In Situ Synthesis of Branched Block Copolymer Assemblies via RAFT Dispersion Polymerization Using Branched Macro-RAFT Agents

Here,we demonstrate the use of branched macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agents in RAFT dispersion polymerization,to access branched block copolymers as well as well-defined branched block copolymer assemblies.Two types of branched macro-RAFT agents were first synthesized by using either a monofunctional chain transfer monomer or a difunctional chain transfer monomer in RAFT polymerization,and subsequently utilized in RAFT dispersion polymerization.It was found that only branched macro-RAFT agents synthesized from the difunctional chain transfer monomer could lead to colloidally stable assemblies with well-defined morphologies.Reaction conditions including monomer concentration,degree of polymerization (DP) of the core-forming block,and DP of the solvophilic segment on morphologies of branched block copolymer assemblies were investigated in detail.Size exclusion chromatography (SEC) analysis further confirmed the successful formation of branched block copolymers by using branched macro-RAFT agents.This work on the synthesis of branched block copolymer assemblies by RAFT dispersion polymerization offers new opportunities for the rational design of polymer assemblies with well-defined structures.

In Situ Synthesis of Block Copolymer Nano-assemblies by Polymerization- induced Self-assembly under Heterogeneous Condition

Controlled synthesis of amphiphilic block copolymer nanoparticles in a convenient way is an important and interest topic in polymer science. In this review, three formulations of polymerization-induced self-assembly to in situ synthesize block copolymer nanoparticles are briefly introduced, which perform by reversible addition-fragmentation chain transfer （RAFT） polymerization under heterogeneous conditions, e.g., aqueous emulsion RAFT polymerization, dispersion RAFT polymerization and especially the recently proposed seeded RAFT polymerization. The latest developments in several selected areas on the synthesis of block copolymer nano-assemblies are highlighted.

Synchronous Synthesis of Polymeric Vesicles with Controllable Size and Low-Polydispersity by Polymerization-Induced Self-Assembly

Comprehensive Summary The size and size distribution of polymeric nanoparticles have great impact on their physicochemical and biological properties.Polymerization-induced self-assembly(PISA)has been demonstrated to be an efficient method to fabricate various polymeric nanoparticles,among which polymeric vesicles have attracted great interest due to their unique hollow structure.

Template-Directed Fabrication of Anatase TiO2 Hollow Nanoparticles and Their Application in Photocatalytic Degradation of Methyl Orange

Polymerization-induced self-assembly （PISA） was used to fabricate polymeric nanoparticles via reversible ad- dition-fragmentation chain transfer （RAFT） dispersion polymerization of benzyl methacrylate （BzMA） using di- block copolymer poly（glycerol monomethacrytate）-block-poly（2-dimethylaminoetbyl methacrylate） （PGMMA- PDMAEMA-CTA） as the macro RAFT agent. The dispersion of polymeric nanoparticles with a final concentration of about 210 mg/g （solid content of 21%） was obtained via this efficient method （PISA）. The resultant polymeric nanoparticles consisting of corona-shell-core three layers with weak polyelectrolyte PDMAEMA as the shell were used as sacrificial template to fabricate TiO2 hollow nanoparticles. The negatively charged titanium precursor was absorbed into the PDMAEMA shell via the electrostatic interaction, and hydrolyzed to form polymer/TiO2 hybrid nanoparticles. Anatase TiO2 hollow nanoparticles were formed after removing the polymeric templates by calcina- tion at 550 ℃. The experiments of photocatalytic degradation of methyl orange showed that the resultant anatase TiO2 hollow nanoparticles had high photocatalytic activity and good reusability.