Sub-3-Nanometer Domain Spacings of Ultrahigh-χ Multiblock Copolymers with Pendant Ionic Groups

ACS Nano ◽  
2021 ◽  
Author(s):  
Jinseok Park ◽  
Anne Staiger ◽  
Stefan Mecking ◽  
Karen I. Winey
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.


1997 ◽  
Vol 7 (10) ◽  
pp. 1489-1497 ◽  
Author(s):  
A. N. Semenov

2018 ◽  
Vol 20 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Xavier Santarelli ◽  
Charlotte Cabanne

Mixed mode chromatography offers a diversity of ligands, each providing a new selectivity. This allows the design of novel purification processes with reduced column steps. Structure of ligands is based on both hydrophobic and ionic groups. Thanks to its salt tolerance, crude extracts or post-IEX samples can be loaded directly without conditioning. The selectivity could be enhanced by modulating elution parameters or by using additives. More importantly, mixed mode chromatography could be as effective as affinity chromatography for mAb purification processes. Mixed mode chromatography opens the way to short and economical processes.


2021 ◽  
pp. 2100003
Author(s):  
Yousef Mohammadi ◽  
Mohammad Reza Saeb ◽  
Alexander Penlidis ◽  
Esmaiel Jabbari ◽  
Florian J. Stadler ◽  
...  

2014 ◽  
Vol 3 (5) ◽  
pp. 453-457 ◽  
Author(s):  
Catherine N. Walker ◽  
Joel M. Sarapas ◽  
Vanessa Kung ◽  
Ashley L. Hall ◽  
Gregory N. Tew

2011 ◽  
Vol 53 (12) ◽  
pp. 1207-1216 ◽  
Author(s):  
A. A. Gavrilov ◽  
D. V. Guseva ◽  
Ya. V. Kudryavtsev ◽  
P. G. Khalatur ◽  
A. V. Chertovich

2016 ◽  
Author(s):  
T. Kosaka ◽  
Y. Kawaguchi ◽  
T. Himi ◽  
T. Shimizu ◽  
K. Hirahara ◽  
...  

1956 ◽  
Vol 145 (921) ◽  
pp. 554-563 ◽  

The proteins concerned have been spread at the air/water interface on a substrate at physio­logical ionic strengths. Spread protein A has been ‘injected’ with dissolved protein B , and the increase in pressure observed has been attributed to adsorption. This adsorption has been found to depend on the area per molecule of the spread protein, reaching a maximum value at an intermediate area value. It is postulated that adsorption occurs by hydrogen bonds between B and A , and that at a certain stage of compression the bonding groups in A turn so as to form hydrogen bonds within the monolayer, a theory which accords with compressibility and viscosity data on the monolayers. The rate of increase of pressure depends markedly on ionic strength suggesting that the rate of adsorption is influenced by the interaction of ionic groups in A and B . No evidence was obtained for a surface clotting reaction or specific interaction between fibrinogen and thrombin, whichever protein formed the monolayer, suggesting that the specific interaction involves at least two groups in each protein held at a critical spacing.


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