Novel α,α‐Bischolesteryl Functional (Co)Polymers: RAFT Radical Polymerization Synthesis and Preliminary Solution Characterization

Abstract

Well-defined poly[pentafluorophenyl (meth)acrylate] (PPFP(M)A) homopolymers are prepared by RAFT radical polymerization mediated by a novel chain transfer agent containing two cholesteryl groups in the R-group fragment. Subsequent reaction with a series of small-molecule amines in the presence of an appropriate Michael acceptor for ω-group end-capping yields a library of novel bischolesteryl functional hydrophilic homopolymers. Two examples of statistical copolymers are also prepared including a biologically relevant sugar derivative. Specific examples of these homopolymers are examined with respect to their ability to self assemble in aqueous media-a process driven entirely by the cholesteryl end groups. In all instances evaluated, and under the preparation conditions examined, the homopolymers aggregate clearly forming polymersomes spanning an impressive size range.

Cholesterol Modified Self-Assemblies and Their Application to Nanomedicine

“…The presence of two spacially close and rigid cholesteryl groups located at the α-chain terminus was observed to drive vesicle formation, even at extremely low levels of incorporation relative to the hydrophilic components in the system. 155,156 In another interesting study, a partially cholesterylsubstituted 8-arm poly(ethylene glycol)-block-poly(L-lactide) star polymer (8-arm PEG-b-PLLA-cholesteryl) exhibited temperature-induced gelation (34 °C) in water, whereas unmodifed 8-arm PEG-b-PLLA failed to gel irrespective of concentration. 157 Further, copolymers based on adenine and thymine methacrylate have also been synthesized with cholesteryl groups located on either one or both ends of the polymer chain.…”

“…Specifically, this approach was applied using homopolymers of N , N -dimethylacrylamide (DMA) and N -(2-hydroxypropyl)­methacrylamide (HPMA), as well as statistical copolymers with N -acryloxysuccinimide (NAS). The presence of two spacially close and rigid cholesteryl groups located at the α-chain terminus was observed to drive vesicle formation, even at extremely low levels of incorporation relative to the hydrophilic components in the system. , …”

Thiol-reactive Passerini-methacrylates and polymorphic surface functional soft matter nanoparticles via ethanolic RAFT dispersion polymerization and post-synthesis modification

“…7,8 While a versatile and straightforward process, there is one aspect that has yet to be fully exploited, namely the preparation of particles containing reactive handles, ideally in the solvophilic shells, that are amenable to chemical modification. Examples of such desirable species include pentafluorophenyl esters 9,10 and azlactone-containing 5,11,12 species. Unfortunately, there is a fundamental incompatibility of these key functional groups with common RAFTDP-PISA formulations.…”

Controlled radical polymerization of fluorinated methacrylates in supercritical CO2: Synthesis and application of a novel RAFT agent

“…It is believed that the key factor to achieve the RAFT polymerization is to design and select a suitable RAFT agent for the target monomer(s) . Up to now, several kinds of RAFT agents, such as dithioesters, trithiocarbonates, xanthates, and dithiocarbamates, have been developed and used for the polymerization of monomers, namely (substituted)styrene, (meth)acrylic acid, (meth)acrylates, and a part of vinyl ethers, while actually most of them are non‐fluorinated monomers. Few RAFT agents are reported to be applied in the controlled radical polymerization of (highly) fluorinated monomers, which hindered the preparation and the application of potential fluorinated functional polymers to a considerable extent.…”