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arXiv · 2109.11116

Formation and morphology of closed and porous films grown from grains seeded on substrates: Two-dimensional simulations

Stoffel D. Janssens·David Vázquez-Cortés·Eliot Fried
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Abstract

Two-dimensional simulations are used to explore topological transitions that occur during the formation of films grown from grains that are seeded on substrates. This is done for a relatively large range of the initial value $Φ_s$ of the grain surface fraction $Φ$. The morphology of porous films is captured at the transition when grains connect to form a one-component network using newly developed raster-free algorithms that combine computational geometry and network theory. Further insight on the morphology of porous films and their suspended counterparts is obtained by studying the pore surface fraction $Φ_p$, the pore over grain ratio, the pore area distribution, and the contribution of pores of certain chosen areas to $Φ_p$. Pinhole survival is evaluated at the transition when film closure occurs using survival function estimates. The morphology of closed films ($Φ= 1$) is also characterized and is quantified by measuring grain areas and perimeters. The majority of investigated quantities are found to depend sensitively on $Φ_s$ and the long-time persistence of pinholes exhibits critical behavior as a function of $Φ_s$. In addition to providing guidelines for designing effective processes for manufacturing thin films and suspended porous films with tailored properties, this work may advance the understanding of continuum percolation theory.

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Stoffel D. Janssens, David Vázquez-Cortés, Eliot Fried. 2022-01-20. Formation and morphology of closed and porous films grown from grains seeded on substrates: Two-dimensional simulations. https://doi.org/10.1016/j.actamat.2021.117555

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