Stratification of individual components in thermosetting coatings plays an important role during film formation and affects a number of macroscopic properties. This behavior is particularly pronounced for water-borne coatings, and therefore molecular level understanding of interactions in latexes and responsiveness of individual components during coalescence of water-borne polyurethanes are of particular interest. The presence of macromolecular arrangements and interactions among various components near the film-air (F-A) and the film-substrate (F-S) interfaces can be effectively monitored using attenuated total reflectance (ATR) and step-scan photoacoustic (SSPA) Fourier transform infrared (FT-IR) spectroscopy. Both approaches are capable of obtaining information from various surface depths and complement each other if one seeks molecular level information from 0 to 150μm into the film. In this presentation combined ATR and PA information along with IR and/or Raman surface imaging will be presented to establish three-dimensional representation of polyurethane film formation and the effect of copolymer/polymer blend latexes on coalescence processes in Sty/n-BA.