Surfactant-modified DNA and Conjugated Polymers for Photonic Applications

More and more researchers look upon biopolymers to combine with or as a substitute for synthetic polymers to attain materials with improved and interesting properties. The majority of this dissertation talks about exploring a variety of DNA sources in preparing the DNA-surfactant complex, its combination with conjugated polymers and its application in optoelectronic devices. Chapter 3. Currently, salmon is the most common source of the DNA sodium salt used in making the DNA-CTMA complex. Other DNA sources, such as herring and onion, were investigated as well as low and high molecular weight salmon DNA. The energy transfer efficiency between the donor dye, coumarin 480 (Cm 480) and the acceptor dye, 4-[4-(dimethylamino)styryl]-1-docosyl-pyridinium bromide (Hemi 22) was quantified and compared between the various DNA sources and molecular weights. Chapter 4. The first use of the polar fluorinated solvent 1,1,1,3,3,3-hexafluor-2-propanol (HFIP) as a processing solvent for DNA-surfactant complex is reported. Films of DNA-CTMA casted from HFIP resulted in higher dielectric constant values and lower dissipation factor compared to films casted from butanol (BuOH). The observed dielectric properties were due to the solvent effect on the DNA-CTMA polymer conformation as well as the DNA secondary structure. Chapter 5. The biopolymer DNA-CTMA and its blends with the polymer polyaniline were characterized for their dielectric properties. UV-Vis spectroscopy confirmed the slightly expanded coil conformation of acid doped polyaniline and the tight coil conformation of the emeraldine base while circular dichroism ascertained the B-conformation of the DNA The plasticizing effect of polyaniline seen on the DSC was verified through X-ray diffraction results that showed the increase in the inter-strand distance between DNA-CTMA. The blends show a promising potential for capacitor applications. Chapter 6. Optimization of the monomer in situ approach for electrochromic device preparation was done where various salts in the polymer gel electrolyte were examined to prevent local nucleation spots and streaking observed when using this method. The lithium salts gave the highest optical contrast and fastest response time in the electrochromic devices assembled using poly (3,4-ethylenedioxythiophene) (PEDOT) and poly(2,2-dimethylpropylenedioxythiophene) (2,2-ProDOT) as electrochromic layer. Other classes of salts studied were ionic liquids and ammonium salts.