(296g) Controlling Surface Morphology and Mechanical Properties Through Marangoni Effects and Surface Energies in Creating Multifunctional Epoxy- Clay Nanocomposites

Shenk, T., South Dakota School of Mines and Technology
Winter, R. M., South Dakota School of Mines and Technology
Benjamin, K. M., South Dakota School of Mines and Technology

Polymer nanocomposites (PNC) provide unique solutions to industrial and scientific applications.  Researchers are interested in improving the ability to tailor a product to meet specific weight, thermal, optical, mechanical and electrical requirements.  The ability to control surface morphology and nanoparticle dispersion is critical in creating multifunctional multilayer epoxy-clay nanocomposites.

Surface morphology and adhesion are greatly impacted by the interfacial interactions between substrate and reacting substance, as well as concentration and temperature gradients within the system.  Within epoxy systems, controlling the humidity plays a key role as well, as it provides a mechanism for competing reactions.  Controlling environmental aspects such as temperature, humidity, and the concentration gradients all play key roles in creating the desired properties in PNC’s.

This project explores the importance of surface energy dynamics, concentration and temperature gradients encountered in spin coating in controlling Marangoni effects impact on surface morphology and the impact of nanoparticles and their dispersion within these systems on mechanical properties of single and multilayer composites. It explores the importance of substrate-epoxy and epoxy-air surface interactions.  We show in this study that in controlling the environment pre- and post spin coating, multilayer thin film nanocomposites can be created targeting different material properties such as strength, adhesion, morphology, thickness, density and coefficient of thermal expansion (CTE). Fluids are characterized through tensiometric and rheological measurements.  Film properties are characterized through optical, AFM, SEM, TEM, and DMA measurements.  Computational simulations of surface energy and surface tensions will also be conducted to confirm experimental results and provide a possible explanation of the dynamics of interfacial phenomena occurring at the molecular level.