Use of an Amphiphilic Block Copolymer as a Stabilizer and a Macroinitiator in Miniemulsion Polymerization under AGET ATRP Conditions

Abstract

Controlled free-radical polymerization 1 has become an intensively investigated area of research due to its high tolerance of polar functionalities and its ability to develop well-defined macromolecular architectures (e.g., stable free-radical polymerization, 2 atom transfer radical polymerization (ATRP), 3-5 reversible addition-fragmentation chain transfer, 6 and degenerative chain transfer polymerization 7 ). Recently, attempts to conduct the synthesis of well-defined polymers by ATRP in more environmentally friendly media, such as aqueous dispersed systems, have been explored. 8 In particular, the miniemulsion polymerization approach 9 is well-suited to enhance the colloidal stability and facilitate a controlled radical polymerization by eliminating the requirement for mass transfer of the radical activator/deactivator through the aqueous phase, normally occurring during an emulsion polymerization. 10,11 Under miniemulsion conditions, block copolymers can be successfully synthesized using the simultaneous reverse and normal initiation (SR&NI) 12 or activator generated by electron transfer (AGET), 13 both requiring the use of surfactants as particle stabilizers

Recent Research Progress in the Synthesis and Properties of Amphiphilic Block Co-polymers and Their Applications in Emulsion Polymerization

“…Emulsion polymerization with amphiphilic co-polymer stabilizers created in situ from well-defined hydrophilic homo-polymers bearing a reactive group, such as thiocarbonylthio end-group [45,46], alkoxyamine end-group [30] and halogen endgroup [60], will probably open the door to new developments in surfactant-free emulsion polymerization. Polymer latexes prepared by this approach do not contain low-molecular-weight surfactants and by covalently linking the stabilizer to the polymer particle surface.…”

Atom transfer radical polymerization in aqueous dispersed media

“…They can efficiently bind surfactant with the latex particles, and avoid the possible surfactant migration from the latex upon film formation. Recently, an amphiphilic block copolymer was used as a surfactant as well as a macroinitiator for ATRP in miniemulsion [66]. A well-defined poly(ethylene oxide)-b-polystyrene diblock copolymer (PEO-b-PSt-Br) was synthesized using ATRP for chain extension from a halogen-functionalized PEO macroinitiator.…”

Recent advances in controlled/living radical polymerization in emulsion and dispersion

“…142 In addition, the use of PEO-b-PSt-Br amphiphilic block copolymer was also examined as a polymeric stabilizer as well as a macroinitiator for ATRP to prepare well-controlled triblock copolymers under miniemulsion conditions. 143 However, anionic surfactants have not been successfully incorporated into miniemulsion ATRP, because of their ability to deactivate metal complexes. In consequence of the recent development of more robust AGET process for ATRP, various polymers with more complex architectures have been successfully prepared in miniemulsion systems.…”