Soft Matter Seminar: Sticking Like Barnacles: Mimicking a Novel Class of Underwater Adhesive Nanomaterials
Dr. Christopher R. So, US Naval Research Laboratory
Abstract: The common strategy to develop bioinspired underwater adhesives is the incorporation of specific chemistries into synthetic polymers or proteins. However, many organisms—including barnacles—use amyloid-like materials to produce successful adhesives, relying on the aggregation of proteins rather than extraordinary chemistry to achieve durable underwater bonding. Recently, we demonstrated that amyloid-based underwater adhesives can be formed from commercial proteins via heat, and now we further show that chemical denaturants can cure adhesives underwater at room temperature. The long history of protein processing in biochemistry and medicine provides diverse chemicals with which to produce protein-based glues. Here, we fabricate a two-part waterborne protein adhesive that rapidly sets at room temperature using off-the-shelf proteins and curing agents. We link protein denaturation and structure to the curing process using gel inversion tests, differential scanning calorimetry, rheometry, and infrared spectroscopy. These methods demonstrate the function of adhesive components, and formulations are optimized which set within minutes at room temperature. These adhesives produce bond strengths comparable to many synthetic bioinspired adhesives when tested by lap shear after exposure to dry and wet conditions. The ease with which these glues can be fabricated paves the way for opportunities with other commercial proteins and curing agents as a new avenue to produce scalable underwater adhesives.
Michael C. Wilson1, Qin Lu2, Kaitlin R. Nachtrieb3, Jackson S. Fuller3, Chloe M. Skogg3, Elizabeth A. Yates4, Matthew D. Thum5, Christopher R. So2
1NRC Postdoctoral Associate sited in Chemistry Division, Code 6176, Naval Research Laboratory, 4555 Overlook Ave SW, Washington DC, USA
2Chemistry Division, Code 6176, Naval Research Laboratory, 4555 Overlook Ave SW, Washington DC, USA
3U.S. Naval Academy MIDN sited in Chemistry Division, Code 6176, Naval Research Laboratory, 4555 Overlook Ave SW, Washington DC, USA
4U.S. Naval Academy Faculty sited in Chemistry Division, Code 6176, Naval Research Laboratory, 4555 Overlook Ave SW, Washington DC, USA
5Chemistry Division, Code 6124, Naval Research Laboratory, 4555 Overlook Ave SW, Washington DC, USA