Nanoparticles graft copolymers

Keywords Block copolymers ABC triblock copolymers Janus micelles Cylinder brushes Core-shell nanoparticles Graft copolymers Micelles Vesicles Copolyampholytes Polyelectrolyte block copolymers Aggregation... 

The formation of stable nanoparticles has been studied using various derivatives of thermosensitive PNIPAM, including diblock and graft copolymers, PNIPAM-b-PEO and PNIPAM-g-PEO [165-172], In these copolymers, the role of the PEO chains is to solubilise/stabilise collapsed PNIPAM at temperatures above its cloud point. Both the graft and the block copolymers, PNIPAM-g-PEO and PNIPAM-fr-PEO, form spherical core-shell structures in... 

Enzymatic polymerizations have been established as a promising and versatile technique in the synthetic toolbox of polymer chemists. The applicability of this technique for homo- and copolymerizations has been known for some time. With the increasing number of reports on the synthesis of more complex structures like block copolymers, graft copolymers, chiral (co)polymers, and chiral crosslinked nanoparticles, its potential further increases. Although not a controlled polymerization technique itself, clever reaction design and integration with other polymerization techniques like controlled radical polymerization allows the procurement of well-defined polymer structures. Specific unique attributes of the enzyme can be applied... 

Sakuma, S., Hayashi, M., and Akashi, M. Design of nanoparticles composed of graft copolymers for oral peptide delivery. Adv. Drug Del. Rev. 47 21—37, 2001. 

Finally, it is shown that non-linear amphiphilic structures show different aggregation behavior as compared to block copolymers. Graft copolymers with non-polar backbone polyelectrolyte side chains have a smaller tendency to form micelles than their block copolymer analogs which is attributed to the more facile stabilization of unimers by the sidechains. In contrast, unimolecular micelles are the only possibility for core-shell nanoparticles. Janus micelles, on the other hand, form unique non-centrosymmetrical micelles that have a strong tendency to form centrosymmetrical supermicelles. 

The synthesis of core-shell magnetic nanoparticles from polyacrylic acid (PAA) graft copolymers containing side chains of PEO and PPO (Fig. 5) was demonstrated by Hatton et al. [102]. Using a mixture of the polymers at a temperature of 180°C, amine-terminated PEO and PPO were coupled onto the PAA via amidation. Super-paramagnetic polymer-coated nanoparticles were synthesized by the hydrolysis and condensation of Fe(II) and Fe(III) chloride salts in the presence of PPO- or PEO-modified PAA copolymers. The extraction of organic compounds from aqueous media towards the copolymer shell of hydrophobic PPO segments can be applied in the field of water purification. 

Carrot, G., VaImalette,J. C., et al. Gold nanoparticle synthesis in graft copolymer micelles. CoUoid Polymer Science,276(10), 853-859 (1998). 

Artursson, P., Brown, L., Dix, J., Goddard, P., and Petrak, K., 1990, Preparation ofsterically stabilized nanoparticles by desolvation from graft copolymers, J. Polym. Set, Parr A Polym. Chem. 28 2651-2663. 

Micelles that are pH responsive are the nanoparticles of amphiphilic block copolymers or graft copolymers consisting of pH-responsive blocks. At the neutral pH, the insoluble blocks aggregate to form a core and the soluble blocks form a shell (or corona). The pH-responsive blocks may form pH-responsive cores,shells,or both. Polymeric micelles with polybase cores such as PDEA, poly(2-(diisopropylamino)ethyl methacrylate) (PDPA), ... 

Kolya H, Pal S, Pandey A, Tripathy T. Preparation of gold nanoparticles by a novel biodegradable graft copolymer sodium alginate-g-poly (N, N-dimethylacrylamide-co-acrylic acid) with anti micro bacterial application. Eur Polym J. 2015 66 139-48. 

While end-functional polymers are clearly important industrial products for materials synthesis, they are also interesting from an academic point of view. Many complex macromolecular architectures can be realized from end-functional polymeric starting materials. Two mono-telechelic polymers can, for example, be joined to form a diblock copolymer, or several such polymers can be joined to form star-like polymers. Mono-telechelic polymers can also be attached to a linear, multifunctional polymer to yield graft copolymers. Depending on the functional end group, such polymers can attach to macroscopic or nanoparticle surfaces or form conjugates with bio-oligomers [5] or biomacromolecules [6]. 

Q. Yuan, R. Venkatasubramanian, S. Hein, and R. Misra, A stimulus-responsive magnetic nanoparticle drug carrier Magnetite encapsulated by chitosan-grafted-copolymer, Acta Biomaterialia, 4 (4), 1024-1037, 2008. 

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