Quantifying Nanoparticle Self-Assembly : A QCM-D Study

There has been an increasing demand for analytical tools that can quantify the interaction and/or reaction of nano-scale particles, polymers as well as bio-molecules, with various surfaces. In-situ monitoring of changes of nano-scale materials, is of critical importance. If scientists and engineers have a more complete understanding of the behavior of materials at the nano-scale, new materials can be built from the nano-scale up.

Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D), a nanomechanical acoustic-based analytical technique, provides in situ, real-time characterization of the interactions of various polymeric and bio-materials at variety of interfaces. With QCM-D, simultaneous measurement of resonance frequency change (ÄF) and energy dissipation change(ÄD) is performed by periodically switching off the driving power of oscillation of the sensor crystal and recording the decay of damped oscillation as the adsorption and/or structural changes takes place at sensor crystal surface (Figure 1). While change in frequency provides information about mass changes, changes in dissipation (D) provides structural information about the viscoelastic properties of adsorbed films in real time.

This presentation will first review work that has previously been done utilizing QCM-D to quantify self-assembly processes. Then we will discuss recent results that have shown that we can follow (in real-time) the grafting of chemically-modified nanoparticles onto surfaces.