Green synthesis of bioinspired superhydrophilic copolymers from functionalized lactic acid and maltotetraose for sustainable applications

In nature, many plants and animals like aloe vera and snail rely on secreted mucus containing abundant hydrophilic polysaccharides, protein, and metal ions to maintain surface wettability and antibacterial properties. Inspired by this natural design, a biomimetic superhydrophilic polysaccharide based on lactic acid and maltotetraose, named PLM, was developed. Zinc acetate was introduced to construct a physical crosslinked network through the complexation between Zn 2+ and oxygen atoms, accompanied by an antibacterial effect on Escherichia coli and Staphylococcus aureus . PLM not only shows good spinnability, evidenced by a porous film with superior water absorption ability, but also can be used as a superhydrophilic coating on various substrates (e.g., polyethylene), with a minimal water contact angle of 5.68°. The strong affinity of PLM for water molecules that has been validated by Raman spectra and molecular dynamics simulations, along with nanoscale roughness, imparts great anti-fogging and anti-oil-fouling properties to coatings. Even after repeated heating-cooling cycles, tape adhesion, or mechanical friction, PLM coatings still present durable hydrophilicity, derived from the improved PLM intermolecular force and the adhesion of PLM to substrates by the dynamic crosslinked structure. The three-in-one multifunctional PLM reveals wide applicability and practicality in the fields of green coatings and films.