Membranes block polymers

Edmondson, C. A., Eontanella, J. J., Chung, S. H., Greenbaum, S. G. and Wnek, G. E. 2001. Complex impedance studies of S-SEBS block polymer proton-conducting membranes. Electrochimica Acta 46 1623-1628. 

A relatively new development which promises to gain in importance in the future is the modification of asphalt by butadiene-styrene block polymers.44 The block polymers help reduce the low temperature brittleness and impart resistance to flow at elevated temperatures. Applications in mastics, automobile body undercoatings and waterproofing materials such as high quality roofing membranes are envisaged. 

Keywords Amphiphilic block copolymers, Membranes, Nanoreactors, Polymer-somes, Self-assembly, Stimuli-responsive vesicles... 

Often preventive measures may be taken to avoid fouling the membrane. Prefilters or screens can be used to remove large particles which block thin channels or accumulate in stagnant areas of the module. High cross-flow velocities tend to sweep deposits away. Low pressures avoid compaction of gels on the membrane. Some polymers have a higher susceptibility to fouling and chemical modification of the membrane surface can have a profound effect on the propensity to foul. 

The polymer efficiently permeabilises anionic vesicles with compositions which mimic those of bacterial membranes. The polymer binds to anionic phospholipid vesicles but not zwitterionic vesicles, which causes phase separation in anionic phospholipid mixtures, clustering the negative charge. The polymer permeabilises the outer membrane of Escherichia coli ML-35p in a biphasic manner low polymer concentrations permeabilise the inner membrane of Escherichia coli ML-35p, whereas high concentrations of the polymer can block the active transport of or onitrophenyl-P-n-galactoside in wild-type Escherichia coli K12 [17]. 

In order to design new membrane materials with superior separation performance, low cost and feasible for massive production, the old work of Kulprathipanja can be considered as a proper tool [23]. He dispersed polyethylene glycol (PEG) in PDMS and improved the CO2 penneability. A similar idea led us to modify or blend existing commercial block polymers containing ethylene oxide (EO) units with poly(ethylene) glycol [24] and thus by a blending process it was possible to produce high C02-selective membrane materials with improved permeability. 

Zhang X, Tanner P, Graff A, Palivan CG, Meier W. Mimicking the cell membrane with block copolymer membranes. J Polym Sci 2012 50(12) 2293—318. 

Hydrocarbon Membranes for Polymer Electrolyte Fuel Cells, Fig, 1 BPSH/BPS block copolymer (A andB are the numbers of repeat unit of hydrophilic and hydrophobic blocks, respectively, n is the degree of polymerization)... 

Hydrocarbon Membranes for Polymer Electrolyte Fuel Cells, Fig. 3 Humidity dependence of the proton conductivity of SPESK block copolymer membrane (lEC = 1.62 meq/g) at 80 °C and 110 °C... 

Asano N, Miyatake K, Watanabe M (2006) Sulfonated block polyimide copolymers as a proton-conductive membrane. J Polym Sci, A Polym Chem 44 2744-2748... 

Dorin Rachel Mika, Phillip William, Sai Hiroaki, Werner Jorg, Elimelech Menachem, and Wiesner Ulrich. Designing block copolymer architectures for targeted membrane performance. Polymer. 55 no. 1 (2014) 347-353. 

Potentiometry HPO42- 31 1 Polystyrene-polybutadienene block polymer membrane with the phosphate ionophore, 3-allyl-l,5,8-triazacyclodecane-2,4-dione operational life of 40 days [114]... 

Potentiometric methods for the detection of phosphate based on polymer wire coated or membrane ion selective electrodes have until recently suffered from poor selectivity, sensitivity, and lifetime, and have been unsuitable for most water analysis applications (Table 8.2) [111,112]. Recent developments in membrane formulation involving PVC containing vanadyl salophen [113] or polystyrene-polybutadienene block polymers with the phosphate ionophore, 3-allyl-l,5,8-triazacyclodecane-2,4-dione [114], show much improved membrane lifetime, sensitivity, and selectivity for phosphate, and offer considerable promise for future water-monitoring applications. 

Malinova V, Belegrinou S, de Bmyn Ouboter D, Meier WP (2010) Biomimetic block copolymer membranes. Adv Polym Sci 224 113-165... 

The pore size distribution of the caibonized membranes for polymer concentrations of 12, 10 and 8 wt% are shown in Fig. 8.41a-c, respectively. The mean pore size of the membranes was in the microfiltration range, and the pore size increases with the polymer concentration. These results are in agreement with the fiber diameter of the membranes, which were noted to increase with the polymer concentration. A monodispersed pore size distribution was observed for 10 and 12 wt% polymer concentration, whereas a bidispersed pore size distribution was observed for the 8 wt% polymer concentration. It is hypothesized that this is due to the presence of beads in the 8 wt% polymer concentration, hence there are pores that are blocked by the beads, which results in a bidispersion of the pore size distribution. 

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