Precise Synthesis of Miktoarm Star Polymers by Using a New Dual-Functionalized 1,1-Diphenylethylene Derivative in Conjunction with Living Anionic Polymerization System

1,3-Pentadiene-Assistant Living Anionic Terpolymerization: Composition Impact on Kinetics and Microstructure Sequence Primary Analysis

The combination of a living anionic technology and a unique alternating strategy provided an exciting opportunity to prepare novel and well-defined poly(1,3-pentadiene-co-syrene-co-1,1-diphenylethylene) resins consisting of three alternating sequences of modules (A/B/C zwitterions). "A" being Styrene (St)/1,3-pentadiene (PD), "B" being diphenylethylene (DPE)/PD, "A" being DPE/St, respectively, A wide composition range of new polyolefin resins, i.e., poly (A-co-B), poly (A-co-C), and poly (B-co-C), with controlled molecular weight and very narrow molecular weight and composition distributions have been prepared by a one-pot living characteristic method. In the section of kinetic analysis, the terpolymer yields and kinetic parameters were strongly dependent on the feed/comonomer ratio as well as the content of the alternating structure. The competition copolymerization behaviors of A/B, B/C, and A/C were studied in detail in this work. By contrast, the microstructure and the thermal property of the resulting terpolymer were investigated via Nuclear magnetic resonance (NMR) and Differential scanning calorimetry (DSC) analysis. The results of 1H NMR tracking the change of [Aromatic ring]/[C=C] value indicated the distinctive copolymer-ization behavior of the selective "alternating-modules". The glass transition temperature (T_g) was very sensitive to the terpolymer composition. By contrast to poly(A-ran-B) with only one obvious T_g, there were two T_gs in the A/C and B/C copolymerization cases. Moreover, the desirable high T_g ~ 140 °C resin was limited to the terpolymers with up to 50 mol % DPE. Finally, the "ABC-X" mechanism was proposed to interpret the unique terpolymerization behavior, which belongs to the classical "bond-forming initiation" theory.

Photocontrolled bromine–iodine transformation reversible-deactivation radical polymerization: facile synthesis of star copolymers and unimolecular micelles

A facile strategy of synthesizing star copolymers was successfully established via photocontrolled BIT-RDRP. The obtained copolymers have well-defined four-arm amphiphilic block architecture and can form stable unimolecular micelles in water.

Investigation of the features in living anionic polymerization with styrene derivatives containing annular substituents

Five styrene derivatives with annular substituents (SAs), called CPBE, CHBE, THNE, THBE and META, were successfully synthesized and living anionic polymerization was conducted.

A fast semi-continuous anionic process for fluorene-functionalized homo and block oligomers with uniform molecular weights

A semi-continuous strategy based on anionic reactions was developed for the step-by-step synthesis of oligomers with uniform molecular weights.

Precise Synthesis of Macromolecular Architectures by Novel Iterative Methodology Combining Living Anionic Polymerization with Specially Designed Linking Chemistry

This article reviews the development of a novel all-around iterative methodology combining living anionic polymerization with specially designed linking chemistry for macromolecular architecture syntheses. The methodology is designed in such a way that the same reaction site is always regenerated after the polymer chain is introduced in each reaction sequence, and this "polymer chain introduction and regeneration of the same reaction site" sequence is repeatable. Accordingly, the polymer chain can be successively and, in principle, limitlessly introduced to construct macromolecular architectures. With this iterative methodology, a variety of synthetically difficult macromolecular architectures, i.e., multicomponent μ-star polymers, high generation dendrimer-like hyperbranched polymers, exactly defined graft polymers, and multiblock polymers having more than three blocks, were successfully synthesized.

Synthesis and self-assembly of a dual-responsive monocleavable ABCD star quaterpolymer

A modularly synthesized core-functionalized PEG-PSt-PCL-PAA miktoarm star can self-assemble into hollow nanocapsules that are sensitive to pH/redox stimuli and H-bond/polyion complexation.

Synthesis and properties of couplable ABCDE star copolymers by orthogonal CuAAC and Diels–Alder click reactions

Well-defined ABCDE star quintopolymers generated by a modular and orthogonal strategy could self-assemble into intriguing nanoobjects sensitive to thermal and pH stimuli.

Syntheses of exactly-defined multi-graft polymers with two or more graft chains per branch point by a new iterative methodology

A new type of multi-graft polymers has been successfully synthesized by living anionic polymerization using a difunctional core agent.

Facile synthesis of multiarmed and multicomponent star polymers by a new iterative methodology using (formyl-protected 1,3-dioxolane)-end-functionalized polymer anions

In this manuscript, we have developed a new and efficient iterative methodology using formyl-protected 1,3-dioxolane-end-functionalized polymer anions for the facile synthesis of multiarmed and multicomponent miktoarm star polymers.

Monomer sequence determination in the living anionic copolymerization of styrene and asymmetric bi-functionalized 1,1-diphenylethylene derivatives

In-chain functionalized polystyrenes with different sequential arrangements of functional groups are preparedvialiving anionic copolymerization. The sequence structures are determined by time sampling to establish the sequence-determination method.

Synthesis and properties of an acid-labile dual-sensitive ABCD star quaterpolymer

Copolymer aggregates formed from an amphiphilic ABCD star could exhibit acid-induced topological and morphological transformations and stimuli-triggered drug delivery properties.

New polymethylene-based AB2 star copolymers synthesized via a combination of polyhomologation of ylides and atom transfer radical polymerization

Polymethylene-based AB₂ star copolymers were synthesized. PM-b-(PS)₂ porous films and particles were fabricated via static breath-figure process and electrospraying, respectively.

Probing the self-assembled nanostructures of functional polymers with synchrotron grazing incidence X-ray scattering

For advanced functional polymers such as biopolymers, biomimic polymers, brush polymers, star polymers, dendritic polymers, and block copolymers, information about their surface structures, morphologies, and atomic structures is essential for understanding their properties and investigating their potential applications. Grazing incidence X-ray scattering (GIXS) is established for the last 15 years as the most powerful, versatile, and nondestructive tool for determining these structural details when performed with the aid of an advanced third-generation synchrotron radiation source with high flux, high energy resolution, energy tunability, and small beam size. One particular merit of this technique is that GIXS data can be obtained facilely for material specimens of any size, type, or shape. However, GIXS data analysis requires an understanding of GIXS theory and of refraction and reflection effects, and for any given material specimen, the best methods for extracting the form factor and the structure factor from the data need to be established. GIXS theory is reviewed here from the perspective of practical GIXS measurements and quantitative data analysis. In addition, schemes are discussed for the detailed analysis of GIXS data for the various self-assembled nanostructures of functional homopolymers, brush, star, and dendritic polymers, and block copolymers. Moreover, enhancements to the GIXS technique are discussed that can significantly improve its structure analysis by using the new synchrotron radiation sources such as third-generation X-ray sources with picosecond pulses and partial coherence and fourth-generation X-ray laser sources with femtosecond pulses and full coherence.

Synthesis of an amphiphilic PEG-PCL-PSt-PLLA-PAA star quintopolymer and its self-assembly for pH-sensitive drug delivery

A novel amphiphilic ABCDE-type star quintopolymer was achieved via modular synthesis and self-assembled into polymersomes for stimuli-triggered drug release.

Complex Self-Assembled Morphologies of Thin Films of an Asymmetric A3B3C3 Star Polymer

An asymmetric nine-arm star polymer, (polystyrene)₃-(poly(4-methoxystyrene))₃-(polyisoprene)₃ (PS₃-PMOS₃-PI₃) was synthesized, and the details of the structures of its thin films were successfully investigated for the first time by using in situ grazing incidence X-ray scattering (GIXS) with a synchrotron radiation source. Our quantitative GIXS analysis showed that thin films of the star polymer molecules have very complex but highly ordered and preferentially in-plane oriented hexagonal (HEX) structures consisting of truncated PS cylinders and PMOS triangular prisms in a PI matrix. This HEX structure undergoes a partial rotational transformation process at temperatures above 190 °C that produces a 30°-rotated HEX structure; this structural isomer forms with a volume fraction of 23% during heating up to 220 °C and persists during subsequent cooling. These interesting and complex self-assembled nanostructures are discussed in terms of phase separation, arm number, volume ratio, and confinement effects.