Conjugated polymer semiconductors have received substantial attention for providing a path to low cost manufacturing of electronics such as organic field-effect transistors, light emitting diodes, and solar cells. This work explores the electronic and structural effects of doping colloidal poly(3-hexlythiophene) (P3HT) nanofibers in non-aqueous solution. Doping injects charge carriers into the organic semiconductor and allows for modulation of electrical and optical properties. In solution, increasing dopant concentration also typically leads to uncontrolled polymer aggregation. In this work, we will demonstrate that doping and colloidal stability can be obtained for self-assembled P3HT nanofibers. This work characterizes the conductivity, structure, and optical properties of P3HT nanofibers as a function of dopant concentration and dopant molecular structure. These findings contribute to improved development of transparent thin films for organic electronics by achieving both solution stability and increased conductivity.

Continued advances in energy technologies have allowed for the increased utilization of renewable energy sources. However, energy storage is needed to provide power during peak hours. Flow batteries offer a convenient solution to the problem of storing large amounts of energy while remaining relatively cost efficient. One of the most expensive parts of a flow battery is the proton conducting membrane that separates the two halves of the battery cell. The current state-of-the-art membrane is Nafion, which can be expensive to produce. The goal of this project is to create a membrane with characteristics that can rival those of Nafion but that can be produced using cheaper materials. Towards this end we are utilizing sodium silicate solutions to create flow battery membranes. Two main characteristics of these membranes were studied: 1) proton conductivity, which is essential to current flowing through the battery and 2) ion permeability, which dictates the rate at which the ions in the two halves of the battery cell mix and the battery quality deteriorates. Initial testing for proton conductivity revealed that the experimental membranes were performing within the same order of magnitude as Nafion. However, the experimental membranes showed high permeability relative to Nafion. Future work will focus on isolating variables that affect pore size and polydispersity in the synthesized membranes in order to size exclude redox ions from permeating the membrane while retaining effective proton conductivity.

The conventional decaffeination processes consume a lot of energy and use many chemical solvents that can be harmful to both the environment and human health. Although there are four main methods of decaffeination, they all consume high amounts of energy and tend to degrade the taste of the decaffeinated coffee; some processes even use harmful chemicals such as methylene chloride. To address this problem, natural clay minerals are chosen as the adsorbents to extract caffeine from coffee beverages due to their unique micro and nano structures. Selective caffeine adsorption can be achieved by engineering the clay structures, including methods of interlayer spacing control, ion exchange, edge sites modification, secondary structure control, and structural polymerization. Three clay minerals have been tested, which are laponite, bentonite, and zeolite Y. For all three clay materials tested, they initially do not show any caffeine adsorption. However, with different engineering principles applied, different degrees of caffeine removal are achieved. The best result is 80% caffeine reduction after 2 minutes and 99.6% after 20 minutes in real coffee using 1 gram of clay per 100mL of coffee; this particular result was achieved through clay interlayer spacing control, secondary structure control, and structural polymerization of the bentonite clay. Moreover, with the HPLC analysis, the result showed that the material is fairly selective for the caffeine molecule, and during the decaffeinated coffee taste tests, most of the participants said that decaffeination with clay yield better taste coffee compared to conventional decaffeinated coffee. This new decaffeination process is much faster and versatile since it can reduce much of the caffeine in most of the beverages that contain caffeine in just a few minutes. Clay mineral structural engineering is a very promising technology for selectively removing caffeine molecules and has great potentials for the beverage industry.