BRITE Relaunch: Multiscale Modeling of Adhesion, Friction, and Delamination Resistance on Non-Smooth Polymer Adhesive Surfaces

An increasing number of engineering innovations rely on functional surfaces that transmit mechanical forces, thermal fluxes, electromagnetic fields, sensing signals, and other physical information. Although soft polymers are excellent candidates for synthetic adhesives and coatings on functional surfaces, it is unclear why surface roughness, often due to manufacturing processes, damage, or design topography, sometimes compromises the polymer’s ability to fully bond with the surface, thereby disrupting its function. This BRITE Relaunch award supports fundamental research that seeks to elucidate the multiscale mechanisms of adhesion, friction, and delamination on non-smooth polymer surfaces. Insights from this research will promote technological advances in areas critical to the strategic interests of the United States in aeronautics, biotechnology, microelectronics, and smart materials. Synergistic partnerships with research and educational institutions across the US will cultivate STEM student training and professional development, increase participation in STEM education, research and innovation, and foster collaborations with local high schools and predominately undergraduate institutions to reach a broader population. Non-smooth surfaces have long been thought to improve adhesion with soft polymers by increasing surface energy and delaying delamination failure. Recent studies, however, have shown that surface roughness leads to adhesion hysteresis wherein parts of the surface come in and out of contact. Hysteresis reduces the effective contact area and can cause stress concentrations triggering local damage progression. This project seeks to characterize adhesion, friction, and delamination on non-smooth interfaces with soft polymers using multiscale computational models. The methodology looks to leverage atomistic-level simulations to inform a continuum-level interface formulation for bonding with soft polymers that will account for adhesion hysteresis, stress concentrations, and delamination patterns on surfaces with random topologies. Experimental tests on 3D-printed samples will be conducted to validate the numerical models. The methods intend to will facilitate understanding of interface mechanics and functional surface design for a wide range of engineering applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.