Review on the Structure-Property Relationship of Lignocellulosic Materials Measured by Atomic Force Microscopy

In this review, we provide an overview of how atomic force microscopy (AFM) measurements on wood or other plant fibers help us understand the structure-property relationship in growing plants, matured wood material, and wood modifications and aging. We selected wood as a model material that can represent a number of lignocellulosic systems and attempted to address the structure-property relationship, as studied in situ. We selected AFM because it allows scientists to study materials in an unaltered, in situ form and relate chemical composition to material properties at a nanoscale level. We summarized the high-resolution measurements of wood cell walls such as topography, adhesion force, modulus, and chemical functional groups using AFM. Our three focus areas were: (1) how the cell wall develops its structure and property in living trees; (2) how the ultrastructure determines cell wall property; and (3) how the modification/aging of the cell wall changes its property in application scenarios.