Side-chain copolymers

So far, there have been only few reports about the synthesis of amphipolar polymer brushes, i.e. with amphiphilic block copolymer side chains. Gna-nou et al. [115] first reported the ROMP of norbornenoyl-endfunctionalized polystyrene-f -poly(ethylene oxide) macromonomers. Due to the low degree of polymerization, the polymacromonomer adopted a star-like rather than a cylindrical shape. Schmidt et al. [123] synthesized amphipolar cylindrical brushes with poly(2-vinylpyridine)-block-polystyrene side chains via radical polymerization of the corresponding block macromonomer. A similar polymer brush with poly(a-methylstyrene)-Wocfc-poly(2-vinylpyridine) side chains was also synthesized by Ishizu et al. via radical polymerization [124]. Using the grafting from approach, Muller et al. [121, 125] synthesized... 

Comb polymer with a poly(methacrylic acid) backbone and polyacrylonitrile side chains Comb polymer with unspecified backbone composition and statistical ethylene/vinyl chloride copolymer side chains... 

Hydrogel photoresponsiveness was obtained in a copolymer of acrylic acid and N-dodecylacrylamide in the presence of a-CD and 4,4 -azodibenzoic acid. The gel, formed by hydrophobic association of the copolymer side chains, turned to sol on addition of a-CD because of the inclusion of the hydrophobic chains. In the presence of 4,4 -azodibenzoic acid, as competitive guest for a-CD, the sol-gel transition could be reversibly controlled via the trans-cis photoisomerization of the azocompound. ... 

Core-Shell Diblock Copolymer Side Chains... 

Scheme 10.9 Synthetic procedure of amphiphilic core-shell cylindrical brushes with PS-b-PAA diblock copolymer side chains [100]. (Reproduced with permission of the American Chemical Society.)...

The grafting from approach allows one to manipulate the chemical composition of the side chains. In addition to homopolymer bmshes, one can prepare molecular brushes with both random and coaxial or adjacent block copolymer side chains. 

H) Core-shell diblock copolymer side chains If side chains are built from diblock copolymers, molecular bmshes will exhibit a core-shell-type stmeture. The polymerization techniques that were involved in the stepwise growth of diblock side chains included ATRP, NMP, ROP, or their com-... 

Other copolymer side chains It is well known that the phase diagram of ABC triblock terpo-lymer is much more complex compared to AB diblock copolymers. For molecular brushes with triblock terpolymer side chains, the third block in the side chains additionally influences the conformation in solution and on substrates... 

Block copolymer self-assembly is a very promising alternative to make cylindrical polymer brushes. These brushes can replace the function and roles of molecular bmshes in many fields however, if the response of the main chain is necessary or in the case of multiblock copolymer side chains, they will fail to satisfy the application. 

Molecular brushes with block copolymer side chains add a new dimension to the organization of polymer molecules on surfaces. The conformation of block copolymer bmshes... 

Szarko, J.M. et al. (2010) When function follows form effects of donor copolymer side chains on film morphology and BH) solar cell performance. Adv. Mater., 22 (48), 5468-5472. 

N-(2-Hydroxypropyl)methacrylamide copolymers bearing oligopeptide side chains with a terminal p-nitroaniline (NAp) were incubated with purified lysosomal enzymes (Tritosomes) in vitro, and cleavage of these chains was measured by monitoring the release of NAp. It was shown that certain sequences liberate the terminal residue on incubation at pH 5.5 with lysosomal enzymes Recently, the importance of lysosomal thiol-proteinases in N-(2-hydroxypropyl)methacrylamide copolymer side chain cleavage was discovered The synthesis of side-chain amino acid sequences chosen to match the known specificities of certain lysosomal thiol-proteinases resulted in a higher initial rate of NAp release and a greater extent of release (up to 50% of NAp bound for an incubation period of 5 h) Incubation of substrates in vitro... 

When it became apparent that the lysosomal thiol-proteinases were particularly important in the degradation of HPMA copolymer side-chains, a new series of side-chains was designed to meet known specificities of particular lysosomal enzymes.29 Two side-chains were synthesized (-Gly-Phe-Leu-Gly-Phe-NAp and -Gly-Gly-Phe-Leu-Gly-Phe-NAp) which contain a pentapeptide sequence previously shown O to be susceptible to the lysosomal proteinase cathepsin D, a thiol-independent enzyme. Five further sequences were prepared containing hydrophobic amino acids in the P2 and P positions in relation to the terminal bond (according to the terminology of... 

Design of synthetic copolymer side-chains to facilitate their degradation in lysosomes, Cell Biol, Int. Reports 5 (Suppl.A) (1981)... 

Figure 7 Molecular brushes with block copolymer side chain In selective solvent schematic presentation (a) and pearl-necklace structure In poly(acryllc acld)-Woc/(-poly(/7-butyl acrylate) molecular brushes In toluene (b), dip coated on mica (atomic force microscopy (AFM) phase Image). Adapted from Polotsky, A. V. Charlaganov, M. I. Xu, Y. etal. Macromolecules 200S, 41, 4020. ...

Boemer, H. G., et al. (2001). Synthesis of molecular brushes with block copolymer side chains using atom transfer radical polymerization. Macromolecules, 54(13) 4375 383. 

Long-chain branched polyethylenes can be also obtained by copolymerization of ethene with ethene oligomers by tandem polymerization in one step [100] or with ethene/propene oligomers in two steps [101]. In the latter case, polymers are obtained with crystalline polyethylene backbone chains and amorphic ethene/ propene copolymer side chains [102]. 

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