Facile preparation of transparent poly (γ‐glutamic acid) modified poly (vinyl alcohol) hydrogels with high tensile strength and toughness

Abstract In the present work, a transparent poly (γ‐glutamic acid) modified polyvinyl alcohol (γ‐PGA/PVA) hydrogel with excellent tensile strength and toughness was prepared by a simple and effective immersion method. Results revealed that γ‐PGA concentration and immersion time have great influence on the mechanical properties of prepared γ‐PGA/PVA hydrogels. The mechanical tensile strength of γ‐PGA/PVA hydrogel reached to 16.68 ± 0.43 MPa with the strain of 511.64% ± 23.38% when prepared PVA hydrogel was immersed in 20% γ‐PGA solution for 24 h (denoted as 20% γ‐PGA/PVA). Meanwhile, 20% γ‐PGA/PVA hydrogel exhibited excellent mechanical properties, such as high‐level torsion, knotting and puncture resistant, and can lift a 5 kg weight without obvious rupture. The morphology, structure, compositions and mechanism of enhanced mechanical properties were investigated. Besides the excellent mechanical properties, 20% γ‐PGA/PVA hydrogel possessed good conductivity as well as high sensitivity to external strain. Furthermore, in vitro good cytocompatibility of 20% γ‐PGA/PVA hydrogels was demonstrated by using MC3T3‐E1 cells. Therefore, the prepared 20% γ‐PGA/PVA hydrogel may provide the possibility for the applications in the field of cartilage repair/regeneration, artificial skin and human motion sensor.