Dynamics of Nanoconfined Fluids measured by combined Force Microscopy and Fluorescence Correlation Spectroscopy

We present work performed on a model liquid, tetrakis(2-ethylhexoxy)silane (TEHOS), using Atomic Force microscopy (AFM) and Fluorescence Correlation Spectroscopy (FCS) to study its dynamical structure at the nanoscale. A novel homebuilt interferometer-based small amplitude AFM was used to measure directly the stiffness and damping coefficient of TEHOS film. Oscillations in stiffness and damping coefficient with period $\sim $1 nm (TEHOS molecular size) were observed. Translational diffusion in spin-coated TEHOS films was measured using Fluorescence Correlation Spectroscopy (FCS). Diffusion was found to be heterogeneous. Finally we present the ongoing work on an integrated platform of AFM and FCS to perform simultaneous measurements of nanoconfined fluids. Recent results using this new setup on a fluorescently labelled nanoparticle solution in confinement will be discussed.