Toward New Materials Prepared via the RAFT Process: From Drug Delivery to Optoelectronics?

Abstract

IntroductionThe development of controlled/living ionic and radical polymerization techniques during the last decades represents a major breakthrough in polymer chemistry and polymer science. Since these techniques lead to the synthesis of a wide range of tailor-made macromolecular architectures, significant improvements are expected in the current or future application fields of polymers. The industrial impact will however depend on the versatility and applicability of each technique, and of course on the extra cost for the final product.In this context, controlled radical polymerizations (CRP) and especially the reversible addition-fragmentation chain transfer (RAFT) process [1-3] have attracted a lot of attention since they combine the advantages of conventional radical polymerization and living ionic polymerizations. Conventional radical polymerizations are cost-effective techniques, easy to process with a low sensitivity to water and oxygen and applicable to a wide range of monomers. In addition, CRP techniques result in a very efficient control over molecular weight (MW), molecular-weight distribution (MWD), microstructure, chain-end functionality and macromolecular architecture.As shown in the previous chapters of this handbook, the RAFT process appears as one of the most interesting CRP techniques. First, RAFT polymerization is very similar to conventional radical polymerization since it only requires the addition of a chain-transfer agent (CTA) in the medium. Second, RAFT is a very versatile process able to control the (co)polymerization of a large variety of monomers leading to a virtually unlimited macromolecular design library.As a consequence, RAFT polymerization is a well-suited and promising technique to prepare high-performance polymers for a wide range of applications. Indeed, an efficient control at the macromolecular level is a very important step to control and improve the macroscopic properties of the final materials ( Fig. 13.1).

Living Radical Polymerization by the RAFT Process - A Second Update

“…Reviews on specific areas include the kinetics and mechanism of RAFT polymerization, [15][16][17][18] the use of RAFT to probe the kinetics of radical polymerization, [19,20] the use of RAFT in organic synthesis, [21] amphiphilic block copolymer synthesis, [22,23] the synthesis of end functional polymers, [24] the synthesis of star polymers and other complex architectures, [25,26] the use of trithiocarbonate RAFT agents, [27] the use of xanthate RAFT agents (MADIX), [28] polymerization in heterogeneous media, [29][30][31][32] RAFT polymerization initiated with ionizing radiation, [33] polymer synthesis in aqueous solution, [34][35][36][37] surface and particle modification, [38,39] synthesis of self assembling and/or stimuli responsive polymers, [36,40] RAFT-synthesized polymers in drug delivery, [22,41] and other applications of RAFTsynthesized polymers. [30,42,43] The process is also given substantial coverage in most recent reviews that, in part, relate to polymer synthesis, living or controlled polymerization, or novel architectures. Some of these documents are referred to in subsequent sections of this review.…”

“…The use of the corresponding trithiocarbonates 118-125 has also been promoted in this context. [27] Secondary aromatic dithioesters with R = -CHPh(CN) (42) and -CHPh(CO 2 R) (43)(44)(45)(46)(47)(48) and analogous trithiocarbonates 144, 145, and 146-148, respectively, have been shown to have utility in controlling 'R'-connected 79* [227] S S S S NIPAM [240] S S S S 80* [86,241,242] BMA [243] DMAEMA [240][241][242][243] AA [241] BA [243] St [241,243] DMAEMA-b-BMA [243] DMAEMA-b-BA [243] DMAEMA-b-St [243] St-b-HEMA/DMAEMA [86] 81 [244] CN S S…”

Characterization and electrical properties of methyl‐2‐hydroxyethyl cellulose doped with erbium nitrate salt

“…The well‐defined complex macromolecules made by RAFT can be used to build nanostructures such as micelles, vesicles, and nanoparticles 33, 34. In addition, synthetic polymers can be combined with biomolecules or inorganic nanoparticles to address problems in medicine and bio‐ and nano‐technology 35, 37. In some instances the RAFT functionality used to control polymerization can also be used efficiently for subsequent postpolymerization modification to generate complex structures 38–40.…”

Building nanostructures using RAFT polymerization

“…33,34 In addition, synthetic polymers can be combined with biomolecules or inorganic nanoparticles to address problems in medicine and bio-and nano-technology. 35,37 In some instances the RAFT functionality used to control polymerization can also be used efficiently for subsequent postpolymerization modification to generate complex structures. [38][39][40] This present review will highlight a path from monomer incorporation into polymer chains using RAFT polymerization through to macromolecular assembly into nanostructures and is mainly focused on more recent research work.…”