MSE Talks: Emily Asenath-Smith

Speaker: Emily Asenath-Smith

Title: Ice on Surfaces: A problem of adhesion by a crystalline material

Bio: Dr. Emily Asenath-Smith leads both the Ice Adhesion Facility and the Advanced Materials Team at the US Army Engineer Research and Development Center (ERDC) Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, NH. Through the Ice Adhesion Facility, Dr. Asenath-Smith supports a diverse customer base in testing and evaluation services with both routine and novel approaches to ice adhesion research. She also leads a research and development program in ice adhesion that is specifically addressing the testing and analysis aspects of ice adhesion to provide a basis for interpreting the performance of coating technologies so that they can be transitioned to field applications in civilian and military settings. With her Team, Dr. Asenath-Smith broadly leads research that addresses surface chemistry, interfaces and crystallization of materials in terrestrial cold conditions. Her team studies the materials science of ice, including the effect of impurities on the structure-property relationships of ice, ice adhesion, and ice crystallization.

Abstract: Widely the field of adhesion is concerned with soft adhesives; those based on poorly or non-crystalline polymeric materials. In a very different context, the attachment of ice to surfaces is also an adhesion scenario; however, it involves a crystalline material as the adhesive. Unlike most soft adhesives, which are engineered for high bond strengths, ice is a surface foulant that forms rampantly in natural environments and therefore cannot be engineered to have specific adhesive properties. As a result, the chemistry, structure, and properties of surfaces must be engineered to prevent ice from sticking or facilitate ice removal from surfaces with as little energy input as possible. The question then becomes, how to assess the effectiveness of a surface to resist ice adhesion? The study of ice adhesion is more complicated than just measuring the force required to remove ice from a surface of interest. There are many diverse scenarios under which ice forms and these various forms of ice adhere to and delaminate from surfaces differently. Ultimately, the key issue in the field of ice adhesion is that there are no formal standards for assessing the ice mitigation potential of engineered surfaces, and physics-based analysis approaches are lacking. As a result, there are almost as many ice adhesion tests across the field as there are researchers developing surface coating technologies to mitigate icing. The focus of this talk is on research about testing methods and analysis approaches for ice adhesion. The growth/adherence of ice on/to surfaces will be discussed, including methods to achieve control over ice microstructures at variable temperatures using a crystallization from the melt apparatus. Ice adhesion testing configurations will be addressed, including shear and tensile delamination modes. Experimental results on ice adhesion testing and surface characterization will be presented along with a structural-mechanical computational model to provide insights into generalizable analysis methods that will aid decision making around ice mitigation technologies.

Student Host: Wenlu Wang