MSE Seminar Series: Kathryn Wahl
Friday, April 13, 2012
1:00 p.m.-2:00 p.m.
Room 2110 Chemical and Nuclear Engineering Bldg.
301 405 5240
A Sticky Situation: In Situ Chemistry and Mechanics of Barnacle Adhesive Formation and Curing
Naval Research Lab
Proteinaceous secretions are widely recognized to be significant contributors to marine biofouling. The resulting interfacial films can be physisorbed or chemisorbed, and have varying degrees of permanency they may be highly polymerized and cross-linked, or simply sticky enough to allow surface exploration. Conventional approaches to examining bioadhesive junctions are forensic in nature biofouler removal (separating the surfaces) followed by ex situ examination of the adhesive composition and surface morphology.
We have tackled a common marine fouler, the barnacle, with in situ approaches and tools that allow us to probe the bioadhesive interface as it develops. From these studies, we have learned that barnacles secrete and cure their adhesive through a multistage process. In this talk, I will present examples of how we have applied a broad suite of in situ microscopy and spectroscopy approaches to reveal how barnacles form and cure their adhesive, as well as its properties and composition. Our in situ approaches include performing temporally- and spatially-resolved microscopy and spectroscopy through adhesive interfaces transparent at UV, visible, IR, and x-ray wavelengths. We have used these and other materials science tools to extend our understanding of the properties and development of the adhesive interface of barnacles. Barnacle adhesion is promoted by both chemistry and structure at multiple scales. Further, the proteinaceous adhesive interface is formed in two steps, with the second process modifying the interfacial chemistry and increasing adhesion twofold. Ultimately, we aim to use this information to develop better antifouling strategies that reduce bioadhesive strength.