Copolymers with a polyvinyl block and

A) Synthesis of Copolymers with a Polyvinyl Block and a Hydrophobic... 

Fig. 37. Example of an electron micrograph of copolymers with a polyvinyl block and a polypeptide block. Copolymer polybutadiene-poly(benzyl-L-glutamate) BG.530 containing 33% polypeptide with polydiene chains have been stained with osmium tetroxide...

In biological membranes, integral proteins are amphipatic molecules their hydro-phobic moiety is embedded in the lipid bilayer and their hydrophilic moiety protrudes from the surface of the membrane279. So, it was interesting to prepare polymeric models of such amphipatic proteins. For that purpose, two new classes of block copolymers have been synthetized in Orleans, namely copolymers with a polyvinyl block and a polypeptide block and copolymers with a saccharide and a peptide block. We shall give some information concerning the preparation of these copolymers and then describe their structure. 

Fig. 38. Example of variation of the geometrical parameters of the lamellar structure of copolymers with a polyvinyl block and a hydrophobic polypeptide block. Copolymer BG.530 in dioxane solution22 ...

Copolymers with a polyvinyl block and a polypeptide block... 

The second class of mesomorphic copolymers that we have synthesized and studied consists of copolymers with a polyvinyl block and a polypeptide block. In these copolymers the first block is a polystyrene or a polybutadiene block and the second block is a hydrophobic or a hydrophilic polypeptide block. 

For all copolymers studied (copolymers containing between 18 % and 83 % of polypeptide] the liquid crystalline structures are always lamellar and are very similar to the structure of saccharide-peptide block copolymers. In the lamellar structure of copolymers with a polyvinyl block and a hydrophobic polypeptide block, each sheet of thickness d results from the superposition of two layers one of thickness d/ formed by the polyvinyl chains in a more or less random coil conformation, the other of thickness dg formed by the polypeptide chains, in an a helix conformation, arranged in an hexagonal array, and generally folded ( 7, 8]. ... 

Copolymers with a polyvinyl block and two polypeptide blocks may be obtained by two different ways differing by the type of polymerization used in the synthesis of the polyvinyl block. 

The synthesis of AB and ABA block copolymers with a polyvinyl and one or two polypeptide blocks is performed in 3 steps. At first the polyvinyl block is obtained by anionic or radical polymeriza-... 

Fig. 1. Schematic representation of the lamellar structure of AB copolymers with a polyvinyl and a polypeptide block. ...

The principal factors governing the folding of the polypeptide chains in AB copolymers with a polyvinyl and a polypeptide block and in ABA copolymers with a polyvinyl and 2 polypeptide blocks are the solvent concentration, the molecular weight of the blocks and the nature of the blocks. 

A. Douy and B. Gallot, Block copolymers with a polyvinyl and a... 

The main results of this miero-mechanical model in the quasi-static regime have been compared with experimental results obtained by placing polystyrene (PS)-polyvinyl pyridine (PVP) diblock copolymers with a short PVP block between PS and PVP homopolymers. The fracture toughness was found to increase linearly with E from that of the bare PS/PVP interface, while the slope of the line increased with the degree of polymerization of the block being pulled out. If the data for the different copolymers were plotted as AG vs. (where... 

Block copolymers with a hydrophobic polyvinyl block and a hydrophobic polypeptide block (BG, SG, SC, SL, BCK and SCK copolymers) exhibit well organized meso-phases in dioxane, 1,2-dichloroethane, 2,3-dichloro 1-propene, etc., solutions. These mesophases are observed for solvent concentrations smaller than about 60% and for dry samples obtained by evaporation of the solvent at a slow rate. 

Copolymers with a hydrophobic polyvinyl block and a hydrophilic polypeptide block like polybutadiene-poly(L-lysine) (BK), polystyrene-poly(L-lysine) (SK),poly-butadiene-poly(L-glutamic acid) (BE), and polystyrene-poly(L-glutamic acid) (SE) are obtained by action of HC1 and HBr on copolymers BCK, SCK, BG, and SG, respectively23. ... 

The behaviour of copolymers SK is typical for the behaviour of copolymers with a hydrophobic polyvinyl block and a hydrophilic polypeptide block. They exhibit mesophases in water for water concentration ranging from 0 to 50% and the structure of the mesophases is lamellar23. The special feature of this lamellar structure consists in the conformation of the polylysine chains which are roughly to 15% in a 0-chain conformation, to 35% in an a-helix conformation and to 50% in a coiled conformation23, so that the hydrophilic block of such amphipatic copolymers has the same type of conformation as the hydrophilic part of the membrane proteins. 

The lamellar structure of saccharide-peptide block copolymers presents many analogies with the structure of copolymers with a hydrophobic polyvinyl block and a hydrophobic polypeptide block and exhibits a similar behaviour as a function of the solvent concentration. When the solvent concentration increases the total thickness of a sheet and the thickness of the carbohydrate layer both increase while the thickness of the polypeptide layer remains nearly constant284. ... 

Teyssie and coworkers have studied the surface, interfacial, and emulsifying properties of AB2 stars where A is a polydiene or polyvinyl block and B polyethylene oxide)(PEO) [297,298]. The miktoarm stars were shown to be better emulsifying agents for water-organic solvent mixtures than linear block copolymers. Saturation of the interface is reached more quickly with the miktoarm stars. Their results are in agreement with the results of Xie and Xia on PS2PE02 stars [228]. 

Billot, J.P., Douy, A., and Gallot, B. (1976) Synthesis and structural study of block copolymers with a hydrophobic polyvinyl block and a hydrophilic polypeptide block Copolymers polystyrene/poly(L-lysine) and polybutadiene/ poly(L-lysine). Makromolekulare Chemie-Macromolecular Chemistry and Physics, 111, 1889-1893. 

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