Comblike Thermoresponsive Polymers with Sharp Transitions: Synthesis, Characterization, and Their Use as Sensitive Colorimetric Sensors

Abstract

The synthesis and thermoresponsive behavior of two structural novel comblike polymers are presented, which are constituted by polymethacrylates main chain with dendritic oligoethylene glycol (OEG) side groups spaced with a linear hydrophobic alkyl [PG1(A)] or hydrophilic OEG unit [PG1(G)]. The design of this comblike architecture is to retain the unique thermoresponsive behavior of OEG-based dendritic polymers and, on the other side, to eliminate the tremendous synthesis effort for the dendronized polymer analogues. Their thermoresponsive behavior was investigated with UV/vis and temperature-varied 1H NMR spectroscopy to determine their apparent LCSTs and follow chain dehydration process, respectively. These polymers show sharp and fast transitions with small hystereses. The phase transition temperatures are located in between 27 and 34 °C, which is in the vicinity of physiological temperature, and these transition temperatures are independent of polymer concentration. The thermoresponsiveness of these po...