Freeze-Dried PVA Hydrogels with Superior Mechanical Properties: A Rapid Alternative to Conventional Methods

This study introduces a freeze-drying approach for physically cross-linked poly(vinyl alcohol) (PVA) hydrogels, significantly reducing preparation time while enhancing mechanical properties. Compared to conventional freeze-thaw (FT) and cast-dried (CD) methods requiring 4-10 days, our freeze-dried (FD) gels are prepared within 24 h. Spectroscopic analysis revealed that FD gels possess higher crystallinity than both CD and FT gels, with favorable spatial distribution of crystalline domains. This unique microstructure confers exceptional mechanical balance, combining high tensile strength comparable to CD gels with superior tear resistance similar to FT gels─properties typically difficult to achieve simultaneously. Despite accelerated processing, FD gels maintain equivalent swelling ratios to conventional methods. The rapid preparation coupled with enhanced mechanical performance positions these FD gels as promising candidates for industrial and biomedical applications, particularly for artificial cartilage and soft tissue engineering where both production efficiency and mechanical reliability are critical considerations.