In Situ Use of Aqueous RAFT Prepared Poly(2‐(diethylamino)ethyl methacrylate) as a Stabilizer for Preparation of CO₂ Switchable Latexes

Abstract

Poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) macroinitiator is prepared in water by aqueous reversible addition–fragmentation chain transfer (RAFT) polymerization under CO2 atmosphere, and then used directly as a stabilizer in emulsion polymerization, without requiring further purification, to yield CO2‐switchable latexes of poly(methyl methacrylate) (PMMA) and polystyrene (PS). Chain extension of the PDEAEMA macroinitiator with styrene (S) leads to the in situ formation of poly(DEAEMA‐b‐S) diblock copolymers in a one‐pot process. The final latexes are pH and CO2‐responsive and can be coagulated by N2 bubbling and subsequently redispersed by CO2 bubbling. The effects of various parameters on the latex properties are investigated, including pH, concentration of macro‐RAFT agent, using MMA as comonomer and initiator concentration. The results show that replacing only 5 mol% MMA in emulsion polymerization of styrene eliminates the induction time and also has a significant influence on the particle size distribution.

RAFT‐Mediated Polymerization‐Induced Self‐Assembly

“…Thev alue of the use of CO 2 was also illustrated in ad ifferent way,b yt he preparation of CO 2 -responsive particles.A mong other approaches,P ISA has been used for the synthesis of CO 2 -switchable latexes.T he Cunningham group [152] used aP DEAEMA macroRAFT agent for the synthesis of PS or PMMA particles with ashell that was both pH-and CO 2 -responsive,w hich are actually related properties.The tertiary amine groups of the DEAEMA units can be protonated by introducing CO 2 and reversibly deprotonated by CO 2 removal, thus allowing particle coagulation/redispersion cycles.…”

Synthesis of well-defined epoxy-functional spherical nanoparticles by RAFT aqueous emulsion polymerization

“…35 Subsequently, PISA has been extended to include various dispersion polymerization formulations conducted in either aqueous, 36 alcoholic or non-polar media, 32 while RAFT aqueous emulsion polymerization has continued to be explored by various groups. 28,30,31,[37][38][39][40] PISA formulations based on dispersion polymerization usually allow facile access to many nanoparticle morphologies, including spheres, worms and vesicles. 36,41 In contrast, RAFT aqueous emulsion polymerizations often result in the formation of kinetically-trapped spheres, particularly for methacrylic core-forming blocks based on methyl methacrylate, [42][43][44][45] n-butyl methacrylate, 46,47 benzyl methacrylate 48 or 2,2,2-trifluoroethyl methacrylate.…”

RAFT‐vermittelte polymerisationsinduzierte Selbstorganisation (PISA)

“…In jüngerer Zeit berichteten Xu et al auch über die MMA-Dispersionspolymerisation in scCO 2 ,j edoch unter Verwendung eines Poly(dodecafluoroheptylmethacrylat)-MacroRAFT-Agens. [149] [152] verwendete ein PDEAEMA-MacroRAFT-Agens fürd ie Synthese von PS-oder PMMA-Partikeln mit einer Hülle,d ie sowohl auf pH-Wert-¾nderungen als auch auf CO 2 reagierte,w as tatsächlich verwandte Eigenschaften sind. Die tertiären Amingruppen der DEAEMA-Einheiten kçnnen durch Einführung von CO 2 protoniert und durch Entfernung von CO 2 reversibel deprotoniert werden, wodurch Partikelkoagulations-/Redispergierungszyklen ermçglicht werden.…”