Microwave-assisted synthesis and micellization behavior of soy-based copoly(2-oxazoline)s

Abstract

Polymers based on renewable resources are promising candidates for replacing common organic polymers, and thus, for reducing oil consumption. In this contribution we report the microwave-assisted synthesis of block and statistical copolymers from 2-ethyl-2-oxazoline and 2-“soy alkyl”-2-oxazoline via a cationic ring-opening polymerization mechanism. The synthesized copolymers were characterized by gel permeation chromatography and 1H-NMR spectroscopy. The micellization of these amphiphilic copolymers was investigated by dynamic light scattering and atomic force microscopy to examine the effect of hydrophobic block length and monomer distribution on the resulting micellar characteristics.

Poly(2‐oxazoline)s based on fatty acids

“…After annealing a broad plateau region was observed form 20 to 100 wt% SoyOx with a surface energy around 30, which was ascribed to a combination of preferential orientation of the side chains and the presence of hydrophilic ether and peroxy groups resulting from oxidative UV-crosslinking. The synthesis and aqueous micellization of a poly(EtOxb-SoyOx) block copolymer was reported by Schubert and Gohy [85,86]. UV-irradiation of the micellar solution resulted in the formation of core-crosslinked micelles based on oxidative coupling of the unsaturated sites of poly(SoyOx).…”

Poly(2‐oxazoline)s: Alive and Kicking

“…[60] This successful micellization of the statistical copolymer is most likely facilitated by the clustered distribution of the monomers throughout the polymer chains as indicated by the reactivity ratios.…”

Poly(2‐oxazoline)s as Polymer Therapeutics

“…Importantly, amphiphilic POx of sufficient amphiphilic contrast self-assemble into defined and small, usually spherical micellar aggregates as analyzed by dynamic light scattering (DLS), fluorescence correlation spectroscopy (FCS) and SANS for PNOx-PMeOx, -PEtOx and -iPrOx as well as -nPrOx block copolymers, [26], [34], [49]– [51] or by AFM on surface deposited micelles for PMeOx/PEtOx with soy-based 2-oxazolines (SoyOx), PhOx and NOx. [52]–[57] The living ring-opening copolymerization of 2-oxazolines even allows for the synthesis of defined tetrablock POx. [53] For the design of micelles for drug-delivery, amphiphilic gradient copolymers provide an interesting alternative, as the solubility of gradient and block copolymers differ substantially, [58] the resulting aggregate structures are significantly different, [50] the surface activity of gradient copolymers is much higher [59] which considerably modulate the drug encapsulation efficiency, [60] the cell uptake [61] and possibly trafficking of drug loaded micelles.…”