Resistance and Permselectivity of 3D-Printed Micropatterned Anion-Exchange Membranes

Abstract

It has been demonstrated that a micropatterned surface can decrease the resistance of anion exchange membranes (AEMs) and can induce desirable flow properties in devices, such as mixing. Previously, a model that related the resistance of flat and patterned membranes with the same equivalent thickness was proposed, which used the patterned area and thickness ratio of the features to describe the membrane resistance. Here, we explored the validity of the parallel resistance model for a variety of membrane surface designs and area ratios. We demonstrated that the model can predict the resistance of a wide range of patterned AEMs. We showed that the resistance is independent of the spatial ordering of the design by examining random patterns, which is relevant for applications that require, for example, increased turbulent liquid flow in multilayered devices. Some experimental values of resistance obtained for patterned membranes presented deviations from the model. Scanning electron microscopy (SEM) images of the patterned membranes revealed resolution variations and pattern replication errors due to the stereolithographic process. A geometric correction of the target ratios improved the fit of the modelled data to the experimental values, showing that light bleeding during curing was a source of error. Two additional experimental factors were not accounted for in the model: a distinct interface between the bottom and top layer, and overcuring of the bottom layer during successive steps. These sources of error were investigated by examining the resistance of single and double layered membranes, and single layer membranes with different curing times. The differences obtained in the resistances for control samples demonstrated that both the interface and overcuring influence the resistance of the membrane. The results obtained in this study enlighten the discussion relating membrane surface morphology and transport properties, as well as the optimization of 3D printed membranes using a stereolithography process.

Profiled Ion Exchange Membranes: A Comprehensible Review

“…Such an approach of preparing profiled ion exchange membranes is fast, solvent-free and occurs at ambient temperature. In any case, there is still a large margin for future progress in 3D printing of profiled membranes since, due to bleeding during curing, replication errors and a low-profile resolution are currently frequent [60]. Alternatively, the corrugations can be deposited on the top of a commercially-available membrane [53] (Figure 7d).…”

“…Illustrative examples (from References [52,60] of micro-patterned profiled ion exchange membranes prepared by 3D printing, (Reproduced with permission, Copyright 2016 and 2018, respectively, American Chemical Society).…”

Preparation of cation exchange filament for 3D membrane print

“…Nowadays, a wealth of additive technology techniques is known, such as stereo lithography (SLA), FDM, Polyjet, selective laser melting (SLM), selective laser sintering (SLS), direct metal laser sintering (DMLS), 3D printing, laminated object manufacturing (LOM) (Zhang and Jung, 2018). The cost of material from the lowest is generally as follows: LOM < FDM < SLA < SLS < DMLS/SLM (Greguri c, 2019;Tan et al,2019;Capparelli et al, 2018;Tan et al, 2017;Pawlowski et al, 2019). A 3D printing is a relatively new direction for the development of electromembrane processes (Tan et al, 2019;Capparelli et al,2018;Tan et al, 2017;Pawlowski et al, 2019;Low et al, 2017).…”

“…The cost of material from the lowest is generally as follows: LOM < FDM < SLA < SLS < DMLS/SLM (Greguri c, 2019;Tan et al,2019;Capparelli et al, 2018;Tan et al, 2017;Pawlowski et al, 2019). A 3D printing is a relatively new direction for the development of electromembrane processes (Tan et al, 2019;Capparelli et al,2018;Tan et al, 2017;Pawlowski et al, 2019;Low et al, 2017). Tan et al (2019) were engaged in the preparation of electrodes and special vials from polylactic acid (PLA) by FDM method.…”

“…The uncertainty of repeatability of the results on five newly prepared samples ranged from 5% to 18% for different ions (Tan et al, 2019). Seo et al (2016) and Capparelli et al (2018) were dealt with the modification of homogeneous ion exchange membranes (IEMs) prepared by the casting technique. Surface structures on the membranes were formed using lithography and a photoinitiator containing material.…”