Jump to main content
Jump to site search

Issue 7, 2011
Previous Article Next Article

Study of poly(N,N-diethylacrylamide) nanogel formation by aqueous dispersion polymerization of N,N-diethylacrylamide in the presence of poly(ethylene oxide)-b-poly(N,N-dimethylacrylamide) amphiphilic macromolecular RAFT agents

Author affiliations

Abstract

The formation of thermoresponsive poly(N,N-diethylacrylamide) (PDEAAm) nanogels via an aqueous dispersion polymerization process in the presence of poly(ethylene oxide)-b-poly(N,N-dimethylacrylamide) macromolecular reversible addition–fragmentation chain transfer agents (macroRAFT agents) was studied. The latter exhibit a hydrophobic trithiocarbonate reactive group with a dodecyl substituent, and had previously proved to act simultaneously as control agents and stabilizers in such a synthesis process (Rieger et al., J. Polym. Sci. Part A: Polym. Chem., 2009, 47, 2373). The nanogel size and stability were found to depend strongly on the chain length of the macroRAFT agents, but also on the crosslinker (N,N′-methylene bisacrylamide) and monomer concentrations. The aim of the present work was to better understand the mechanisms that govern the nanogel formation in such heterogeneous polymerization conditions performed under RAFT control, with special emphasis on the role of the macroRAFT agents. In the first part, the aqueous solution properties of the macroRAFT agents in the conditions of the dispersion polymerizations were studied by light scattering and fluorescence spectroscopy and it was found that they self-assemble to form star micelles. In the second part, the nanogel formation at different DEAAm and crosslinker concentrations was monitored by dynamic and static light scattering, and by size exclusion chromatography. It appeared that at low monomer conversion the calculated number of chains per nanogel particle was close to the aggregation number, Nagg, of the macroRAFT agent micelles. With increasing conversions, however, the number of chains clearly increased and exceeded the initial Nagg. Higher monomer concentrations hardly influenced the formation process and thus the gel particle size, whereas enhanced crosslinker concentration had a strong impact on the latter. These results strongly suggest that precursor particles are formed very rapidly at the polymerization onset and then aggregate with each other to form complex inter-crosslinked particles.

Graphical abstract: Study of poly(N,N-diethylacrylamide) nanogel formation by aqueous dispersion polymerization of N,N-diethylacrylamide in the presence of poly(ethylene oxide)-b-poly(N,N-dimethylacrylamide) amphiphilic macromolecular RAFT agents

Back to tab navigation

Supplementary files

Article information


Submitted
21 Oct 2010
Accepted
12 Jan 2011
First published
14 Feb 2011

Soft Matter, 2011,7, 3482-3490
Article type
Paper

Study of poly(N,N-diethylacrylamide) nanogel formation by aqueous dispersion polymerization of N,N-diethylacrylamide in the presence of poly(ethylene oxide)-b-poly(N,N-dimethylacrylamide) amphiphilic macromolecular RAFT agents

C. Grazon, J. Rieger, N. Sanson and B. Charleux, Soft Matter, 2011, 7, 3482
DOI: 10.1039/C0SM01181A

Social activity

Search articles by author

Spotlight

Advertisements