Advancements in 3D printing of membranes

Additive manufacturing or its more conventional name 3D Printing is a relatively new but increasingly more popular processing method for generating complex structures and is still finding its way into modern industry[1,2]. Thanks to its unprecedented control over processing geometry and resolution, this method is considered highly viable for the membrane industry [3]. However, due to the limitations in the resolution or the processing speed of conventional 3D printing, membranes have been unable to be directly printed and most efforts have been made mostly within space technology or assisting conventional membrane manufacturing[4]. These problems have been largely mitigated by porous printing with SLA (stereolithography) which has pushed the pore-size sub 100nm to about 46nm within the UF membrane sector while retaining the possibility of advanced geometries. Porous printing has opened up innovations within membrane technology such as new membrane materials. With these new materials, we were able to tune the membrane's physiochemical properties. For example, we have shown that we can easily tune the mechanical strength of the membranes as we achieved a gradual increase from a tensile strength of 1.95MPa to 21.20MPa. The working contact angle with a gradual increase 44.25º to 79.51º and achieved as high as a contact angle of 144.2º. Furthermore, the thermal and chemical stability was likewise possible to tune for greater stability as well. Since it also opens up for additive manufacturing and these new physiochemical improvements, new membrane types have been developed for improved membrane desalination, enhanced topology with a 1um resolution, and improved spacer technology for fouling mitigation. A further new SLA-method has shown to be possible to make membranes even out of inorganic materials such as glass. SLA has therefore shown itself as a versatile tool for membrane manufacturing, which has also led to some new separation methods that can rival conventional separation methods.