A Physical Chemistry Lab Experiment Demonstrating Tunable Wettability

We recently designed a physical chemistry laboratory experiment that brings materials which were designed as part of our active research projects into the undergraduate laboratory curriculum.

Sarbajit Banerjee, Texas A&M University

A) Overview of the differences in wettability of ZnO-functionalized stainless-steel mesh surfaces generated by students in lab depending on differences in surface functionalization with either Octadecyltrichlorosilane (ODTS) or (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (HDF) and choice in the probe liquid (oil or water) that interacts with that surface.

We recently designed a physical chemistry laboratory experiment that brings materials which were designed as part of our active research projects into the undergraduate laboratory curriculum.

Students explore the thermodynamic principles of wettability by designing ZnO-tetrapod-based coatings. Coating a surface with layers of these nano- to micrometer sized tetrapods creates a highly textured surface which enhances the inherent wettability of the surface chemistry. By tuning the extent of texturation and the nature of surface functionalization, students prepare coatings which cause oil and water droplets to bead up and readily roll away, surfaces upon which oil and water flash spread and quickly wet the surface, and surfaces which demonstrate a range of interactions in between. As shown in the accompanying figure, this provides a strikingly visual means to demonstrate the effects of subtle changes in intermolecular interactions. 

Our prior work has demonstrated the use of these ZnO-tetrapod-based coatings in improving handling and transportation of viscous oils, which typically requires substantial heating and dilution with lighter hydrocarbons to enable flow and is thus an energy intensive extraction process. The article was featured as the cover of Journal of Chemical Education.1

Designing Materials to Revolutionize and Engineer our Future (DMREF)