Abstract
This study attempts to address the interpretation of atomic force microscopy (AFM) adhesion force measurements conducted on the heterogeneous rough surface of wood and natural fibre materials. The influences of wood surface roughness, tip geometry and wear on the adhesion force distribution are examined by cyclic measurements conducted on wood surface under dry inert conditions. It was found that both the variation of tip and surface roughness of wood can widen the distribution of adhesion forces, which are essential for data interpretation. When a common Si AFM tip with nanometre size is used, the influence of tip wear can be significant. Therefore, control experiments should take the sequence of measurements into consideration, e.g. repeated experiments with used tip. In comparison, colloidal tips provide highly reproducible results. Similar average values but different distributions are shown for the adhesion measured on two major components of wood surface (cell wall and lumen). Evidence supports the hypothesis that the difference of the adhesion force distribution on these two locations was mainly induced by their surface roughness.
Highlights
Atomic force microscopy (AFM) has been a useful method in adhesion force measurements, owing to its ability to identify surface forces at precise locations, and its suitability for various materials and environmental conditions
This study attempts to address the interpretation of atomic force microscopy (AFM) adhesion force measurements conducted on the heterogeneous rough surface of wood and natural fibre materials
Similar average values but different distributions are shown for the adhesion measured on two major components of wood surface
Summary
Atomic force microscopy (AFM) has been a useful method in adhesion force measurements, owing to its ability to identify surface forces at precise locations, and its suitability for various materials and environmental conditions. The results could provide valuable information for the use of AFM adhesion force measurements on wood and other heterogeneous rough materials. As a normal AFM tip has a radius of curvature which is comparable to the diameter of the macrofibrils, consideration of the wood surface roughness must be taken into account for the force measurement in this case. Wood fibre consists of cellulose, hemicellulose, lignin and small amounts of other extractives, which differ in content at different locations [11] On such a natural fibre surface, many factors influence the adhesion measured with AFM, including chemical composition, surface morphology, and water absorption and cut surface oxidation/deactivation (fresh versus old surface). We analysed repeated measurements with commercially available tips, and demonstrated the influence of tip wear on the reliability of adhesion measurement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
