Synthesis, characterization and micellization of heterograft copolymers based on phosphoester functionalized macromonomers via “grafting through” method

Abstract

Novel amphiphilic heterograft copolymers consisting of phosphoester functionalized PEG (phosPEG) and PCL (phosPCL) were synthesized by the ring-opening polymerization via ''grafting through'' method. The heterograft structure and thermal properties of these copolymers with various compositions were characterized by 1 H-NMR, 31 P NMR, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC) in detail. These amphiphilic copolymers could self-assemble into micellar structures in aqueous solution, and their critical micellization concentrations (CMC) were determined to be 0.69-1.25 mg/L by fluorescence technique. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements show that these heterograft copolymer micelles are spherical in shape with the particle size ranging from 20 to 60 nm, which has potential in biomedical application.

Rapid and Versatile Construction of Diverse and Functional Nanostructures Derived from a Polyphosphoester-Based Biomimetic Block Copolymer System

“…Cyclic phospholane monomers are usually prepared from the condensation of 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP) and an alcohol. A variety of functional cyclic phospholane monomers have been reported, including methyl, 29 ethyl, 30 isopropyl, 31 PEGylated, 32,33 hydroxyl-functionalized, 34,35 protected hydroxyl-functionalized, 36 protected amino-functionalized, 37,38 protected thiolfunctionalized, 39 acrylate-functionalized, 40 methacrylatefunctionalized, 41 alkyne-functionalized 17 and alkenefunctionalized. 27,28 The ring opening polymerization (ROP) of those functional monomers produced corresponding high molecular weight functional polyphosphoesters.…”

“…Cyclic phospholane monomers are usually prepared from the condensation of 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP) and an alcohol. A variety of functional cyclic phospholane monomers have been reported, including methyl, ethyl, isopropyl, PEG-ylated, , hydroxyl-functionalized, , protected hydroxyl-functionalized, protected amino-functionalized, , protected thiol-functionalized, acrylate-functionalized, methacrylate-functionalized, alkyne-functionalized, and alkene-functionalized. , The ROP of those functional monomers produced corresponding high molecular weight functional polyphosphoesters. Our group recently developed a stable alkyne-functionalized cyclic phospholane monomer and studied its polymerization kinetics under an organocatalyst, in addition to the chemical functionalization of this alkyne-functionalized polyphosphoester by click-type azide–alkyne Huisgen cycloaddition and thiol–yne reaction .…”

Synthesis, characterization, and micellization of PCL‐g‐PEG copolymers by combination of ROP and “Click” chemistry via “Graft onto” method

“…All the aggregates exhibit sphere‐like morphologies, and the diameter of the aggregates decrease with the increasing PEG weight fraction, which indicates that copolymers with low‐graft density prefer to form large aggregates because the less PEG branches could not evade the hydrophobic interaction and van der Waals interaction between exposed hydrophobic domains of the micelles. Furthermore, the self‐assembled behavior of PCL‐PEG copolymer is influenced not only by the hydrophobic–hydrophilic weight fraction but also by the macromolecular architecture 16, 43, 45–52. The self‐assembly behavior of PCL‐ b ‐PEG diblock copolymers has been widely studied.…”