Intrinsic friction analysis—Novel nanoscopic access to molecular mobility in constrained organic systems

Condensed organic materials designed for nanotechnological applications are impacted significantly by internal and external constraints. Internal constraints are inherent to the molecular architecture, and generally result from direct bonding, electrostatic interactions, or steric effects. Internal constraints can be incorporated a priori into molecular designs, as a prescription for desired material properties. Today's challenge lies in obtaining information about the molecular mobility, in particular, in thin organic structured or unstructured films. A method that has been recently introduced, and is well suited for free surface analysis of complex organic thin film materials is intrinsic friction analysis (IFA), a spectroscopic analysis method based on scanning force microscopy (SFM). Here, we present a critical assessment of the method with practical illustrations towards the study of intramolecular and molecular mobilities in amorphous organic non-linear optical (NLO) materials, specifically self-assembling molecular organic glasses and complex organic polymer side-chain systems.