Nano‐scaled ordering of hyperbranched and star‐hyperbranched polymers

Abstract

Hyperbranched polystyrenes (HPS) were prepared by living radical polymerization of 4-vinylbenzyl N,N-diethyldithiocarbamate (VBDC) as an inimer under UV irradiation. These HPS exhibited large amounts of photofunctional diethyldithiocarbamate (DC) groups on their outside surfaces. We derived star-HPS (SHPS) by grafting from such HPS macroinitiator with methyl methacrylate (MMA) or ethyl methacrylate (EMA). The ratios of radius of gyration to hydrodynamic radius R g /R h for HPS and SHPS in tetrahydrofuran (THF) were in the range of 0.74 -0.90 and 1.05-1.12, respectively. HPS and SHPS behaved in a good solvent as hard and soft spheres, respectively. We demonstrated the structural ordering of both branched polymers in THF through small-angle X-ray scattering (SAXS), by varying the polymer concentration. As a result, HPS and SHPS formed face-centered-cubic (fcc) and body-centered-cubic (bcc) structures, respectively, near the overlap threshold (C*).

Hyperbranched and Highly Branched Polymer Architectures—Synthetic Strategies and Major Characterization Aspects

“…Various cores prepared by SCVP have been applied as hb macroinitiators, e.g., for ROP of CL, photo-RAFT of (methyl)acrylates (Scheme ), cationic polymerization of isobutylene, or the preparation of block-copolymers arms . The later materials could be transformed into conductive core−shell nanoparticles.…”

“…43 PEI was also used as multifunctional initiator for the NCA polymerization of γ-benzyl-L-glutamate, resulting in an amphiphilic star-type structure with a polypeptide shell. 413 Various cores prepared by SCVP have been applied as hb macroinitiators, e.g., for ROP of CL, 414 photo-RAFT of (methyl)acrylates (Scheme 37), 415 cationic polymerization of isobutylene, 416 or the preparation of block-copolymers arms. 417 The later materials could be transformed into conductive core-shell nanoparticles.…”

“…Scheme 37. Synthesis of a hb-Core Star Polymer Based on Self-Condensing UV-Initiated RAFT Vinyl Polymerization415 …”

Synthesis and Self-Assembly Behavior of Four-Arm Poly(ethylene oxide)-b-poly(2-(diethylamino)ethyl methacrylate) Star Block Copolymer in Salt Solutions

“…The star block copolymers offer interesting properties concerning both micellization and microphase separation behavior compared to corresponding linear block copolymers. − The greater proportion of end functional groups induces higher solubility in various solvents compared to linear structure of identical molecular weights. Multiarm PEOs possess three-dimensional branched structures and higher densities of terminal functional groups. − …”

Microporous Films from Diblock Copolymer Micelles Based on Solvent-Induced Mechanism by Temperature Control of Casting Solution

“…Therefore, the mechanism of porous structure is based on the formation of block copolymer micelles similar to our method. Not only diblock copolymers, core-shell nanospheres, and (AB) n stars but also stars with multiarms 27 and star-hyperbranched copolymers 28 formed the lattice of bcc structure near the overlap threshold (C*). This work raises the possibility that such microporous structures would be formed by above highly branched polymers.…”