SP-PLP-EPR Measurement of ATRP Deactivation Rate

Abstract

The ATRP deactivation rate coefficient is measured by applying laser single pulses for radical production in conjunction with subsequent time-resolved detection of the decay of radical concentration. The novel method is illustrated for copper-mediated dodecyl methacrylate (DMA) polymerization with 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as the ligand in the presence of 15 wt % acetonitrile. The experiment consists of two parts: measurement of chain-length-dependent termination on the copper-free monomer system followed by monitoring the decay of propagating radicals after laser pulsing applied to the copper–HMTETA system. The rate coefficient of deactivation by the Cu^II complex is about 2 orders of magnitude below the one of termination of two small propagating DMA-type radicals, which confirms that deactivation is chemically controlled