flexible Displays

“…This stress-induced cracking is critical because it may lead to device degradation. There are several different approaches for mechanical testing of thin films on flexible substrates, such as tensile test [5,6], bulge test [7], and bending test [8,9]. In-situ characterization of the film cracking is challenging.…”