High-strength poly(vinyl alcohol) physical eutectogels: Effects of polymer molecular weight, DES composition, and heat treatment

A one-step manufacturing process is employed to fabricate stretchable physical eutectogels. It involves directly mixing polyvinyl alcohol (PVA) with choline chloride as a hydrogen bond acceptor and either ethylene glycol or glycerol (Gly) as a hydrogen bond donor. This process results in the formation of numerous crystallite domains of PVA within the deep eutectic solvent (DES), which act as physical crosslinking points in the eutectogel. The study systematically investigates the effects of PVA molecular weight, DES composition, and various heat treatments on the mechanical properties of eutectogels. The stress–strain curves demonstrate that a higher PVA molecular weight, the addition of Gly to the DES, and repeated freeze–thaw cycles can enhance the mechanical properties of the PVA physical eutectogel. Finally, scanning electron microscopy and X-ray diffraction are used to examine and analyze the polymer networks and crystallite domains in terms of pore size, crystallinity, and crystallite domain size.