How to Modulate the Chemical Structure of Polyoxazolines by Appropriate Functionalization

Abstract

Polyoxazolines (POx) are increasingly studied as polymeric building blocks due to the possibility of affording tunable properties. Additionally, as it was proved that biocompatibility and stealth behavior of POx are similar to that of poly(ethylene glycol) (PEG), it became challenging to develop polyoxazoline-based (co)polymers. Even if POx have a lot of advantages, they also show an important drawback as it is to date impossible to prepare high molecular weight polyoxazolines, with low polydispersity indexes. So, it appears important to judiciously functionalize them. This review covers the multiple ways of functionalization of polyoxazolines.The use of functional initiators, functional terminating agents, and 2-R-2-oxazolines with R functional side group is detailed. In conclusion, some perspectives on POxfunctionalizations are also reported, with functions permitting selective "click" reactions.

Thermal Properties of Methyl Ester-Containing Poly(2-oxazoline)s

“…Functional groups, often protected, can be introduced into PAOx by making use of a functional monomer or initiator during the living cationic ring opening polymerisation (CROP, Scheme 1) of 2-oxazoline monomers or by using a functional terminating agent, yielding well-defined PAOx with control over number and type of functionalities [15,[29][30][31][32][33][34][35][36][37][38]. Methyl esters are especially interesting, because they can undergo a direct amidation with a variety of amines to easily introduce other functional groups such as alcohols, hydrazide and amines [39][40][41][42].…”

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

“…The most recent developments published in the last ten years have been focused on during the compilation of this review; crosslinked poly(2-oxazoline)s, which were reviewed in a recent publication, have been omitted from this compilation [10]. While this review focuses on the synthesis of poly(2-oxazoline)s and copoly(2-oxazoline)s as well as the derived materials, the properties of the polymers and materials themselves will be discussed only for dedicated examples, and the reader interested in more and/or more general details is referred to recent reviews in that area [11][12][13][14][15][16][17][18][19][20].…”

In-vitro cytotoxic activities of poly(2-ethyl-2-oxazoline)-based amphiphilic block copolymers prepared by CuAAC click chemistry

“…Among them, poly(2-oxazoline)s with short side chains (ethyl, nand iso-propyl), except for 2-methyl-2-oxazoline, permit easy access to amphiphilic and well-defined block copolymers owing to the lower critical solution temperature (LCST) behavior in aqueous solutions and thermoresponsive properties [35][36][37][38][39]. To date, poly(2-oxazoline)s are obtained utilizing various initiators including halides such as benzyl bromide, alkyl esters such as methyl tosylate, methyl triflate and Lewis acids such as boron trifluoride (BF 3 -OEt 2 ) [40][41][42]. Moreover, poly(2-oxazoline)s are functionalized with many terminating agents such as water, hydroxyl ion in methanolic sodium hydroxide solution, ammonia, piperidine, sodium azide etc [43][44][45][46][47].…”