The outstanding properties of poly(ethylene glycol) (PEG) like its remarkably water solubility, high chain flexibility and biocompatibility, can be selectively manipulated and expanded by the incorporation of epoxide-based comonomers into the polyether backbone. For example, thermo-responsive PEG derivatives can be synthesized by anionic ring opening polymerization (AROP) of ethylene oxide (EO) and various comonomers, like allyl glycidyl ether (AGE) or isopropylidene glyceryl glycidyl ether (IGG).[1]We present three N,N-dialkyl glycidyl amines (DXGA) as novel building blocks in the AROP with EO: N,N-Dibutyl glycidyl amine (DBuGA), N,N-dihexyl glycidyl amine (DHeGA) and N,N-dioctyl glycidyl amine (DOcGA). Well-defined (Mw/Mn = 1.05-1.13), water-soluble gradient and block copolymers with different comonomer fractions ranging from 4 to 18 mol% can be obtained. The microstructures of these unique copolymers and the relative reactivity of the novel DXGA were elucidated by 1H NMR kinetic studies and 13C NMR triad analysis. 1H NMR, turbidimetry and electron paramagnetic resonance (EPR) studies confirmed that thermo- and pH-responsive behavior of these copolymers is precisely adjustable by the incorporated comonomer ratio and structure. Transition temperatures at human body temperature are easily accessible, without distinctly changing PEG�s unique properties. This feature is essential for future biomedical applications.Figure   1  .  Polymerization strategy for the block and concurrent copolymerization of EO and the respective DXGA.[1] B. Obermeier, F. Wurm, C. Mangold, H. Frey. Angew. Chem. Int. Ed. 2011, 50, 7988�7997.

Tertiary amine-functional poly(ethylene glycols): Thermo- and pH-responsive behavior in aqueous solution

248th National Meeting (2014)

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