Thermo-responsive rheological behavior of borinic acid polymer in dilute solution

Abstract

In comparison with other boron containing polymers, the investigations on the borinic acid containing polymers have been mostly ignored in spite of their easy synthesis. Our previous studies indicate a borinic acid polymer (PBA) holds promising potential as a new type of stimuli-responsive polymer. However, the property investigations were mainly based on turbidity changes. Here, we report the rheological property investigations of PBA solution. The PBA dilute solution (0.1 wt%) in DMSO exhibits a relatively high modulus (G′ of ∼60 Pa and G′′ of ∼15 Pa) at the frequency of 1 rad s⁻¹ at 25 °C. Temperature dependent rheology results reveal the thermo-responsive rheological behavior of the PBA dilute solution. Mechanism investigations indicate the coil–microgel transition of the PBA chains plays important roles in the thermo-responsive rheological behavior of the PBA dilute solution. This work therefore extends the field of thermo-responsive polymeric materials and opens up a new avenue in the applications of borinic acid containing polymers, where thermo-responsive rheology changes play an important role.