Block Copolymer Membranes-Progress and Challenges.

Block copolymers are capable of providing more than one advantageous property due to their selected repeating units, which make them an outstanding candidate for polymer-based membranes [...

Spraying of Ultrathin Isoporous Block Copolymer Membranes-A Story about Challenges and Limitations.

Isoporous membranes can be prepared by a combination of self-assembly of amphiphilic block copolymers and the non-solvent induced phase separation process. As the general doctor-blade technique suffers from high consumption of expensive block copolymer, other methods to reduce its concentration in the casting solution are sought after. Decreasing the block copolymer concentration during membrane casting and applying the block copolymer solution on a support membrane to obtain ultrathin isoporous membrane layers with e.

A Combined Ultrafiltration/Diafiltration Step Facilitates the Purification of Cyanovirin-N From Transgenic Tobacco Extracts.

The production of biopharmaceutical proteins in plants offers many advantages over traditional expression platforms, including improved safety, greater scalability and lower upstream production costs. However, most products are retained within plant cells or the apoplastic space instead of being secreted into a liquid medium, so downstream processing necessarily involves tissue and cell disruption followed by the removal of abundant particles and host cell proteins (HCPs). We investigated whether ultrafiltration/diafiltration (UF/DF) can simplify the purification of the model recombinant protein cyanovirin-N (CVN), an ~ 11 kDa HIV-neutralizing lectin, from tobacco extracts prior to chromatography.

Colour-Value Based Method for Polydopamine Coating-Stability Characterization on Polyethersulfone Membranes.

Porous polyethersulfone membranes as used in oenology were investigated in order to evaluate temperature-dependent permeances in a temperature range from 10 to 35 °C. A temperature correction factor was determined for this type of membrane to get accurate and comparable results for further developments. Moreover, the membranes were modified with a bio-inspired polydopamine coating in order to reduce fouling.

Perfluorinated Compounds as Test Media for Porous Membranes.

We suggest a failure-free method of porous membranes characterization that gives the researcher the opportunity to compare and characterize properties of any porous membrane. This proposal is supported by an investigation of eight membranes made of different organic and inorganic materials, with nine different perfluorinated compounds. It was found that aromatic compounds, perfluorobenzene, and perfluorotoluene, used in the current study show properties different from other perfluorinated aliphatics.

Thin Isoporous Block Copolymer Membranes: It Is All about the Process.

The combination of the self-assembly of amphiphilic block copolymers and the nonsolvent induced phase inversion process offers an efficient way to isoporous integral-asymmetric membranes. In this context we report fast, easily upscalable and material reducing ways to thin self-assembled membranes. Therefore, we succeeded to implement a spray or dip coating step into the membrane formation process of different diblock copolymers like polystyrene-block-poly(4-vinylpyridine), poly(α-methylstyrene)-bock-poly(4-vinylpyridine), and polystyrene-block-poly(iso-propylglycidyl methacrylate).

Postmodification of PS-b-P4VP diblock copolymer membranes by ARGET ATRP.

The surfaces of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer membranes were modified in order to obtain polymer brushes by using surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Isoporous membranes were prepared by the combination of self-assembly of PS-b-P4VP diblock copolymers and the nonsolvent induced phase separation process, also known as "phase inversion". In order to allow further functionalization, the membranes were modified with an ATRP initiator, 2-bromoisobutyryl bromide (BIBB).

Carbohydrates as additives for the formation of isoporous PS-b-P4VP diblock copolymer membranes.

Highly porous polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer membranes are prepared using carbohydrates as additives. Therefore α-cyclodextrine, α-(D)-glucose, and saccharose (cane sugar) are tested for the membrane formation of three different PS-b-P4VP polymers. The addition of the carbohydrates leads to an increasing viscosity of the membrane solutions due to hydrogen bonding between hydroxyl groups of the carbohydrates and pyridine units of the block copolymer.