Self-assembly behavior of oligo(ethylene glycol) substituted polycaprolactone homopolymers

Abstract

Amphiphilic homopolymers are gaining importance due to their easy synthesis compared to copolymers and their ability to assemble into various nanostructures. The majority of reported amphiphilic homopolymers have a non-biodegradable backbone, are charged, and are dependent on pH for assembly. In this work, we report the self-assembly behavior of non-ionic amphiphilic poly(γ-oligo(ethylene glycol)-ε-caprolactone) homopolymers (PME_xCL, x = 2, 3, and 4), and a novel poly(N-dodecyl-N-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-7-oxoxepane-4-carboxamide (PME₃DDCL) homopolymer. These synthesized amphiphilic homopolymers readily self-assembled forming micelles in a polar environment. PME_xCL also exhibited thermoresponsivity; hence, several parameters that affect the thermoresponsivity of these polymers were studied, such as degree of polymerization, concentration, heating rate, and length of oligo(ethylene glycol) side chains. The size, morphology, and thermodynamic stability were investigated, and the micelles were loaded with eugenol to explore the possibility of using the micelles for drug encapsulation. These self-assembled homopolymers hold promise for vast applications, particularly in the biomedical field.