Poly(2‐oxazoline) Hydrogels: State‐of‐the‐Art and Emerging Applications

Abstract

The synthesis of poly(2-oxazoline)s has been known since the 1960s. In the last two decades, they have risen in popularity thanks to improvements in their synthesis and the realization of their potential in the biomedical field due to their "stealth" properties, stimuli responsiveness, and tailorable properties. Even though the bulk of the research to date has been on linear forms of the polymer, they are also of interest for creating network structures due to the relatively easy introduction of reactive functional groups during synthesis that can be cross-linked under a variety of conditions. This opinion article briefly reviews the history of poly(2-oxazoline)s and examines the in vivo data on soluble poly(2-oxazoline)s to date in an effort to predict how hydrogels may perform as implantable materials. This is followed by an overview of the most recent hydrogel synthesis methods and emerging applications, and is concluded with a section on the future directions predicted for these fascinating yet underutilized polymers.

Utilization of 4‐(trifluoromethyl)benzenesulfonates as Counter Ions Tunes the Initiator Efficiency of Sophisticated Initiators for the Preparation of Well‐Defined poly(2‐oxazoline)s

“…Since the initial reports of the cationic ring-opening polymerization (CROP) during the 1960s by four different research groups, [1][2][3][4] the interest regarding the development of 2-oxazolines as well as the corresponding poly(2-oxazoline)s (POx) has increased rapidly. [5][6][7][8][9] In particular since 2004, when F. Wiesbrock et al first used microwave irradiation for the polymerization of 2-oxazolines, whereby the reaction times could be significantly decreased, [10] the interest in this versatile polymer class significantly increased. Since then, research focuses on tuning the properties of these extraordinary polymers by the introduction of functionalities, which can be done by i) the aid of a functional initiator or (ii) a termination agent, as well as (iii) by modification of the monomers' 2-position to yield a wide range of side-chain functionalities.…”

“…Since the initial reports of the cationic ring‐opening polymerization (CROP) during the 1960s by four different research groups, the interest regarding the development of 2‐oxazolines as well as the corresponding poly(2‐oxazoline)s (POx) has increased rapidly . In particular since 2004, when F. Wiesbrock et al first used microwave irradiation for the polymerization of 2‐oxazolines, whereby the reaction times could be significantly decreased, the interest in this versatile polymer class significantly increased.…”

Acyl guanidine functional poly(2‐oxazoline)s as reactive intermediates and stimuli‐responsive materials

“…Poly(2‐alkyl/aryl‐2‐oxazoline)s (PAOx's) are a polymer class possessing a large structural versatility, allowing straightforward tuning of the polymer properties and functionality . This appealing feature and their excellent physicochemical stability in combination with biocompatibility have led to their rising popularity as a biomedical material, for example, polymer–drug conjugates, tissue engineering, matrix excipient, and controlled drug release . Within most of these applications, postpolymerization modification reactions play a central role in the synthesis of functional polymers, enabling to overcome the limitations of the cationic ring‐opening polymerization (CROP).…”

Polyoxazoline associated with cardanol for bio‐based linear alkyl benzene surfactants

“…88). They find applications in various areas such as hydrogels, surface modifications, the health field, and surfactants . Their use as a surfactant was reported for the first time by Kobayashi et al .…”

“…They find applications in various areas such as hydrogels, surface modifications, the health field, and surfactants. [31][32][33][34][35][36][37][38] Their use as a surfactant was reported for the first time by Kobayashi et al who designed copolymers containing both hydrophilic and lipophilic POx blocks. 39 More recently, POx blocks have been linked to bio-based blocks such as glycopolymers and fatty derivatives or to petro-based blocks including polysiloxanes, aliphatic polyesters and fluorinated chains, giving various amphiphilic copolymers with surfactant or self-assembling properties.…”