46 research outputs found

    A triple carboxylic acid-functionalized RAFT agent platform for the elaboration of well-defined telechelic 3-arm star PDMAc

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    This communication describes the synthesis of a triple acid-functionalized RAFT agent and its use to prepare well-defined 3-arm star polymers of N,N-dimethylacrylamide (DMAc). A simple esterification reaction allowed the convenient integration of three electron-rich naphthalene recognition units on the RAFT agent platform and subsequently the elaboration of a naphthalene end-decorated telechelic 3-arm star PDMAc. This functionalized star polymer was further exploited to build a hydrogel with a complementary homoditopic host unit featuring tetracationic macrocycle cyclobis(paraquat-p-phenylene) units

    Chain transfer kinetics of acid/base switchable n-aryl- n-pyridyl dithiocarbamate RAFT agents in methyl acrylate, n-vinylcarbazole and vinyl acetate polymerization

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    This is an accepted manuscript of an article published by American Chemistry Society in Macromolecules on 14/05/2012, available online: https://doi.org/10.1021/ma300616g ©American Chemical Society. The accepted version of the publication may differ from the final published version.The structures of the "Z" and "R" substituents of a RAFT agent (Z-C(S)S-R) determine a RAFT agent's ability to control radical polymerization. In this paper we report new acid/base switchable N-aryl-N-pyridyl dithiocarbamates (R = -CH 2CN, Z = -N(Py)(Ar)) which vary in substituent at the 4-position of the aryl ring and the use of these to control molecular weight and dispersity. In their protonated form, the new RAFT agents are more effective in controlling polymerization of the more activated monomer, methyl acrylate (MA), whereas in their neutral form they provide more effective control of the polymerization of less activated monomers, N-vinyl carbazole (NVC) and vinyl acetate (VAc). For each polymerization, the apparent chain transfer coefficient (C trapp) shows a good correlation with Hammett parameters. Dithiocarbamates with more electron-withdrawing aryl ring substituents have the higher C trapp. This demonstrates the influence of polar effects on C trapp and supports the hypothesis that the activity of these RAFT agents is determined by the availability of the lone pair of the dithiocarbamate nitrogen.The authors gratefully acknowledge the Capability Development Fund of CSIRO Materials Science and Engineering for financial support.Published versio

    Side-chain supramolecular polymers employing conformer independent triple hydrogen bonding arrays

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    Derivatives of thymine have been extensively used to promote supramolecular materials assembly. Such derivatives can be synthetically challenging to access and may be susceptible to degradation. The current article uses a conformer-independent acceptor-donor-acceptor array (ureidopyrimidine) which forms moderate affinity interactions with diamidopyridine derivatives to effect supramolecular blend formation between polystyrene and poly(methyl methacrylate) polymers obtained by RAFT which have been functionalized with the hydrogen bonding motifs
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