3D-printed rotating spinnerets create membranes with a twist

TL;DR

This paper introduces a novel 3D-printing method for creating twisted and helical bore channels in membranes, potentially improving mass transport and reducing fouling in applications like filtration and gas separation.

Contribution

The authors develop a systematic methodology using 3D-printed, rotating spinnerets to fabricate membranes with complex twisted geometries, advancing membrane design capabilities.

Findings

Twisted bore channels can enhance mass transfer efficiency.

Rotating spinnerets enable fabrication of complex helical membrane geometries.

Membranes produced with this method show potential for improved performance.

Abstract

Round hollow fiber membranes are long-established in applications such as gas separation, ultrafiltration and blood dialysis. Yet, it is well known that geometrical topologies can introduce secondary ow patterns counteracting mass transport limitations, stemming from diffusion resistances and fouling. We present a new systematic method- ology to fabricate novel membrane architectures. We use the freedom of design by 3D-printing spinnerets, having multiple bore channels of any geometry. First, such spinnerets are stationary to fabricate straight bore channels inside a monolithic membrane. Second, in an even more complex design, a new mechanical system enables rotating the spinneret. Such rotating multibore spinnerets enable (A) the preparation of twisted channels inside a porous monolithic membrane as well as (B) a helical twist of the outside geometry. The spun material systems comprise classical polymer solutions as well as metal-polymer slurries resulting in solid porous metallic monolithic membrane after thermal post-processing. It is known that twisted spiral-type bore channel geometries are potentially superior over straight channels with respect to mass and heat polarization phenomena, however their fabrication was cumber- some in the past. Now, the described methodology enables membrane fabrication to tailor the membrane geometry to the needs of the membrane process.