Nanoindentation creep properties of the S2 cell wall lamina and compound corner middle lamella

We are working to better understand the mechanical properties of wood and the eects of adhesives and chemical treatments on those properties. Our approach is to introduce a variety of chemicals to selectively interact with components in wood—lignin, cellulose, and hemicellose—thereby helping us to isolate the roles played by each of the components. We probe mechanical properties at the sub-cellular level by investigating the S2 cell wall lamina (SCWL) and compound corner middle lamella (CCML) with nanoindentation. We have invented a unique set of nanoindentation methods that isolate the viscoplastic creep properties across 4 to 5 orders of magnitude of strain rate in µm-scale regions. Unlike most nanoindentation methods that purport to map out spatially varying viscoelastic or viscoplastic properties, our methods are quantitative, sensitive to a wide range of material response, and they remove artifacts brought about by heterogeneities within the structure. In this study we modify wood with ethylene glycol and monitor the change