Temperature-Responsive Polymers

Chapter 3Star‐shaped Poly(2‐alkyl‐2‐oxazolines): Synthesis and Properties

Andrey V. Tenkovtsev Alina I. Amirova and Alexander P. Filippov

Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 Saint Petersburg, Russia

3.1 Introduction

During the recent decades, stimuli‐responsive polymers have become ever more interesting objects for study due to the wide range of applications and ways for their modification [1–4]. The key feature of these polymers is the change in their properties that is caused by very weak variation of environmental conditions. In the case of water‐soluble thermo‐ and pH‐sensitive polymers, the response is provided by the change in temperature, pH, ionic strength, chemical structure of functional dopants, etc. It is the result of rearrangements that take place on molecular and supramolecular levels.

Special attention is given to the thermosensitive polymers with low critical solution temperature (LCST) close to the body temperature. They are widely used as sensors, rheological additives, and multiple biological applications, including drug delivery. An example of this class of thermosensitive macromolecular systems are poly(2‐alkyl‐2‐oxazolines), which are structural isomers of polypeptides and are often considered as bioinspired polymers or pseudopeptides [5–7]. The LCST transition of poly(2‐alkyl‐2‐oxazolines) is caused by the phenomena that take place at monomer unit level, namely, by the hydrophilic–hydrophobic balance changes with temperature. ...