Designing Cooperative Hydrogen Bonding in Polyethers with Carboxylic Acid Pendants

Abstract

As a primary molecular interaction governing unique phenomena found in nature, hydrogen bonding (H-bonding) has played a significant role in the design of functional polymeric materials. We herein present the design and synthesis of poly(glycidoxy acetic acid) (PGA), which involved H-bonding donor and acceptor moieties within a single repeating unit of polyether for the precise control of the cooperative H-bonding in polymer chains. The monomer-activated ring-opening polymerization of a functional epoxide monomer, t-butyl glycidoxy acetate, followed by hydrolysis, produced the desired PGA polymers in a controlled manner. The high-level synergistic interplay between the intermolecular and intramolecular H-bonding in the PGA chains was demonstrated with pH-dependent self-association properties in the solution state and stronger adhesion properties in the bulk state compared with the conventional H-bonding mixture of poly(ethylene oxide) and poly(acrylic acid). Furthermore, the molecular dynamics simulations reveal the relative contributions of the respective H-bonding interactions within the polymers in both the solution and the bulk states, thereby highlighting their crucial role in the properties of PGA. Finally, we anticipate the potential applicability of PGA in biological and biomedical fields due to its excellent biocompatibility.