Communication
Macromolecular
Rapid Communications
wileyonlinelibrary.com 813 DOI: 10.1002/marc.201300889
1. Introduction
The self-directed assembly of amphiphilic surfactants
and copolymers in a selective solvent at, or above, a crit-
ical temperature and concentration is well documented
and results in the formation of nanosized particles with
an impressive range of solution morphologies including
micelles, cylinders, and vesicles.
[1]
In the case of polymers,
this has involved, by necessity, the synthesis of suitable
amphiphilic block copolymers that may have AB-, ABA-, or
ABC-type topologies with suitable molar compositions. As
a consequence of the required block architecture, an appro-
priate polymerization technique must be employed that
allows for the control of copolymer molecular weight,
composition (hydrophilic–hydrophobic balance), and dis-
persity, since each of these features is known to play a
role in the self-assembly process and on the final solu-
tion morphology formed.
[2]
Fortunately, the discovery and
development of the suite of reversible deactivation radical
polymerizations (RDRPs) now allows for the direct syn-
thesis of almost any conceivable type of block copolymer
with respect to functionality, composition, topology, and
overall architecture.
In homopolymers, or copolymers, of sufficiently low
molecular weight, the nature of the end groups becomes
an important consideration with respect to the bulk
and solution properties since these groups can repre-
sent an overall significant weight/molar fraction of the
polymeric material.
[3]
For example, Furyk et al.
[4]
have
evaluated the effect of end groups on the lower critical
Well-defined poly[pentafluorophenyl (meth)acrylate] (PPFP(M)A) homopolymers are pre-
pared 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.
Novel α, α-Bischolesteryl Functional (Co)Polymers:
RAFT Radical Polymerization Synthesis and
Preliminary Solution Characterization
Peter J. Roth, Thomas P. Davis, Andrew B. Lowe*
Dr. P. J. Roth, Prof. A. B. Lowe
Centre for Advanced Macromolecular Design (CAMD),
School of Chemical Engineering, University of New South
Wales, Kensington, Sydney, NSW 2052, Australia
E-mail: a.lowe@unsw.edu.au
Prof. T. P. Davis
Monash Institute of Pharmaceutical Sciences, Monash
University, Parkville, VIC 3052, Australia
Prof. T. P. Davis
Department of Chemistry, University of Warwick, Gibbet Hill,
Coventry, CV4 7AL, UK
Macromol. Rapid Commun. 2014, 35, 813−820
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim