Researcher(s)
- Caroline Moore, Material Science, University of Delaware
Faculty Mentor(s)
- Christopher Kloxin, Material Science and Engineering/ Chemical Engineering, University of Delaware
Abstract
Adhesive strength was evaluated on wet and dry substrates (glass and marble surfaces) using polymer networks with varying ratios of 2-hydroxyethyl acrylamide (HEAA) and bisphenol A-glycidyl methacrylate (BisGMA). 1:1, 5:1, and 10:1 molar ratios were used to regulate the crosslinking density, hydrophilicity, and mechanical properties of the adhesive network. All the polymer films were photo-initiated cured with 2 wt% photoinitiator under UV light to ensure uniform curing conditions for all compositions. The goal was to investigate how polymer structure and surface water affect pull-off adhesion, particularly in cases where water absorption or plasticization of the surface can affect bonding. Pull-off adhesion tests were conducted to determine adhesion strength on each substrate in dry and wet conditions. Initial results indicate a clear dependence upon substrate humidity and polymer content. For low crosslink density formulations on wet marble, greater adhesion was observed, which could be a consequence of increased hydrophilicity and network flexibility, possibly allowing better contact with the substrate. On dry surfaces, higher crosslink densities provided better mechanical stability but had lower adhesion in wet environments. Variations in glass and marble adhesion performance also show that surface porosity and water absorption are major considerations when looking at adhesion performance. These results throw some light on how polymer chemistry, specifically rigidity/hydrophilicity balance, controls adhesion under various environments.