Control of Particle Morphology in Ab Initio RAFT Mediated Emulsion Polymerization

Abstract

Recent advances in the use of reversible addition–fragmentation chain transfer (RAFT) polymerization in dispersed phase systems have paved the way for the fine control of the morphology of latex particles that was not possible by conventional free radical polymerization techniques. With this approach, living amphiphilic block copolymers are synthesized that self-assemble to form micelles. The hydrophilic segment is formed from a water-soluble monomer which stabilizes the latex particles as polymerization proceeds and the latex particles grow. The hydrophobic ends of the RAFT diblocks ultimately grow into the polymer that forms the body of the particles. This paper presents examples of ways in which these advances can be used to engineer latex particles with unique morphologies that exhibit specific application properties.

Molecular Weight and Tacticity of Oligoacrylates by Capillary Electrophoresis - Mass Spectrometry

“…Charged polymers, polyelectrolytes, have a fascinating ability to interact with their environment. Short polyelectrolyte chains, oligoelectrolytes, have been used to stabilize emulsions [1] and play a key role in paints and coatings, [2][3][4] controlled mineralization [5][6][7] as well as other applications. [8] This article proposes new and advanced characterization of these oligoelectrolytes.…”

Block copolymer synthesis by controlled/living radical polymerisation in heterogeneous systems

“…Following this, a short n BuA or St block was included in the macro-RAFT agent to introduce amphiphilicity into the CTA and to prevent the initial formation of droplets. 133 The group prepared PAA-b-P n BuA-b-PSt-b-P n BuA and PAA-b-PSt-b-P( n BuA-co-MMA) from PAA-b-P n BuA-TTC and PAA-b-PSt-TTC macro-RAFT agents, respectively, although no macromolecular characterisation was provided to compare to their earlier study. Luo et al also adopted PAA-b-PSt-TTC as a macro-RAFT agent and surfactant in a sequential aqueous emulsion route to PSt-b-P n BuA-b-PSt (SBAS).…”

“…102 Sprone et al later demonstrated means by which to influence the identity of core and shell blocks within symmetric PSt-b-P n BuA and PSt-b-(P n BuA-co-PMMA) particles. 133 Although the more hydrophobic PSt energetically prefers to form the particle core, using PAA-b-P n BuA-TTC produced core-shell particles with P n BuA cores. Alternatively, using PAA-b-PSt-TTC resulted in unusual deformed particles with mixed shells comprising inclusions of PSt amongst domains of the more hydrophilic P n BuAco-PMMA.…”

“…Arguably the most promising modification of ab initio CLRP is the use of a macroCTA or macroinitiator that also functions as a surfactant, which typically enables simultaneous control over the polymerisation and colloidal stability, and as such the strategy is now commonplace. 133,107,108,109,111,114,112,117 In RAFT, using an amphiphilic macro-RAFT agent immediately localises the CTA at the polymerisation loci, i.e. within micelles.…”

RAFT Polymerization: Materials of The Future, Science of Today: Radical Polymerization - The Next Stage

“…Sprong et al [19] show that particle morphology developed in ab initio RAFT emulsion polymerization depends on the nature of the amphiphilic macro RAFT agent used. Destarac et al [20] examine thermoresponsive amphiphilic block copolymers prepared with xanthate RAFT agents (MADIX) as stimuli responsive emulsion stabilizers.…”