Synthesis of a trident-like functional monomer and its utilization in the functionalization of polymer side chains with salt-responsive properties

The performance of water-soluble polymers is dependent on the structural characteristics of their side chains. In this study, we synthesized a trident-like functional monomer, AC-1810-TFM, with a hydrophobic tail and double ethoxy groups tails through two quaternization reactions. Subsequently, the monomer was copolymerized with acrylamide and acrylic acid to prepare a functional polymer (PAAAC) containing hydrophobic and ethoxy groups in its side chain. PAAAC exhibited positive response to NaCl, negative response to Ca2+, and controllable response to mixed ions in saline water due to chelation between ethoxy groups and Ca2+ as well as hydrophobic interactions confirmed by SEM images. Owing to its salt responsiveness, PAAAC has great potential for improving injectivity, mobility control, proppant suspension, and foam stability. Our strategies for fabricating functional monomers and polymers may serve as references for designing new materials with excellent salt responsiveness.