Synthesis of linear and 4‐arm star block copolymers of poly(methyl acrylate‐b‐solketal acrylate) by SET‐LRP at 25 °C

Abstract

The new SET‐LRP (using Cu(0) powder for organic synthesis) was successfully used to produce well‐defined linear and star homo‐ and diblock‐copolymers of PMA, PSA, and P(MA‐b‐GA)n (where n = 1 or 4). The kinetic data showed that all SET‐LRP were first order and reached high conversions in a short period of time. The other advantage of using such a system is that the copper can easily be removed through filtration, allowing the production of highly pure polymer. The molecular weight distributions were well controlled with polydispersity indexes below 1.1 and the number‐average molecular weight close to theory, especially upon the addition of Cu(II)Br2/Me6‐TREN complex. The linear and star block copolymers were then hydrolyzed to produce the biocompatible amphiphilic P(MA‐b‐GA)n, where the glycerol side‐groups make the outer block hydrophilic. These blocks were micellized into water and found to have a Rg/RH equal to 0.8 and 1.59 for the liner and star blocks, respectively. This together with the TEM's supported that the linear blocks formed the classical core‐shell micelles, where as, the star blocks formed vesicles. We found direct support for the vesicle structure from a TEM where one vesicle squashed a second vesicle consistent with a hollow structure. Such vesicle structures have potential applications as delivery nanoscaled devices for drugs and other important biomolecules. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6346–6357, 2008

Well-Defined PDMAEA Stars via Cu(0)-Mediated Reversible Deactivation Radical Polymerization

“…56 However, non-functional monomers have been employed (typically methyl acrylate) in all cases, thus limiting the applications of the resultant materials. 57 Herein, we present the Cu(0)-mediated RDRP in dimethyl sulfoxide (DMSO) and isopropanol (IPA) solvents at ambient temperature to afford the synthesis of well-defined 4 and 8 arm PDMAEA stars. Polymerisation of DMAEA in either solvent using Cu(0) wire proceeds with controlled/living characteristics up to ~ 40% conversion, after which significant termination and/or side reactions start to occur as evidenced by SEC.…”

Copolymerization of styrene and methyl methacrylate mediated by iron wire/N,N,N′,N′-tetramethyl-1,2-ethanediamine as catalyst in the presence of air

“…SET LRP technique has numerous advantages in synthesizing well-defined polymers with narrow molecular weight distribution at ambient temperature and in friendly solvent. In a short time, since its appearance, SET LRP has provided the end-group control and the ability to synthesize the polymers with complex architectures, such as branched polymers [16], star polymers [17,18], graft polymers [19,20], etc.…”

The development of peptide-based subunit vaccines against Streptococcus pyogenes, Necator americanus and Schistosome mansoni

“…In this work, we used copper wire (Cu 0 ). There are several advantages of the use of copper wire: the presence of an excess copper repository; easy removal of copper wire upon completion of the reaction; and the possibility of reusing the copper wire for the next reaction (cost effective) [25,39]. The chemistry behind the use of copper wire has been established.…”

“…For example, in Brucella abortus bacteria, Pam 3 -modified cysteine was shown to be involved in bacterial defence mechanism by down regulating host's immune system [38]. However, when Pam 3 Cys was used as adjuvant, it was able to stimulate immune response against co-delivered antigen, and did not result in the immune system down regulation [37,39,40]. Though the lipid core component of the LCP mimics the lipophilic part of Pam 3 Cys, the use of LCP as adjuvant is more advantageous as the LCP can easily be synthesized following Boc or Fmoc solid phase peptide synthesis (SPPS) protocols [41].…”

“…Nevertheless, the application of CuAAC for biological compounds is controversial in regards to copper toxicity and the use of the reducing agent. For example there were reports that active copper species readily form radicals that can (partially) degrade or destroy peptides and protein complexes during CuAAC reactions, while in in vitro system, copper complexes may be taken up by cells, thus altering cellular metabolisms and functions [38,39]. To overcome these limitations, CuAAC-cell compatibility can be improved by either, the use of water-soluble ligands (e.g., bis-(L-histidine) [40]) or, in some cases, the use of accelerating CuI-ligands that allowed low CuI loading during catalytic reaction [41].…”