Characterization of poly(2-oxazoline) homo- and copolymers by liquid chromatography at critical conditions

In this study liquid chromatography at critical conditions for poly(2-ethyl-2-oxazoline)s (PEtOx) has been performed for the first time in order to analyze functional PEtOx homopolymers and block copolymers. Besides the verification of the critical point of adsorption with two series of ester end group functionalized PEtOx homopolymers, to evaluate the effect of both the chain length dependence and the end group polarity, using a cyano column with a solvent combination of 2-propanol and water, also two-dimensional liquid chromatography (2D-LC) has been applied for a poly(2-oxazoline) block copolymer. The combined characterization techniques provided further information about the polymerization procedure with regard to the formation of side-products by separation of the block copolymer from the corresponding homopolymer impurities. In addition, hyphenation of LCCC with MALDI-TOF MS and ESI-Q-TOF tandem mass spectrometry verified the obtained results.

► Liquid chromatography at the critical conditions for poly(2-ethyl-2-oxazoline)s (PEtOx) has been performed for the first time to analyze functional PEtOx homopolymers and block copolymers.
► Verification of the critical point of adsorption has been performed with two series of ester end group functionalized PEtOx homopolymers.
► In addition, two-dimensional chromatography (2D-LC) and hyphenation of LCCC with different mass spectrometry techniques have been applied for a poly(2-oxazoline) block copolymer to gain more information about the polymerization procedure with regard to the formation of side-products.