Well‐defined ABC triblock copolymers based on two hydrophilic blocks, A and C, and a hydrophobic block B are synthesized and their self‐assembly behavior is investigated. Interestingly, at the same solvent, concentration, pH, and temperature, different shape micelles are observed, spherical and worm‐like micelles, depending on the preparation method. Specifically, spherical micelles are observed with bulk rehydration while both spherical and worm‐like micelles are observed with film rehydration.
The construction of macro-molecular system containing multiple redox centers or photosensitizers is aimportant subject in the design of molecular electronidevices.1,2 For such objectives, systematization of donor-redox center-acceptor triad molecules into largmolecular systems is one of the most feasible approaches, because the exquisite incorporation of thphotosensitizers and suitable electron donors and/oacceptors into a polymeric chain is useful for varioumolecular electronic systems.3-5 Th… 相似文献
A one‐pot procedure that straightforwardly combines reversible addition‐fragmentation chain transfer (RAFT) polymerization and end group transformation to remove the RAFT end groups is developed for the synthesis of well‐defined poly(meth)acrylates and polyacrylamides with inert end groups. This procedure only requires the addition of an amine at the end of the standard RAFT polymerization procedure, which avoids the separation and purification of the intermediate polymers and, hence, extremely reduces the working time and utilized amount of solvents. Upon addition of the amine, a thiol group is formed by aminolysis of the thiocarbonylthio group, which subsequently undergoes Michael addition with unreacted monomer leading to an inert thioether functionalized polymer.
As some complexes of transition metal cations in high oxidation state can oxidize tertiary amines under proper conditions into aminoalkyl radicals to initiate polymerization of electron‐deficient vinylic monomers, they form mono‐centered redox‐initiation pairs for preparation of 100% alpha‐amino telechelic polymer. Radical emulsion polymerization of methyl methacrylate (MMA) is performed by using water‐soluble amines as a reducing agent and FeIII or CuII as an oxidizing agent. Tertiary amines such as 2‐(N,N‐dialkylamino)ethanol and N,N,N′,N′‐tertramethylethylenediamine exhibit a higher initiation activity. Monomer conversion can reach 80% in 8 h and 95% in 16 h, leading to PMMA with an absolute weight‐average molecular weight above 1.5 × 106 g mol?1. The alpha‐amino terminal functionality is verified by ultraviolet‐induced diarylketone‐initiated radical bock polymerization by using these PMMA chains as the macro‐sensitizer. Such a facile heterogeneous technique results in syndiotactic‐rich high‐Tg PMMA (rr > 50%, Tg = 124–127 °C). PMMA chains may be oxidized by FeII–O2 complexes to initiate further radical polymerization, leading to PMMA with a long‐chain branched architecture.
A novel diblock copolymer consisting of poly(vinylferrocene) (PVFc) and poly(N,N‐diethylacrylamide) (PDEA) is synthesized via a combination of anionic and RAFT polymerization. The use of a novel route to hydroxyl‐end‐functionalized metallopolymers in anionic polymerization and subsequent esterification with a RAFT agent leads to a PVFc macro‐CTA ( = 3800 g mol−1; Đ = 1.17). RAFT polymerization with DEA affords block copolymers as evidenced by 1H NMR spectroscopy as well as size exclusion chromatography (6400 ≤ ≤ 33700 g mol−1; 1.31 ≤ Đ 1.28). Self‐assembly of the amphiphilic block copolymers in aqueous solution leads to micelles as shown via TEM. Importantly, the distinct thermo‐responsive and redox‐responsive character of the blocks is probed via dynamic light scattering and found to be individually and repeatedly addressable.
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