XPS and the medium-dependent surface adaptation of cellulose in wood

We report reproducible XPS experiments on wood in two case studies. In the study on natural wood aging, we compared XPS bulk wood compositions of ancient and modern materials, analyzing spruce wood used as structural elements in roofs. Freshly cut specimens were analyzed before and after acetone extraction. In the other study, on wood surface aging, we used recently harvested, frozen pine as the sample material. In this experiment, never-dried wood surfaces were exposed to dry conditions via different routes. Combining the data presented here with our earlier studies on paper and a recent solvent-exchange study on nanofibrillated celluloses, we propose that both the lack of aging in the bulk wood and the rapid aging of the exposed wood surfaces are driven by the same process, i.e. the medium-dependent surface adaptation of nature-derived celluloses. Controlling this adaptation process is of a crucial importance in many technological applications of cellulose and wood materials.