Switchable Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization in Aqueous Solution, N,N-Dimethylacrylamide

Author(s)
Keddie, Daniel
Guerrero-Sanchez, Carlos
Moad, Graeme
Rizzardo, Ezio
Thang, San H
Publication Date
2011
Abstract
Reversible addition-fragmentation chain transfer (RAFT) polymerization of a 'more activated monomer' (MAM), N,N-dimethylacrylamide (DMAm), has been successfully achieved in aqueous solution using an acid/base switchable pyridyl-substituted dithiocarbamate RAFT agent. The effect of strength (pKa) and stoichiometry of the acid used to switch the RAFT agent on the molecular weight and dispersity of poly(N,N-dimethylacrylamide) (PDMAm) were examined, making use of high-throughput protocol. Best control was achieved with a stoichiometric amount of the strongest acid investigated, p-toluenesulfonic acid monohydrate. Use of weaker acids (higher pKa) or less than stoichiometric amounts of acid with respect to RAFT agent resulted in broader molecular weight distributions. These results can be rationalized in terms of the extent of protonation of the pyridine nitrogen of the RAFT agent (pKa~3.13). The preparation of unimodal low dispersity block copolymers of PDMA with the 'less-activated' monomers (LAMs) N-vinylcarbazole (NVC), vinyl acetate (VAc), and N-vinylpyrrolidone (NVP) demonstrated the fidelity of the RAFT end group in these experiments and provides a further example of the utility of switchable RAFT polymerization.
Citation
Macromolecules, 44(17), p. 6738-6745
ISSN
1520-5835
0024-9297
Link
Publisher
American Chemical Society
Title
Switchable Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization in Aqueous Solution, N,N-Dimethylacrylamide
Type of document
Journal Article
Entity Type
Publication

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