Abstract
The surface properties of micro-folded, “physically matted” acrylate coatings prepared via vacuum UV (VUV) treatment are described. By comparing micro-structured and smooth surfaces, static and dynamic friction values were determined. The topography of micro-wrinkled areas was scanned by an optical profiler and correlated to the gloss. In addition, the reproducibility of surface structure formation and their spatial frequency spectrum roughness have been analyzed using the power structural density functions calculated from the measured surface topographies. Since the high energy 172 nm photons (7.2 eV) are able to generate radicals in acrylates even in the absence of any photoinitiator, a highly crosslinked acrylate matrix was formed in the near surface range. As a result of the increased cross-link density, the micromechanical properties such as the surface hardness were improved. Selected data are presented.
Introduction
Materials
Surface topography
Micro-folded acrylate-based coatings were prepared from both an SL8 and an SD-L4 varnish. Both coatings were applied by roll coating on a lab-coater. Table 1 summarizes the most important parameters of these coatings.
Micro-profiling was carried out for two independent SL8 (only one shown in Fig. 3a) and two independent SD-L4 (only one shown in Fig. 3b) coatings. These measurements revealed the reproducibility of the micro-folding process as also demonstrated in Fig. 4. For quantification of the…
Conclusions
By analyzing the surface with optical profilometry we could demonstrate that the PSD profiles, calculated from the measured surface height profiles, provide excellent information on coarseness, homogeneity and reproducibility of the micro-structured surface texture. Referring to the matting effect it could be shown that there is a correlation between gloss and the aspect ratio. Furthermore, the gloss can be reproducibly manipulated by the process parameters. Unlike in conventional chemical…
Acknowledgments
The authors thank the Technologieförderung of the Sächsische Aufbaubank, Dresden, for funding the project and also all named companies for providing materials.
Autors among others are Dr. Rolf Schubert and Prof. Dr. Rainer Mehnert – VUV-induced micro-folding of acrylate-based coatings: 2. Characterization of surface properties – ScienceDirect