Aqueous ethanol-induced scissor effect promoting homogenization of PVA hydrogels for biomedical applications

Poly (vinyl alcohol) (PVA), a widely used soft material, is playing a pivotal role in daily products and biomedical materials due to its biocompatibility and favorable physical properties, yet PVA hydrogels grapple with high-energy dissolution and structural heterogeneity arising from dense interchain hydrogen-bonding networks. Furthermore, traditional fabrication strategy often yields non-uniform aggregates or requires cytotoxic solvents, limiting precise structural control. Here, we propose an eco-friendly strategy using ethanol/water mixed solvents to trigger a “molecular scissor effect”. Ethanol acts as a molecular scissor, intercalating into and weakening the robust PVA hydrogen-bonding network. This effect reduces the dissolution energy barrier, enabling rapid, homogeneous chain dispersion at significantly lower temperatures (70 °C ∼ 40 min) compared to pure-water systems (85–95 °C for 120 min). Consequently, this homogenization eliminates microscopic aggregates, fostering a more uniform molecular architecture. In addition, the zwitterionic monomer [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (SBMA) is incorporated, whereby the resulting multi-scale crosslinked network exhibits enhanced moisture retention and structural stability. The hydrogels demonstrate extraordinary mechanical toughness–sustaining loads exceeding 2000 times their own mass–alongside excellent reversible elasticity and a solvent-mediated “programmable mechanical response”. Moreover, biocompatibility assays confirm high cell viability. This strategy provides a molecular-level dissolution-regulation mechanism for strongly hydrogen-bonded PVA systems for overcoming processing bottlenecks in strong hydrogen-bonded polymer systems, offering significant potential for high-performance wearable sensors and tissue engineering scaffolds.