The gradient stripe was quickly placed under a stationary knife edge of equal length. The gradient stripe was spread as a film, orthogonal to the composition gradient direction, for a distance of 40 mm with the flow coating procedure described above. After a few seconds most of the solvent evaporated, leaving behind a thin film with a gradient of polymer composition. Cloud points measured with conventional light scattering are shown as discrete data points and agree well with the phase boundary observed on the library. The diffuse nature of the phase boundary reflects the natural dependence of the microstructure evolution rate on temperature and composition.
Bright regions are more dewet than dark regions.
Figure 2 presents a composite optical image of a typical T-h library that indicates different dewetted structures and growth rates as a function of T and h. The libraries are able to reproduce a wide range of dewetted structures observed with our own uniform control samples and in previous work of others for similar systems, validating our methodology. The method presented here is unique in its ability to rapidly identify fundamental trends in film stability, nucleation mechanisms, and dewetting kinetics over a wide range of parameter space. Figure 1 . Photograph of a combinatorial library showing LCST phase boundary for PS-PVME with validating data from conventional scattering cloud points.