One-Pot Synthesis of Poly(methacrylic acid-co-poly(ethylene oxide) methyl ether methacrylate)-b-polystyrene Amphiphilic Block Copolymers and Their Self-Assemblies in Water via RAFT-Mediated Radical Emulsion Polymerization. A Kinetic Study

A guide to the synthesis of block copolymers using reversible-addition fragmentation chain transfer (RAFT) polymerization

The discovery of reversible-deactivation radical polymerization (RDRP) has provided an avenue for the synthesis of a vast array of polymers with a rich variety of functionality and architecture. The preparation of block copolymers has received significant focus in this burgeoning research field, due to their diverse properties and potential in a wide range of research environments. This tutorial review will address the important concepts behind the design and synthesis of block copolymers using reversible addition-fragmentation chain transfer (RAFT) polymerization. RAFT polymerization is arguably the most versatile of the RDRP methods due to its compatibility with a wide range of functional monomers and reaction media along with its relative ease of use. With an ever increasing array of researchers that possess a variety of backgrounds now turning to RDRP, and RAFT in particular, to prepare their required polymeric materials, it is pertinent to discuss the important points which enable the preparation of high purity functional block copolymers with targeted molar mass and narrow molar mass distribution using RAFT polymerization. The key principles of appropriate RAFT agent selection, the order of monomer addition in block synthesis and potential issues with maintaining high end-group fidelity are addressed. Additionally, techniques which allow block copolymers to be accessed using a combination of RAFT polymerization and complementary techniques are touched upon.

Synthesis of polystyrene nanolatexes via emulsion polymerization using sodium dodecyl sulfonate as the emulsifier

Polystyrene (PS) nanolatexes were successfully prepared via emulsion polymerization using sodium dodecyl sulfonate as the emulsifier. The effects of emulsifier concentration, initiator concentration, polymerization reaction time, and polymerization reaction temperature on particle size and size distribution of PS colloidal spheres were investigated, respectively. The particle size of the diluted polymer emulsion was about 20 nm, as determined by laser scattering. These obtained PS particles were also characterized using Fourier transform infrared spectroscopy and scanning electron microscopy.

Bioinspired amphiphilic phosphate block copolymers as non-fluoride materials to prevent dental erosion

Inspired by the fact that certain natural proteins, e.g. casein phosphopeptide or amelogenin, are able to prevent tooth erosion (mineral loss) and to enhance tooth remineralization, a synthetic amphiphilic diblock copolymer, containing a hydrophilic methacryloyloxyethyl phosphate block (MOEP) and a hydrophobic methyl methacrylate block (MMA), was designed as a novel non-fluoride agent to prevent tooth erosion under acidic conditions. The structure of the polymer, synthesized by reversible addition-fragment transfer (RAFT) polymerization, was confirmed by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). While the hydrophilic PMOEP block within the amphiphilic block copolymer strongly binds to the enamel surface, the PMMA block forms a hydrophobic shell to prevent acid attack on tooth enamel, thus preventing/reducing acid erosion. The polymer treatment not only effectively decreased the mineral loss of hydroxyapatite (HAP) by 36-46% compared to the untreated control, but also protected the surface morphology of the enamel specimen following exposure to acid. Additionally, experimental results confirmed that low pH values and high polymer concentrations facilitate polymer binding. Thus, the preliminary data suggests that this new amphiphilic diblock copolymer has the potential to be used as a non-fluoride ingredient for mouth-rinse or toothpaste to prevent/reduce tooth erosion.

Poly(methacrylic acid)-based AB and ABC block copolymer nano-objects prepared via RAFT alcoholic dispersion polymerization

A series of well-defined amphiphilic methacrylic AB diblock and ABC triblock copolymers are synthesized via polymerization-induced self-assembly using an alcoholic dispersion polymerization formulation.

RAFT polymerization of hydroxy-functional methacrylic monomers under heterogeneous conditions: effect of varying the core-forming block

Do isomeric core-forming blocks afford the same thermo-responsive behavior for diblock copolymer worm gels?

Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method

A many-shot RAFT emulsion polymerization method to synthesize gradient copolymers with high molecular weight and a tailor-made compositional gradient.

Comparison of pseudo-living character of RAFT polymerizations conducted under homogeneous and heterogeneous conditions

Evidence is presented for (i) the greater pseudo-living character of RAFT dispersion polymerization compared to the equivalent solution polymerization and (ii) the presence of monomer-swollen micelles in the former formulation.

Cationic polyelectrolyte-stabilized nanoparticles via RAFT aqueous dispersion polymerization

We report the synthesis of cationic sterically stabilized diblock copolymer nanoparticles via polymerization-induced self-assembly (PISA) using a RAFT aqueous dispersion polymerization formulation. The cationic steric stabilizer is a macromolecular chain-transfer agent (macro-CTA) based on quaternized poly(2-(dimethylamino)ethyl methacrylate) (PQDMA), and the hydrophobic core-forming block is based on poly(2-hydroxypropyl methacrylate) (PHPMA). The effect of varying synthesis parameters such as the salt concentration, solids content, relative block composition, and cationic charge density has been studied. In the absence of salt, self-assembly is problematic because of the strong repulsion between the highly cationic PQDMA stabilizer chains. However, in the presence of salt this problem can be overcome by reducing the charge density within the coronal stabilizer layer by either (i) statistically copolymerizing QDMA monomer with a nonionic comonomer (e.g., glycerol monomethacrylate, GMA) or (ii) using a binary mixture of a PQDMA macro-CTA and a poly(glycerol monomethacrylate) (PGMA) macro-CTA. These cationic diblock copolymer nanoparticles were analyzed by (1)H NMR spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and aqueous electrophoresis. NMR studies suggest that the HPMA polymerization is complete within 2 h at 70 °C. Depending on the specific reaction conditions, either spherical, wormlike or vesicular nanoparticles can be prepared with tunable cationic surface charge.

Direct Molar Mass Determination of Self-Assembled Amphiphilic Block Copolymer Nanoobjects Using Electrospray-Charge Detection Mass Spectrometry

Charge detection mass spectrometry (CD-MS) combined with electrospray ionization was used to determine, in a direct way and for the first time, the molar mass of self-assembled amphiphilic block copolymer nanoobjects prepared via living radical emulsion polymerization. CD-MS supplies enough data for calculating statistically significant measurements of the mass of particles in the megadalton to gigadalton range and their resulting mass distribution.

Living Radical Polymerization by the RAFT Process – A Third Update

This paper provides a third update to the review of reversible deactivation radical polymerization (RDRP) achieved with thiocarbonylthio compounds (ZC(=S)SR) by a mechanism of reversible addition-fragmentation chain transfer (RAFT) that was published in June 2005 (Aust. J. Chem. 2005, 58, 379). The first update was published in November 2006 (Aust. J. Chem. 2006, 59, 669) and the second in December 2009 (Aust. J. Chem. 2009, 62, 1402). This review cites over 700 publications that appeared during the period mid 2009 to early 2012 covering various aspects of RAFT polymerization which include reagent synthesis and properties, kinetics and mechanism of polymerization, novel polymer syntheses, and a diverse range of applications. This period has witnessed further significant developments, particularly in the areas of novel RAFT agents, techniques for end-group transformation, the production of micro/nanoparticles and modified surfaces, and biopolymer conjugates both for therapeutic and diagnostic applications.