Unexpected Aqueous UCST Behavior of a Cationic Comb Polymer with Pentaarginine Side Chains

Publication date: Available online 20 January 2020Source: European Polymer JournalAuthor(s): Nicolas Zydziak, Muhammad Haseeb Iqbal, Alain Chaumont, Antoine Combes, Emeric Wasielewski, Mélanie Legros, Loïc Jierry, Philippe Lavalle, Fouzia Boulmedais, Delphine Chan-SengAbstractThermoresponsive polymers, undergoing a reversible chemical or physical change using temperature as stimulus, attract increasing interest in particular as adaptable biomaterials. Except for zwitterionic polymers, fully charged polymers require the presence of specific ions to exhibit an upper critical solution temperature (UCST) in water. Herein, we report the discovery of an UCST in pure water for fully cationic comb polymers based on oligoarginine pendent grafts. These polymers were prepared using an original strategy based on solid-phase peptide synthesis of pentaarginine methacrylate-based macromonomer and its polymerization through reversible addition-fragmentation chain transfer. Despite their cationic nature, guanidinium groups from the arginine have the ability to self-associate at low temperature through hydrophobic interactions into stacked pair configuration defying the expected Coulomb interactions. These results pave the way to biomedical applications such as antimicrobial materials and drug delivery systems through the tuning of the polymer structure.Graphical abstract

Source: European Polymer Journal - January 21, 2020 Category: Chemistry Source Type: research