High-Efficiency Preparation of Macrocyclic Diblock Copolymers via Selective Click Reaction in Micellar Media

Abstract

We report a novel strategy for the high-efficiency preparation of macrocyclic diblock copolymers at relatively high concentrations via the combination of supramolecular self-assembly and "selective" click reactions, relying on the fine control of spatial accessibility between terminal reactive groups. The linear precursor, alpha-alkynyl-omega-azido heterodifunctional poly(2-(2-methoxyethoxy)ethyl methacrylate)-b-poly(oligo(ethylene glycol) methyl ether methacrylate), linear-PMEO(2)MA-b-POEGMA-N(3), self-assembles into micelles with PMEO(2)MA cores and POEGMA coronas at elevated temperatures. The spatial separation between reactive alkynyl and azide groups precludes click reactions within micelle entities. On the other hand, due to the unimer-micelle exchange equilibrium and the fact that unimer concentration is typically low (critical micellization concentration, CMC), click reactions occur exclusively for unimers. This eventually led to complete intramolecular cyclization of all linear precursors.

Facile Synthesis of Glycopolypeptides by Combination of Ring‐Opening Polymerization of an Alkyne‐Substituted N‐carboxyanhydride and Click “Glycosylation”

“…In addition, the characteristic signal at 8.0 ppm attributed to resonance of the proton c of the triazole ring and methylene proton b signal shifted from 4.8 ppm in the polypeptides 3 to 5.1 ppm in the glycopolypeptides, indicating the click formation of triazole. [20] Therefore, both FT-IR and 1 H NMR results confirmed the effective clicking of sugars leading to glycopolypeptides. The molecular weight obtained from GPC results ( Figure S2) were increased correspondingly after conjugating with the sugars.…”

Thermo‐Switchable Materials Prepared Using the OEGMA‐Platform

“…[ 65 ] Alternatively, double hydrophilic block copolymers containing a permanently hydrophilic segment and a thermoresponsive POEGMA segment have been also described. [66][67][68][69] These macromolecules are fully soluble in water below LCST but micellize at higher temperatures due to the aqueous precipitation of the POEGMA blocks. For example, Hammond and co-workers used this concept to assemble/disassemble dendritic elements in aqueous medium.…”

Synthesis of Amphiphilic Tadpole-Shaped Linear-Cyclic Diblock Copolymers via Ring-Opening Polymerization Directly Initiating from Cyclic Precursors and Their Application as Drug Nanocarriers

“…[1][2][3] It has been well-established that the topological structures and chemical composition of nonlinearshaped block copolymers can exhibit dramatic effects on the solution properties and self-assembling morphologies as compared with their linear counterpart. [4][5][6][7][8][9] It is worthy of noting that the developments of a variety of controlled radical polymerization techniques 10 such as atom transfer radical polymerization (ATRP), [11][12][13] reversible addition-fragmentation chain transfer (RAFT) polymerization, [14][15][16] and nitroxide-mediated polymerization (NMP) 17,18 have facilitated the synthesis of nonlinear-shaped polymers with varying chain architectures such as cyclic, 8,9,[19][20][21][22][23] (miktoarm) star, [24][25][26] star block copolymers, 27,28 comb, [29][30][31][32] sun-shaped, [33][34][35] H-shaped, [36][37][38] and θ-shaped 39,40 polymers. Among these nonlinear chain topologies, tadpole-shaped linearcyclic diblock copolymers [41]…”