Facile synthesis of ABCDE‐type H‐shaped quintopolymers by combination of ATRP, ROP, and click chemistry and their potential applications as drug carriers

Polylactic-Containing Hyperbranched Polymers through the CuAAC Polymerization of Aromatic AB2 Monomers

We report on the synthesis and characterization of a novel class of hyperbranched polymers, in which a copper(I)-catalyzed alkyne azide cycloaddition (CuAAC) reaction (the prototypical "click" reaction) is used as the polymerization step. The AB₂ monomers bear two azide functionalities and one alkyne functionality, which have been installed onto a 1,3,5 trisubstituted benzene aromatic skeleton. This synthesis has been optimized in terms of its purification strategies, with an eye on its scalability for the potential industrial applications of hyperbranched polymers as viscosity modifiers. By taking advantage of the modularity of the synthesis, we have been able to install short polylactic acid fragments as the spacing units between the complementary reactive azide and alkyne functionalities, aiming to introduce elements of biodegradability into the final products. The hyperbranched polymers have been obtained with good molecular weights and degrees of polymerization and branching, testifying to the effectiveness of the synthetic design. Simple experiments on glass surfaces have highlighted the possibility of conducting the polymerizations and the formation of the hyperbranched polymers directly in thin films at room temperature.

End-functionalized polymers by controlled/living radical polymerizations: synthesis and applications

This review focuses on end-functionalized polymers synthesized by controlled/living radical polymerizations and the applications in fields including bioconjugate formation, surface modification, topology construction, and self-assembly.

High impact polytriazole resins for advanced composites

Three azido-terminated poly(ethylene glycol) macromonomers (ATPEGs) were synthesized from poly(ethylene glycol)s (PEGs) and characterized. The extended polytriazole (EPTA) resins were prepared from the macromonomers, azide and alkyne monomers. Toughening effect of PEGs on polytriazole resins was analyzed by means of mechanical, thermal and electronic microscope characterization. The results show that molecular weight and content of ATPEGs have great influence on the thermal and mechanical properties of cured EPTA resins. The impact strength of cured EPTA resins increases with the increase of the amount and molecular weight of ATPEGs. The flexural strength and heat resistance of cured EPTA resins decrease with the increase of addition amount and molecular weight of ATPEGs. High impact EPTA resins were obtained.

Orthogonally functionalizable polyacetals: a versatile platform for the design of acid sensitive amphiphilic copolymers

Dually functionalized amphiphilic copolyacetals as rational approach to the development of pH-responsive site-specific drug delivery systems.

PAA-g-PLA amphiphilic graft copolymer: synthesis, self-assembly, and drug loading ability

This article reports the synthesis of a PAA-g-PLA amphiphilic polymer by the combination of RAFT polymerization and organocatalytic ROP, which could self-assemble into spheres in aqueous media for sustained release of doxorubicin.

Synthesis of an amphiphilic graft copolymer bearing a hydrophilic poly(acrylate acid) backbone for drug delivery of methotrexate

This article reports the synthesis of a PAA-g-PLA amphiphilic graft polymer, which could self-assemble into large compound micelles in aqueous media for sustained release of MTX.

Synthesis and Star/Linear Topology Transformation of a Mechanically Linked ABC Terpolymer

The synthesis of an ABC star terpolymer containing one polymer chain connected mechanically through a rotaxane linkage and its topology transformation to a linear structure are reported. Pseudo[2]rotaxane, which was designed as the key trifunctional species for the star polymer synthesis, comprised a sec-ammonium axle with ethynyl and hydroxy groups and a crown ether wheel with a trithiocarbonate group. Stepwise polymer connections to the pseudo[2]rotaxane using the three groups afforded a rotaxane-linked ABC star terpolymer. The topology transformation from star to linear by the removal of the attractive interaction between the axle and wheel components yielded a linear ABC terpolymer via the wheel shifting to the axle end. The spectroscopic and solution property changes clearly indicated the occurrence of the polymer topology change.

Construction of PEG-based amphiphilic brush polymers bearing hydrophobic poly(lactic acid) side chains via successive RAFT polymerization and ROP

This article reports the synthesis of PEG-b-(PAA-g-PLA) amphiphilic brush polymers by the combination of RAFT polymerization and organocatalytic ROP, which could self-assemble into spheres for sustained release of doxorubicin.

Mechanically Linked Block/Graft Copolymers: Effective Synthesis via Functional Macromolecular [2]Rotaxanes

An effective method to synthesize mechanically linked transformable block polymer was developed utilizing functional macromolecular [2]rotaxane with a "fixed" or "movable" wheel. The interaction between a sec-ammonium and a dibenzo-24-crown-8-ether was the key to control the mobility of the wheel component, indicating the capability of the transformation from linear block copolymer to block/graft copolymer in which the grafting polymer chain is movable along the axle polymer chain.

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.

Facile Preparation of Supramolecular H-Shaped (Ter)polymers via Multiple Hydrogen Bonding

A well-defined Hamilton wedge (HW) midchain functionalized block copolymer, i.e., polyethylene glycol-b-polystyrene (PEG-HW-PS, M_n,GPC = 5600 Da, PDI = 1.03), was successfully synthesized via a combination of atom transfer radical polymerization (ATRP) and copper-catalyzed azide alkyne cycloaddition (CuAAC). An α,ω-cyanuric acid (CA) difunctional linear homopolymer poly(n-butylacrylate) (CA-PnBA-CA, M_n,GPC = 8100 Da, PDI = 1.09) was concomitantly prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. Supramolecular H-shaped macromolecules were-for the first time-prepared through supramolecular self-assembly between HW and CA recognition motifs to generate (PS-b-PEG)·PnBA·(PS-b-PEG) and (PS-b-PS)·PnBA·(PS-b-PS) in CH₂Cl₂ or dichloromethane-d₂ at ambient temperature. The self-assembly process (at a total concentration of the two species of close to 4.5 mM) was evidenced by proton nuclear magnetic resonance (¹H NMR) spectroscopy, diffusion-ordered NMR spectroscopy (DOSY), and dynamic light scattering (DLS) analyses. The results derived via DOSY NMR experiments and DLS combined with a Job plot analysis and in-depth NMR titration experiments indicate that the formation of supramolecular H-shaped macromolecules in 2:1 stoichiometry is efficiently occurring via the employed complementary recognition motifs with high binding constants (between 1.2 and 1.5 × 10⁵ L mol^-1 at ambient temperature).