(680i) Surface Topology and Modulus Effects on Adhesion in Novel Polyorganosilozane-Based Coatings

One of the ongoing effects of global climate change is the opening of previously inaccessible waterways in the Arctic. The availability of these areas to shipping and resource exploitation necessitates an increased coast guard and naval presence in these regions. Operating in conditions of extreme cold has leads to a number of issues, not the least of which is the build-up of ice on ship superstructures. As a result, the development of coatings that minimize ice adhesion is an on-going priority. We have studied the impact of coating properties on ice-adhesion for a series of novel polyorganosiloxane-based coatings. These coatings, based on the Hybridsil platform developed by Nanosonic, Inc (Pembroke, VA,) have exhibited exceptionally low ice adhesion and durability properties. The current work has focused on understanding the relationship between the surface morphology, chemistry, and modulus of the coatings on the ice adhesion behavior. Attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) was carried out to examine the chemical nature of the coating surface. In general, only small differences were observed in the IR spectra between samples. Atomic Force Microscopy (AFM) was used to image the coatings and to measure the modulus at different locations. Significant differences in film roughness and homogeneity are observed in the AFM imaging, both in the height images and the phase contrast images, depending on the specific formulation and method of coating application. These lead to significant differences in ice adhesion. In addition, force curves were obtained for a subset of samples and were analyzed to determine the film moduli. We observed differences in the film moduli both between different samples and at different locations for a single sample (i.e. between low and high points on the film.) These spatial variations also impact the strength of ice adhesion on the coatings. The coating chemistry is important in order to create a durable film with a low affinity for interactions with water ice; however, it is vitally important to understand and control the coating surface properties in order to achieve the desired low values for ice adhesion.