Fabrication of Anisotropic Poly(vinyl alcohol) Scaffolds with Controllable Mechanical Properties and Structural Recoverability under Compression via a Freeze-Casting Technique

In this study, poly(vinyl alcohol) (PVA) scaffolds are fabricated by an advanced polymer-based freeze-casting method. The sintering process for ceramic-based scaffolds is replaced by cross-linking. It is essential that the selected polymer is water-soluble and cross-linkable. The cross-linking temperature for PVA is 180 °C and it does not require sintering at high temperature as in the typical freeze-casting method. The ultimate compressive strength of PVA scaffolds is measured to be 11 MPa at 75% RH. In the axial direction, the stress–strain curve shows ductility and exhibits a series of jagged breaks after the yield strength. In the radial direction, the scaffold shows compressibility that nature recovery percentage at least exceeded 90% below the strain of 50% and shows complete recoverability via the swelling/deswelling process below the strain of 60%. In summary, the PVA scaffold possesses anisotropic mechanical strength, structural recoverability, and humidity regulating properties, which can be applied as multifunctional materials.