Polymerization-Induced Self-Assembly (PISA) Using ICAR ATRP at Low Catalyst Concentration

Abstract

Polymerization-induced self-assembly (PISA) was achieved by conducting an initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) at low ppm of copper catalyst concentration. A poly(oligo(ethylene oxide) methyl ether methacrylate) 50 (POEOMA 50 ) macroinitiator and stabilizer was synthesized by an aqueous ICAR ATRP using Cu II Cl 2 /tris(pyridin-2-ylmethyl)amine (TPMA) complex. Subsequently, the dispersion polymerization of benzyl methacrylate (BnMA) in ethanol was realized with a Cu II Br 2 /TPMA complex either at room temperature or at 65 °C using V-70 or AIBN as radical initiators, respectively. The effect of catalyst concentration, radical initiators, targeted degree of polymerization (DP) of PBnMA, solids content, and temperature on the molecular characteristics and self-assembly behavior of block copolymers POEOMA−PBnMA was evaluated by gel permeation chromatography (GPC), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Block copolymers assembled into spheres, wormlike aggregates, and vesicles with diameters ranging from 100 to 600 nm, depending on the temperature, solids content, and the DP of PBnMA. The effect of the temperature on the polymerization behavior and morphological evolution was attributed to the temperature-dependent plasticization of the core-forming PBnMA block above and below its glass transition temperature (T g = 54 °C).

In Situ Crosslinking of Nanoparticles in Polymerization‐Induced Self‐Assembly via ARGET ATRP of Glycidyl Methacrylate

“…From Figure b, the inflection point between the first and second stages can be located at monomer conversion of ≈8%, which actually corresponded to the onset of the turbidity and beginning of the micellar nucleation. Finally, in the third stage, the double bond was mostly polymerized and the monomer conversion reached completion after 4.0 h. This phenomenon was similar to other PISA systems reported in the literature and ATRP PISA in our previous work . However, the kinetics plot for conversion of the oxirane rings showed a slower polymerization rate.…”

“…According to our previous work, the macroinitiator/stabilizer of PEOEMA was prepared by ICAR ATRP of OEOMA 300 monomer using Cu II Br 2 /TPMA complex as the catalytic system, HEBiB as initiator, AIBN as initiator and water as solvent. POEOMA with an M w / M n of 1.52 and an apparent molar mass of 8100 g mol −1 was obtained ( Figure a).…”

“…TPMA and 2‐hydroxyethyl 2‐bromoisobutyrate (HEBiB) were prepared according to the literature. The POEOMA macroinitiator/stabilizer was synthesized according to our previous work by ICAR ATRP at 45 °C using 2,2′‐azobis (2‐methylpropionamide) dihydrochloride (VA‐044) as initiator, complex of Cu II Br 2 /TPMA as catalyst, and water as solvent . All other chemicals were used as received unless otherwise specified.…”

Evolution of Morphology of POEGMA‐b‐PBzMA Nano‐Objects Formed by PISA

“…When the polymerization reached full conversion, the chain length of each block and their packing parameter were constant, thus the morphology should be fixed regardless of the heating time. However, when the system was kept above the glass transition temperature of the PBzMA (54 °C) segment, the moveable polymer chains were driven to transcend the kinetically trapping phenomenon and further reorganize the self‐assemblies and reach a true equilibrium morphology. Therefore, the initially formed sphere‐aggregates fused together to form long worm‐like structures that then entangled to form vesicles.…”

ICAR ATRP in PEG with Low Concentration of Cu(II) Catalyst: A Versatile Method for Synthesis of Block Copolymer Nanoassemblies under Dispersion Polymerization

“…This ICAR ATRP under PISA can be employed in a large range of monomers and well‐defined polymers including block copolymers can be obtained. However, just fewer samples of ICAR ATRP dispersion polymerization under PISA conditions are reported …”