Modifying Gelators for Sensing Applications and Developing Online Resources for Organic Courses.

Abstract

Part 1 of this thesis focuses on utilizing low molecular weight gels in sensing applications. Because low molecular weight gels are stimuli-responsive, they are ideal candidates for sensing. One challenge in the field is designing a gelator for a specific application, since gelators are often discovered serendipitously. In chapter 2, we review recent work understanding how structure and solvent affect gelation, which has helped streamline gelator discovery. In chapter 3, we describe an example of how one can design a gelator for sensing, specifically to detect nitrite. By modifying a known azosulfonate gelator scaffold, we synthesized five new gelators and selected the best candidate to successfully detect nitrite in dirty water. A limitation sometimes observed in gel-based sensors is poor sensitivity, especially when the analyte is not catalytic. In chapter 4, we describe our efforts to amplify the analyte signal in gel-based sensors using disassembling polymers. We describe modifying monomers of two polymer scaffolds and identified two gelators and one gelator-precursor to be used for analyte signal amplification.

Part 2 of this thesis focuses on online homework in higher education with an emphasis on systems used in chemistry courses. One advantage of online homework is students receive immediate feedback, regardless of instructor time. While a number of organic chemistry homework platforms existed, we found that they did not contain the types of questions we use to assess our students learning, which are open-ended and literature-based. In chapter 5, we describe our efforts to create a feedback-driven online homework resource aligned with our course assessments. We describe a method with which undergraduate students were able to create usable questions with written feedback in an online platform. The questions were then released to incoming students as an optional resource. In chapter 6, we investigate whether our resource was effective in promoting student learning. We observed low student participation due to resource cost and student time constraints, but some evidence of improved course performance in students who used the resource. We propose future research to assess student interactions with the resource and how these affect course performance.