Exploring the Effect of Amphiphilic Polymer Architecture: Synthesis, Characterization, and Self-Assembly of Both Cyclic and Linear Poly(ethylene gylcol)-b-polycaprolactone

Abstract

While amphiphilic block copolymers have demonstrated their utility for a range of practical applications, the behavior of cyclic block copolymers remains largely unexplored due to limited synthetic access. To investigate their micelle formation, biocompatible cyclic amphiphilic poly(ethylene glycol)-polycaprolactone, c-(PEG-PCL), was synthesized by a combination of ring-opening polymerization (ROP) and click chemistry. In addition, exactly analogous linear block copolymers have been prepared as a control sample to elucidate the role of polymer architecture in their self-assembly and acid-catalyzed degradation.

High-efficiency synthesis of well-defined cyclic poly(N-vinylcaprolactam) and its solution properties

“…The size of micelles formed by c-PNVCL is smaller than that of l-PNVCL-N 3 (25 nm vs 39 nm, respectively). This is consistent with the studies of self-assembly behavior of amphiphilic cyclic copolymers in aqueous solution [5,50] that suggests that the more compact self-assembled units results from the lack of chain ends in the cyclic system [51]. The formation of micelles is also supported by DLS measurement.…”

“…Although new strategies have been proposed recently [12e16], the combination of controlled/living radical polymerization (CRP) and copper catalyzed azideealkyne cycloaddition (CuAAC) click reaction has been the most generally used end-to-end polymer cyclization method. To date, this method has been widely used to prepare a series of well-defined cyclic polymers including polystyrene (PS) [11], poly(N-isopropylacrylamide) (PNIPAM) [17,18], poly(ε-caprolactone) [19], poly(acrylic acid) (PAA) [20], poly(methyl methacrylate) (PMMA) [21], poly(methyl acrylate)-bpolystyrene [22] and poly(ethylene gylcol)-b-polycaprolactone [5]. This unimolecular click process has also been employed to construct complex cyclic structures, such as tadpole-shaped and eight-shaped block copolymers [23e25].…”

Hydrogel formation by the ‘topological conversion’ of cyclic PLA–PEO block copolymers

“…Cyclic polymers have been reported to differ from linear and branching polymers with regards to their physical properties such as viscosity, glass transition temperature, and hydrodynamic volume. 6,7 In recent years, much success has been reported in further developing their functionality, 8 such as improved heat resistance in micelles, 9, 10 the control of micelle particle diameters, 11 and controlling domain intervals. 12 Increasing attention is being paid to such efforts.…”

A study on emulsion stabilization induced with linear and cyclized polystyrene-poly(ethylene oxide) block copolymer surfactants

“…The relevant amphiphilic cyclic and multicyclic block copolymers have been studied by others as well, and unique topology effects have been demonstrated for their selfassemblies in aqueous medium or at the interfaces. [5][6][7][8][9] To gain further insights in the topology effect of the linear and cyclized polymer amphiphiles, we examined the emulsion formation and subsequent phase-separation of water/toluene mixtures. Emulsion stabilization using polymer surfactants is critical in diverse applications such as coating formation, pharmaceutics/cosmetic formulation, food processing, detergent preparation and dyes/pigment production.…”