Nacre exhibits remarkable mechanical properties resulting from its hierarchical brick-and-mortar structures. By using pure shear stresses of torsion, we demonstrate how nacre resists the initial tablet sliding by tuning its nanoscale toughening mechanisms in dry and hydrated conditions. In hydrated nacre, hydrogen bonds between water molecules and organic matrices provide temporal paths for stress redistributions, through which the shear resistance is gradually transferred from mineral bridges to contacted nanoasperities. In the subsequent sliding, dynamical interactions between nacreous tablets enable substantial plasticity before the catastrophic failure of hydrated nacre. Our findings should help pursuing further insights into the interfacial behavior of natural and artificial laminated nanomaterials under different conditions.

珍珠母由于其分层的砖瓦结构而具有非凡的机械性能。通过使用扭转的纯剪切应力，我们证明了珍珠母如何通过在干燥和水合条件下调节其纳米级增韧机制来抵抗最初的片剂滑动。在水合珍珠母中，水分子和有机基质之间的氢键为应力重新分布提供了时间路径，通过该路径，剪切阻力逐渐从矿物桥转移至接触的纳米空隙。在随后的滑动中，珍珠质片剂之间的动力相互作用使得在水合珍珠质发生灾难性破坏之前，具有相当大的可塑性。我们的发现应有助于进一步了解天然和人工层压纳米材料在不同条件下的界面行为。