Determination of the shear modulus in self-assembled monolayers using quartz resonators

摘要

This work examined self-assembled monolayers (SAMs) of n-alkane thiols using quartz resonators to determine the shear storage and loss moduli. Network analyzer measurements of electrical admittance at fundamental and corresponding harmonic values are fit to an equivalent circuit model. Shear modulus depends on frequency; the modulus values are three orders of magnitude lower than expected for a liquid or elastomeric polymer, more like those of a dense gas or supercritical fluid. A density of around 0.45 g/cm(sup 3) is calculated for a dodecane thiol SAM; this is roughly half of the bulk density. In conclusion, quartz resonators can be used to inertially deform SAMs.