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Investigating the Process of Surface Degradation and Nanoparticle Release of a Commercial Nanosilica / Polyurethane Coating Under UV Exposure



Deborah S. Jacobs, Yu L. Cheng, Savelas A. Rabb, Peter J. Krommenhoek, Lee L. Yu, Tinh Nguyen, Li Piin Sung


Considerable research has shown that many coatings properties such as mechanical, electrical, and ultra violet (UV) resistance are greatly enhanced by the addition of nanoparticles, which can potentially increase the use of nanocoatings for many outdoor applications. However, because polymers used in coatings are susceptible to degradation by weathering, nanoparticles in a coating may be released into the environment during the life cycle of a nanocoating. Therefore, the goal of this study is to investigate the process and mechanism of surface degradation and particle release from a commercial nanosilica/polyurethane coating under accelerated UV exposure. Recent research at the National Institute of Standards and Technology (NIST) has shown that the matrix in a polymer nanocomposite undergoes photodegradation during exposure to UV radiation, resulting in accumulation of nanoparticles on the composite surface and release from the composite. In this study, specimens of a commercial polyurethane coating containing silica nanoparticles were exposed to a well-controlled, accelerated UV environment. The nanocoating surface morphological changes and surface accumulation of nanoparticles as a function of UV exposure were measured, along with chemical change, mass loss, and possible particle release. To identify and characterize the nanosilica on the nanocoating surface at different exposure times, a non-destructive method, Atomic Force Microscopy (AFM), in Peak-Force tapping mode was used. Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (SEM-EDXS) was also used to verify the composition of particles as silica-based. Furthermore, released particles from the surface of the coating were collected using a simulated rain process developed at NIST. These specimens were measured using Inductively-Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to evaluate the amount of silica released from the nanocoatings. The results demonstrated that ...
Proceedings Title
Proceeding of American Coatings CONFERENCE
Conference Dates
February 10, 2015
Conference Location
Louisville, KY
Conference Title


Atomic Force Microscopy, Nanocomposite, Particle Release, Peak Force QNM AFM, SEM, UV Degradation


Jacobs, D. , Cheng, Y. , Rabb, S. , Krommenhoek, P. , Yu, L. , Nguyen, T. and Sung, L. (2015), Investigating the Process of Surface Degradation and Nanoparticle Release of a Commercial Nanosilica / Polyurethane Coating Under UV Exposure, Proceeding of American Coatings CONFERENCE , Louisville, KY (Accessed April 17, 2024)
Created March 11, 2015, Updated February 19, 2017