Title Amphiphilic block copolymers featuring a reversible hetero diels-alder linkage
Date 13.06.2014
Number 43343
Abstract The present article reports the preparation of a novel class of switchable amphiphilic diblock copolymers with a temperature switchable linkage. Reversible addition fragmentation chain transfer (RAFT) polymerization was used to synthesize the individual blocks: for the preparation of the non-polar block, i.e. poly(isoprene-co-styrene) (P(I-co-S)) (9200 g mol-1 = Mn = 50[thin space (1/6-em)]000 g mol-1, 1.22 = Ð = 1.36), a chain transfer agent (CTA, 3-((2-bromo-2-methylpropanoyl)oxy)propyl 2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoate) carrying a bromine group was employed, ready for subsequent cyclopentadienyl (Cp) transformation. For the preparation of the polar block, triethylene glycol methyl ether acrylate (TEGA) was polymerized (6600 g mol-1 = Mn = 35[thin space (1/6-em)]000 g mol-1, 1.12 = Ð = 1.30) using a RAFT agent carrying a phosphoryl Z-group, which is able to undergo hetero Diels-Alder (HDA) ligation with Cp moieties. Both building blocks were conjugated at ambient temperature in the presence of ZnCl2 as catalyst yielding the amphiphilic block copolymer P(I-co-S)-b-PTEGA (16[thin space (1/6-em)]000 g mol-1 = Mn = 68[thin space (1/6-em)]000 g mol-1, 1.15 = Ð = 1.32). To investigate the bonding/debonding capability of the HDA linkage, high temperature nuclear magnetic resonance (HT-NMR) spectroscopy, high temperature dynamic light scattering (HT-DLS) and high temperature size exclusion chromatography (HT-SEC) were carried out, evidencing that efficiently switchable amphiphilic block copolymers were generated (>4 cycles).
Publisher Polymer Chemistry
Citation Polymer Chemistry 5 (2014) 5330-5338
Authors Langer, M. ; Brandt, J. ; Lederer, A. ; Goldmann, A. ; Schacher, F. H. ; Barner-Kowollik, C.

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