Tunable thermosensitivity in multistimuli-responsive terpolymers

We designed new terpolymers responsive to pH, temperature, and metal ions. Binding of metal ions amplifies the magnitude of thermal response. Variations in the pH and concentration of metal ions enable tuning the lower critical solution temperature (LCST) and thermosensitivity in a broad range. Upon changes in pH and/or temperature, polymers form associates with narrow size distribution ranging from less than 5 nm to more than 250 nm in diameter. The multistimuli-responsive properties of newly synthesized polymers are the result of combining hydrophobic, ionogenic, and non-charged hydrophilic moieties within the terpolymer structure. Polymers are produced by a potentially scalable method from inexpensive starting materials, 2-hydroxyethylacrylate (HEA), butylmethacrylate (BMA), and acrylic acid (AA). Polymers and their aggregates are characterized by NMR, dynamic light scattering, and electron microscopy. The ability to control the size of polymer aggregates and the magnitude of response to external stimuli opens exciting opportunities for practical applications.