Novel methods were developed to generate and characterize surface structures formed from polymer segregation within a powder coating system. A blend of unique acrylic polyol resins and low concentrations of matting agent afforded a durable coating exhibiting consistent low reflectance. An enhanced synergistic effect was observed from the phase separation and domain formation of the two polymeric resins with varying pendent hydroxyl group functionality and the incorporated matting agents. Together the domains and incorporated matting agents produced a significantly lower reflectance coating than the matting agent in combination with either polymeric resin alone. The rigorous thermal, optical, and spectroscopic analysis of the pigmented coating and control coatings culminated in the complete characterization of polymeric phases within the resulting coatings. Raman analysis of the control coatings via a distinct spectroscopic handle allowed for positive identification of the segregated polymer resins within the coating structure. Domains observed by optical microscopy within the control coating structure were chemically identified via Raman analysis as the high-hydroxyl content resin. Subsequent Raman mapping of the peak intensity over an entire cross-section provided consistent evidence for positive identification of the polymeric composition within the domain.
Keywords: Raman spectroscopy; domains; low gloss; polymeric phase separation; surface roughness.