Artificial lung (AL) membranes are used for blood oxygenation for patients undergoing open-heart surgery or acute lung failures. Current AL technology employs polypropylene and polymethylpentene membranes. Although effective, these membranes suffer from low biocompatibility, leading to undesired blood coagulation and hemolysis over a long term. In this work, we propose a new generation of AL membranes based on amphiphobic fluoropolymers. We employed poly­(vinylidene-co-hexafluoropropylene), or PVDF-co-HFP, to fabricate macrovoid-free membranes with an optimal pore size range of 30–50 nm. The phase inversion behavior of PVDF-co-HFP was investigated in detail for structural optimization. To improve the wetting stability of the membranes, the fabricated membranes were coated using Hyflon AD60X, a type of fluoropolymer with an extremely low surface energy. Hyflon-coated materials displayed very low protein adsorption and a high contact angle for both water and blood. In the hydrophobic spectrum, the data showed an inverse relationship between the surface free energy and protein adsorption, suggesting an appropriate direction with respect to biocompatibility for AL research. The blood oxygenation performance was assessed using animal sheep blood, and the fabricated fluoropolymer membranes showed competitive performance to that of commercial polyolefin membranes without any detectable hemolysis. The data also confirmed that the bottleneck in the blood oxygenation performance was not the membrane permeance but rather the rate of mass transfer in the blood phase, highlighting the importance of efficient module design.

The recent outbreak of the COVID-19 pandemic in 2020 reasserted the necessity of artificial lung membrane technology to treat patients with acute lung failure. In addition, the aging world population inevitably leads to higher demand for better artificial organ (AO) devices. Membrane technology is the central component in many of the AO devices including lung, kidney, liver and pancreas. Although AO technology has improved significantly in the past few decades, the quality of life of organ failure patients is still poor and the technology must be improved further. Most of the current AO literature focuses on the treatment and the clinical use of AO, while the research on the membrane development aspect of AO is relatively scarce. One of the speculated reasons is the wide interdisciplinary spectrum of AO technology, ranging from biotechnology to polymer chemistry and process engineering. In this review, in order to facilitate the membrane aspects of the AO research, the roles of membrane technology in the AO devices, along with the current challenges, are summarized. This review shows that there is a clear need for better membranes in terms of biocompatibility, permselectivity, module design, and process configuration.

Membrane technology has become an indispensable part of our daily lives. The rapid growth of membrane technology has been breeding an unavoidable yet critical challengethe unsustainable disposal of used membranes. Commercial polymer membranes are fabricated from fossil-based monomers and polymers that are not biodegradable. Hence, there is an urgent need to develop membranes that are sustainable from cradle to grave, i.e., both bioderived and biodegradable. Cellulose is one of the most abundant biopolymers that are biodegradable upon disposal. However, it is only soluble in a handful of solvents, limiting its fabrication into membranes at an industrial scale. To circumvent this bottleneck, in this work, we propose a sustainable and scalable method to fabricate cellulose membranes from cellulose acetate with a sacrificial acetate group. The proposed method allows cellulose membrane fabrication utilizing green solvents, and the fabrication procedure is sustainable with minimal solvent consumption. One of the most appealing applications of cellulose membranes is organic solvent nanofiltration (OSN). It is an emerging technology to separate solutes in nanoprecision in harsh organic solvents, requiring solvent-stable materials. Surprisingly, the cellulose membranes exhibited unique transport behaviors, with solute rejection ranging from 100 to −100% depending on the solvent medium. Such trends were not previously observed in the OSN literature, and the underlying mechanism was thoroughly investigated. Importantly, the membranes were completely biodegradable in a carbon-neutral manner upon disposal. The life cycle of cellulose membranes was compared with that of conventional OSN membranes in a qualitative and comparative study. The proposed methodology can be applied to substitute fossil-based polymers in all aspects of membrane technology, and it has the potential to become a sustainable fabrication platform for membrane materials.

Organic solvent nanofiltration (OSN) has been considered as one of the key technologies to improve the sustainability of separation processes. Recently, apart from enhancing the membrane performance, greener fabricate on of OSN membranes has been set as a strategic objective. Considerable efforts have been made aiming to improve the sustainability in membrane fabrication, such as replacing membrane materials with biodegradable alternatives, substituting toxic solvents with greener solvents, and minimizing waste generation with material recycling. In addition, new promising fabrication and post-modification methods of solvent-stable membranes have been developed exploiting the concept of interpenetrating polymer networks, spray coating, and facile interfacial polymerization. This review compiles the recent progress and advances for sustainable fabrication in the field of polymeric OSN membranes.

Thin film composite (TFC) membranes is the dominant type of desalination in the field of membrane technology. Most of the TFC membranes are fabricated via interfacial polymerization (IP) technique. The ingenious chemistry of reacting acyl chlorides with diamines at the interface between two immiscible phases was first suggested by Cadotte back in the 1980s, and is still the main chemistry employed now. Researchers have made incremental improvements by incorporating various organic and inorganic additives. However, most of the TFC membrane literature are focused on improving the water desalination performance. Recently, the application spectrum of membrane technology has been expanding from the aqueous environment to harsh solvent environments, now commonly known as Organic Solvent Nanofiltration (OSN) technology. In this work, some of the main additives widely used in the desalination TFC membranes were applied to OSN TFC membranes. It was found that tributyl phosphate (TBP) can improve the solubility of diamine monomer in the organic phase, and sodium dodecyl sulfate (SDS) surfactant can effectively stabilize the IP reaction interface. Employing both TBP and SDS exhibited synergistic effect that improved the membrane permeance and rejection in solvent environments.