Fibrous surfaces exhibit unique mechanical properties based on fiber alignment. Vertically aligned fibers enhance friction and adhesion, while horizontal fibers act as lubricants reducing friction. Many plants form a fibrous mucilage cover around their seeds upon hydration, composed of cellulose, hemicelluloses, and hydrophilic pectins. Controlled critical-point drying of this hydrated seed mucilage from three plant species reveals free-standing cellulose nanofibers with high aspect ratios anchored to the seed surface. These nanofibers, similar in structure to vertically aligned carbon nanotubes and the adhesive contact elements in geckos, show exceptional dry friction and adhesion. Tribological experiments indicate high friction coefficients (1.4 to 1.8) when a smooth, stiff probe slides over the surface of these cellulose nanofibrils. This high friction is likely due to the bending of single cellulose fibers and their close alignment with the counterpart surface. Free-standing cellulose nanofibrils from seed mucilage are promising as a natural, eco-friendly material for applications requiring high contact forces in dry environments. – Journal cover design by scapiens
[Scientific Journal cover design] Low-Thermal-Budget Fluorite-Structure Ferroelectrics for Future Electronic Device Applications
In article number 2100028, Jiyoung Kim, Si Joon Kim, and their team review key factors involved in developing fluorite-structure ferroelectrics
