Heonjoo Ha

The glass transition temperature (T ), in-plane diffusivity (D), and effective viscosity (? ) were measured for the same thin film system of poly(isobutyl methacrylate) supported by silica (PiBMA/SiOx). We found that both the T and D were independent of the film thickness (h ), but ? decreased with decreasing h . We envisage the different h dependencies to be caused by T , D, and ? being different functions of the local T ’s (T ) or viscosities (? ), which vary with the film depth.

The Marangoni effect describes fluid flow near an interface in response to a surface tension gradient. Here, we demonstrate that the Marangoni effect is the underlying mechanism for flow driven feature formation in an azobenzene-containing polymer film; features formed in azobenzene-containing polymers are often referred to as surface relief gratings or SRGs. An amorphous poly(4-(acryloyloxyhexyloxy)-4′-pentylazobenzene) was synthesized and studied as a model polymer.