The conformability of wet pulp fibres has long been recognized as a key factor in the papermaking process. In order for fibres to bond in the sheet, their surfaces must be brought into contact.
The conformability of wet pulp fibre surfaces at extremely low forces (nN) and displacements (nm) was investigated by micro-indentation measurements with a standard AFM tip and cantilever. Force-distance curves were measured as the tip impacted wet sulphate softwood fibre surfaces. The surface stiffness showed a large variability, even at different locations on the same fibre surface. Rough estimates of the local apparent elastic modulus of the wet fibres gave low values in the 0.01 GPa range.