Student-written Problems that Reverse Engineer YouTube Videos and Crosslinked Polymeric Anion Exchange Membranes

This dissertation contains findings from two research projects. The first research area focused on assessing engineering students problem solving skills. Problem solving related to two material and energy balance topics – vapor liquid equilibrium and reacting systems with recycle - were examined first followed by a more holistic analysis across two cohorts. Research employed a pseudo-control/treatment design across two cohorts to examine impacts of replacing Textbook problems with student-written, video-inspired (YouTube) problems. The Treatment group completed both YouTube and Textbook problems, while the Control group completed only Textbook problems. Problem solving skills was assessed with an established rubric modified by the research team. Also, the NASA Task Load Index survey quantified the difficulty of homework problems. For each cohort, findings were drawn from 9 YouTube problems and 10 textbook problems, ~2000 task-load surveys and ~2500 problem solving scores compiled by multiple raters. Each of Treatment and Control groups were compared across cohorts to verify outcomes. In general, students displayed higher problem solving on YouTube problems compared to Textbook problems. Students perceived YouTube problems to be of statistically similar difficulty as Textbook problems. The Treatment group showed improvements in problem solving (effect size: Hedges g = 0.1 to 0.6), which was verified across two cohorts.The second research area developed a recently patented anion exchange membrane intended for use in electrochemical devices. The chemistry, processing, and characterization of anion exchange membranes, created by crosslinking a commercially available polyelectrolyte, poly (acrylamide-co-diallyldimethylammonium chloride), with glutaraldehyde, were studied. Crosslinking was confirmed through Fourier-transform infrared spectroscopy by the presence of a new C=N bonds. The influence of four parameters to optimize AEM properties: crosslinker/polyelectrolyte mole ratios, polyelectrolyte concentrations, drying temperature, and drying time of AEMs were examined. In addition to physical and chemical characterization, mechanical properties under both wet and dry conditions, including strength at break, Young’s modulus, and elongation, were measured using an extensional rheometer tool and custom-built humidity oven. AEMs were ~30 microns thickness, which is important for lowering the resistance for ion transport and should result in higher ionic conductivity. As hypothesized, increases crosslinker to polyelectrolyte ratio decreased water uptake, IEC, and conductivity. In addition, improved alkaline stability and mechanical strength at wet conditions were found in membranes with larger crosslinker to polyelectrolyte ratios. Next, increased polyelectrolyte concentration did not show a strong relationship with strength at break of AEMs, disproving the hypothesis that higher polyelectrolyte concentrations having many entanglements would improve mechanical properties. Overall, AEMs with encouraging properties were created, including water uptake