Synthesis of well-defined poly(2-(dimethylamino)ethyl methacrylate) under mild conditions and its co-polymers with cholesterol and PEG using Fe(0)/Cu(ii) based SARA ATRP

Abstract

Atom transfer radical polymerization (ATRP) of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with a mixed transition metal catalytic system consisting of Fe(0) and small amounts of CuBr₂/PMDETA (N,N,N′,N′′,N′′-pentamethyldiethylenetriamine) in water–isopropanol mixtures at 60 °C and 25 °C is reported and compared with commonly used CuBr/PMDETA-mediated ATRP systems. The obtained kinetics of polymerization showed that, in addition to the environmental attractiveness of this catalytic system, Fe/Cu mixed transition metal mediated ATRP of a DMAEMA monomer provides a significantly improved control of polymer chain growth, forming PDMAEMA of low dispersity values at all conversions. The controlled character of ATRP of DMAEMA was confirmed by the linear increase of molecular weights with monomer conversion, narrow molecular weight distributions, and re-initiation/chain extension experiments. The molecular structure of the obtained polymer(s) was confirmed by ¹H nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy. ATRP of DMAEMA was also extended to synthesis of functional bio-relevant polymers with cholesterol and poly(ethylene glycol) segments.