PI: Christopher Bettinger
University: Carnegie Mellon University
High-performance adhesives that are effective in fluids have utility as materials for medicine, consumer projects, and industrial applications. To date, the design and implementation of materials that provide robust adhesion in aqueous or oily environments has been elusive. Various elaborations of bioinspired approaches have been implemented to overcome this formidable technical barrier. One such approach is to functionalize materials with catechol groups, chemical motifs in proteins that are used by organisms to adhere to inorganic surfaces in marine environments, for example. Catechols in these specialized natural proteins increase the interfacial adhesion to many substrate materials by forming coordination bonds, hydrogen bonds, and aromatic interactions.
To date, the design of synthetic catechol-bearing adhesives has been moderately successful, but many technology gaps remain.
There are three key problems with existing catechol-bearing adhesives:
- the areal density of adhesive catechols is low (less than 10 nmol/cm^2)
- the adhesive polymers delaminate from substrates (when used as a thin film) or undergo cohesive failure (when used as a bulk material)
- interfacial chemical bonding is reduced in rough surfaces.
We have recently discovered a novel technique to synthesize and transfer print catechol-bearing nanomembrane adhesives to virtually any polymer substrate. These adhesives, termed polydopamine nanomembranes, contain catechols at areal densities of about 26 nmol/cm^2. Furthermore, polydopamine nanomembranes can be covalently bonded to many industrial polymers, therefore reducing the risk of delamination of the functional adhesive film from bulk substrates.
In this project, we propose a partnership with nanoGriptech, a Pittsburgh-based company founded by a CMU professor that fabricates microstructured adhesive polymers for use in consumer products and industrial applications. Microstructured adhesives will be combined with polydopamine nanomembranes to address challenges with surface roughness. Specifically, we will integrate polydopamine nanomembranes with microstructured substrates to create a new class of high-performance adhesive that is effective in both aqueous and oily environments.