A new surface forces apparatus for nanorheology

We present an original surface forces apparatus which enables us to measure the interaction forces between any solid surfaces such as, e.g., metallic surfaces, opaque surfaces, or rough surfaces. The relative displacement of the surfaces is measured with a capacitive sensor. The forces are measured by a stiff and highly sensitive interferometric sensor. The measurements are performed in a dc to 100 Hz bandwidth. This feature allows us to study the mechanical response of a nanometric confined medium to rapid strain variations in the linear regime. An example of nanorheological measurement of dodecane confined in a nanometric gap is given at the end of this article.