Journal of Rheology, Vol.62, No.5, 1233-1243, 2018
Multiple stimuli-responsive rheological behavior of a functionalized telechelic associative model polymer in aqueous solution
Hydrophobically modified telechelic associative polymers (TAPs) composed of hydrophilic backbone and two hydrophobic end groups can form dynamic transient networks in water and have been widely used as thickeners for improving solution rheological properties in many industrial fields. In this work, we designed and prepared a novel telechelic associative model polymer (FcC(11)AzoTAP) end-functionalized by photo-responsive azobenzene (Azo) unit along with the redox-responsive ferrocene extremity, which was used to investigate the effects of stimuli responsive behaviors such as redox reaction or/and photo isomerization of end groups on its solution aggregation and rheological properties. It has been demonstrated that the network structures and rheological properties of FcC(11)AzoTAP aqueous solutions can be readily tuned by the magnitude of stimuli-responsive hydrophobicity change of end groups to a certain degree. Moreover, a rearrangement of network through bridge to inactive loop and/or pending arm transitions is proposed to describe the dense to sparse network conversion. This work will not only provide new insights into the effects of end groups on the network structure and rheological properties of solution but it also opens a new perspective for some special applications of TAPs in industrial fields. (C) 2018 The Society of Rheology.