Wetting-Induced Polyelectrolyte Pore Bridging

Membranes, vol. 11, pp. 671

Abstract

Active layers of ion separation membranes often consist of charged layers that retain ions based on electrostatic repulsion. Conventional fabrication of these layers, such as polyelectrolyte deposition, can in some cases lead to excess coating to prevent defects in the active layer. This excess deposition increases the overall membrane transport resistance. The study at hand presents a manufacturing procedure for controlled polyelectrolyte complexation in and on porous supports by support wetting control. Pre-wetting of the microfiltration membrane support, or even supports with larger pore sizes, leads to ternary phase boundaries of the support, the coating solution, and the pre-wetting agent. At these phase boundaries, polyelectrolytes can be complexated to form partially freestanding selective structures bridging the pores. This polyelectrolyte complex formation control allows the production of membranes with evenly distributed polyelectrolyte layers, providing (1) fewer coating steps needed for defect-free active layers, (2) larger support diameters that can be bridged, and (3) a precise position control of the formed polyelectrolyte multilayers. We further analyze the formed structures regarding their position, composition, and diffusion dialysis performance.

Authors 5

1. Anna Maria Kalde Aachen DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials

   Affiliation as printed

   DWI-Leibniz—Institute for Interactive Materials, Forckenbeckstrasse 50, 52074 Aachen, Germany

2. Johannes Kamp Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering, RWTH Aachen University, Forckenbeckstrasse 51, 52074 Aachen, Germany

3. Elizaveta Evdochenko Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering, RWTH Aachen University, Forckenbeckstrasse 51, 52074 Aachen, Germany

4. John Linkhorst Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering, RWTH Aachen University, Forckenbeckstrasse 51, 52074 Aachen, Germany

5. Matthias Weßling corresponding Aachen Chemical Process Engineering DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering, RWTH Aachen University, Forckenbeckstrasse 51, 52074 Aachen, Germany

   DWI-Leibniz—Institute for Interactive Materials, Forckenbeckstrasse 50, 52074 Aachen, Germany