Mussel-inspired 3,4-dihydroxybenzaldehyde-modified polyvinyl alcohol fibers with superior mechanical properties

Polyvinyl alcohol (PVA) fibers demonstrate considerable potential for application in industries such as manufacturing, medicine, construction, and daily life due to their unique physical and chemical properties. However, their mechanical properties and thermal stability still require further improvement. Inspired by the molecular structure of mussel foot proteins and their reinforcement mechanisms, we synthesized PVA grafted with various amounts of 3,4-dihydroxybenzaldehyde (DBA) via an aldol condensation reaction under acidic conditions. We then prepared a series of 3,4-dihydroxybenzaldehyde modified polyvinyl alcohol (DPVA) fibers using wet spinning technology. The results showed that the introduction of catechol groups disrupted the hydrogen bonding and crystallinity among PVA molecules, leading to a decrease in the viscosity of the spinning solution, fiber crystallinity, and the maximum thermal decomposition rate. However, during the formation of DPVA fibers, π-π interactions and an enhanced hydrogen bond network improved the tensile strength of the fibers, increasing it from 2.8 cN/dtex to 6.64 cN/dtex. Additionally, the cross-sectional morphology of the fibers changed from a kidney shape to a flat kidney shape, further indicating an improvement in their structural characteristics. This study's results provide novel insights into how the mechanical properties of PVA-based fibers can be optimized.