Maik Tepper

RWTH Aachen University · DWI - Leibniz-Institute for Interactive Materials

During the first wave of Covid-19 infections in Germany in April 2020, clinics reported a shortage of filtering face masks with aerosol retention > 94% (FFP2 & 3, KN95, N95). Companies all over the world increased their production capacities, but the quality control of once-certified materials and masks came up short. To help identify falsely label...

Membrane geometry evolution boosts membrane applications to become even more sustainable, resource- and energy-efficient. This evolution is crucial as increasingly permeable membrane materials introduce the major drawback of promoting fluid resistance due to boundary layer formation. We present how to break these boundary layers with Helical Ridge...

Composite membranes are highly permeable and used with great success in nanofiltration, reverse osmosis and gas separation. However, the higher the membrane permeability gets, the more pronounced becomes the role of the laminar boundary layer. Common approaches to overcome boundary layer limitation include the use of spacers or inserts, which induc...

Membranes are semi-permeable barriers to control mass transport and enable chemical separation processes on a molecular level. Focus areas of hollow fiber membrane technology include water treatment, food and beverage processing, gas separation and medical applications. Intense membrane research has succeeded in developing better membrane materials...

New membrane geometries have the potential to increase mixing at the feed and permeate side to counteract concentration polarization and fouling. Such membrane geometries can be of very different architecture. Here, we address a new class of hollow fiber membranes having helical ridges. We focus on gas–liquid mass transfer, which is significantly s...

This study tracks the physical aging behavior of coated and uncoated ultra‐thin poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) films on silicon wafers based on the refractive index using ellipsometry. The measured refractive index directly correlates with the free volume and hence the physical aging progression. Plasma‐enhanced chemical vapor deposition...

Turbulence promoters boost the efficiency of membrane applications suffering from mass transfer limitations. To counteract these mass transfer limitations, static mixers were established for flat sheet and tubular membrane geometries. However, the combination of static mixers with hollow fiber membranes has not been possible because of tedious asse...

During the first wave of Covid-19 infections in Germany in April 2020, clinics reported a shortage of filtering face masks with aerosol retention> 94% (FFP2 & 3, KN95, N95). Companies all over the world increased their production capacities, but quality control of once-certified materials and masks came up short. To help identify falsely labeled ma...

de Mit dem direkten Spinnverfahren können Komposit‐Hohlfasermembranen in einem einstufigen Prozess hergestellt werden. Dabei wird die klassische Faserbildung mit einer Grenzflächenpolymerisation auf der Lumenseite der Hohlfaser überlagert. Für die Herstellung von sinusförmigen Hohlfasermembranen wird im herkömmlichen Nassspinnprozess zusätzlich die...

Geometrically structured flow channels induce secondary flows and vortices enhancing mass and heat transport rates. In particular, these vortices may reduce concentration polarization and subsequent fouling in membrane transport processes. In this work we present a new method of producing hollow fiber membranes with a sinusoidal change in diameter...