Fracture mechanics for preparation of ultrathin materials
Owing to their outstanding physical and mechanical properties,ultrathin materials(e.g.,graphene,molybdenum disulfide,and two-dimensional metallic nanomaterials)have long-term research interests in mechanics,condensed matter physics,materials science,and other fields.Exfoliation and transfer of ultrathin materials are important procedures in related experimental studies.This article reviews the progress in the preparation of ultrathin materials in the laboratory and studies fracture mechanics during the preparation process.The principles of interfacial fracture and exfoliation criteria are introduced for the classical mechanical exfoliation and polymer substrate buckling-enabled exfoliation(PSBEE)methods,respectively.Compared with the classical mechanical exfoliation method,PSBEE introduces smaller membrane stress in the materials,resulting in ultrathin materials with large in-plane sizes.Finally,future research directions are discussed concerning the interfacial fracture mechanics for ultrathin materials.