Regensburg 2022 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster 2

CPP 17.1: Poster

Tuesday, September 6, 2022, 11:00–13:00, P2

Simulation of vapour flow through aperture arrays for quantifying gravimetric mass loss measurements — •Riko Korzetz, Lennart Schulte, and André Beyer — Bielefeld University

Gravimetric mass loss measurements are frequently employed to investigate the permeative behaviour of 2D membranes with respect to vapours of different solvents. Due to constraints in these measurements, insufficient circulation causes the build-up of concentration gradients in the vapour phase, which is known as concentration polarization. This leads to a seemingly non-intuitive permeation behaviour, which complicates the evaluation of the measured data.

Here, we present finite-element simulations that were employed to investigate this effect with respect to different types of membrane supporting apertures and aperture arrays. Both open orifices as well as membranes with different permeance values have been modelled to achieve a quantitative understanding of the relevant effects in mass loss measurements.

We found that for open orifices and apertures with highly permeable membranes, the diffusion from the bulk towards the membrane is the rate-limiting step. This results, for example, in a linear dependence between the permeation rate and the edge length of single open orifices. On the other hand, a dependence on the free-standing area occurs in the case of membranes with a sufficiently low permeance. We devised a phenomenological model to describe the permeation rate in dependence of the membrane permeance as well as support geometry, which allows correction of these effects when evaluating such measured data.