Experimental Evidence and Beneficial Use of Confined Space Effect in Nitroxide-Mediated Radical Microemulsion Polymerization (Microemulsion NMP) of n-Butyl Acrylate

Abstract

The confined space effect, which was found by the authors, in nitroxide-mediated radical polymerization (NMP) in a microemulsion system (microemulsion NMP) of n-butyl acrylate (BA) was investigated, where the diameter of micelles (monomer droplets) was 5−10 nm and that of poly(BA) (PBA) particles at the completion of the polymerization was ∼60 nm. To clarify the importance of diameter of monomer droplets (d m ) in the initial stage of the microemulsion NMP, NMP in a miniemulsion system (miniemulsion NMP) (d m : ∼60 nm) was carried out as a comparative experiment. The miniemulsion NMP proceeded without molecular weight distribution (MWD) control; on the other hand, in the microemulsion NMP the MWD shifted to higher molecular weight with increasing conversion. The livingnesses of PBAs obtained in the initial stages of the miniemulsion and microemulsion NMPs, which were determined by chain extension test, were 0.01% and 64%, respectively. From these results, it is concluded that the confined space effect in the initial stage of the microemulsion NMP effectively operated and resulted in PBA with predetermined molecular weight and good control of MWD even if the diameter of polymerizing particles increased with conversion.

4-Dimensional Modeling Strategy for an Improved Understanding of Miniemulsion NMP of Acrylates Initiated by SG1-Macroinitiator

“…As discussed above for a single d p of 50 nm, nitroxide partitioning greatly affects the NMP characteristics. Figure 7 shows that the previous observation can be generalized to experimentally accessible particle diameters ranging between 20 and 80 nm, 40 focusing on a conversion of 0.7 and considering a broader range of Γ values (Γ = 50, 100, 200, 500, and 5000). For the reference case, as discussed above, a Γ value of 50 was selected based on an arbitrary factor of 2 compared to the Γ value of ca.…”

Bilayer‐Templated Two‐Dimensional RAFT Polymerization for Directed Assembly of Polymer Nanostructures

“…Although one might envision some conceptual similarities between vesicle‐templated and emulsion polymerizations, there are two important distinctions. The confinement of monomers ensures the two‐dimensional propagation of the growing polymer chains, and vesicles show high longitudinal stability in the timescale of the polymerization, unlike microemulsions …”

Synthesis of silica/PAA NPs via combining RAFT polymerization and thiol‐ene click reaction and postpolymerization modifications with arsenazo (III)

“…Reactive polymer scaffolds containing functional and reactive side chain units have emerged as important building blocks for the preparation of well-defined and functional macromolecular architectures or polymer-coated surfaces over the last 10 years. [11][12][13][14][15] Controlled radical polymerization methods such as atom transfer radical polymerization, [16][17][18] nitroxide-mediated polymerization, [19][20][21] and reversible addition-fragmentation chain transfer (RAFT) [22][23][24] procedures have made possible the synthesis of functionally diverse polymers with predetermined chemical compositions and low dispersities using a wide variety of monomer types and polymerization conditions. Despite the versatility of these methods, postpolymerization modification techniques are still needed as a powerful tool for building functional polymer structures due to the incompatibility or susceptibility of desired monomers toward the polymerization conditions.…”

“…Reactive polymer scaffolds containing functional and reactive side chain units have emerged as important building blocks for the preparation of well‐defined and functional macromolecular architectures or polymer‐coated surfaces over the last 10 years . Controlled radical polymerization methods such as atom transfer radical polymerization, nitroxide‐mediated polymerization, and reversible addition‐fragmentation chain transfer (RAFT) procedures have made possible the synthesis of functionally diverse polymers with predetermined chemical compositions and low dispersities using a wide variety of monomer types and polymerization conditions.…”