In-situ nanomechanical testing at elevated humidities

Nanoindentation is an ideal technique to study local mechanical properties of a wide range of materials on the sub-micron scale. It is a well-established tool to investigate biological materials in the dry state. However, their properties are strongly affected by their moisture content, which until now has not been consistently controlled. Recently, we developed an experimental set-up for measuring local mechanical properties of materials by nanoindentation-based methods in a controlled environment of relative humidity (RH) and temperature. This system is currently widely used in the domains of inorganic and biological materials. Nevertheless, studies that require to employ in-situ nanomechanical characterization are still limited to materials that are not affected by relative humidity. Mainly, because these experiments are conducted inside an electron microscope, i.e. in high vacuum. In this work, we develop an experimental platform to perform in-situ nanoindentation-based experiments in relative humidities of up to 100%. A number of applications of this experimental set-up will be presented