Lysine-based polypeptides can be afforded with steerable secondary structures and tunable thermoresponsiveness through dynamic covalent OEGylation. These polypeptides were formed through dynamic imine linkage via reactions of amino moieties from poly(l-lysine)s with aldehydes from oligoethylene glycol (OEG)-based dendrons. In addition to solution concentrations and pH values, macromolecular effect was found to play an important role on the imine formation. OEGylated polypeptides showed characteristic thermoresponsive properties, and their phase transition temperatures were governed predominately by terminal groups and the coverage of OEG dendrons. Notably, thermally induced aggregation would enhance the imine formation even at elevated temperature. In contrast to the covalent polypeptide representatives, the dynamic covalent polypeptides conveyed different thermoresponsiveness due to imine linkages, and their phase transition temperatures could be tuned simply by varying ratios of OEG dendrons with different hydrophilicity. Furthermore, helical conformation of these polypeptides was enhanced with attachment of OEG dendrons, and could be reversibly switched through thermally induced aggregation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 33–41

The first (G1) and second generation (G2) of dendronized copolymers carrying solvatochromic dyes were synthesized, and their thermoresponsive properties investigated. These copolymers were constituted with oligoethylene glycol (OEG)-based dendrons to afford the thermoresponsiveness and disperse red 1 to act as the dye probe. The possible architecture and structure effects on sensoring were investigated by changing dendron generation from G1 to G2, and the interior structures of G2 polymers from hydrophilic OEG into hydrophobic alkyl chain. The sensoring ability of these copolymers to temperature and solution pH was examined with UV/Vis spectroscopy. Combined with the supports from fluorescence spectroscopy, remarkable thickness effects of dendronized polymers were discovered on the transitions of the dye moieties during the thermally-induced aggregation process. This work enriches the field of thermoresponsive colorimetric polymeric sensors, and provides an in-depth understanding of state changes of the dye probe during the thermally-induced phase transitions within these bulky dendronized polymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1706–1713

The dendronization of linear polymers by dendrons with different cores and peripheries provides a convenient strategy to fuse distinct properties in one matter. By combining thermoresponsive properties with chirality, a series of doubly dendronized polymers possessing interior chiral proline units and peripheral oligoethylene glycol (OEG)-based dendrons are synthesized and characterized. The chirality of proline moieties are varied to check potential effects on thermoresponsiveness and chiroptical properties, and the terminal groups in the OEG periphery are changed to tune the hydrophilicity of the resulting polymers. The macromonomer route is applied to obtain polymers with well-defined structures. Free radical polymerization in bulk results in polymers with surprisingly high molar masses. Their thermally induced phase transition processes are monitored by UV–vis spectroscopy, and chiroptical properties are monitored by optical rotation measurements and circular dichroism spectroscopy. These doubly dendronized polymers show characteristic thermoresponsive behavior, and their phase transition temperatures are dominated by the peripheral structures. Polymerization accompanies weak chiral amplification, but the chirality of the proline interior contributes significantly to the thermal stability of chiroptical properties of the resulting polymers. In vitro cytotoxicity measurements are carried out to check the biocompatibility of these thermoresponsive polymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5143–5152