Tuning the LCST of poly(2-oxazoline)s by varying composition and molecular weight: alternatives to poly(N-isopropylacrylamide)?

摘要

The cloud point of copolymers of 2-ethyl-2-oxazoline and 2-n-propyl-2-oxazoline could be tuned from 25 ℃ to 100 ℃ by varying molecular weight and composition; the reversibility and concentration dependence of the cloud points were evaluated to assess the potential of these copoly(2-oxazoline)s as alternatives to poly(N-isopropylacrylamide).rnThermoresponsive polymers that undergo a solubility transition upon changes in temperature are an interesting class of polymers for a variety of applications ranging from drug delivery to bioengineering and from responsive magnetic particles to separation processes. The most widely studied thermoresponsive polymer is poly(N-isopropylacrylamide) (PNIPAM) based on its lower critical solution temperature (LCST) of ～ 32 ℃ which is close to body temperature as well as the relatively small dependence of the LCST on changes in concentration, pH or ionic strength.