Polymers and polymerization

Model
Digital Document
Publisher
Florida Atlantic University
Description
Doped electrically conductive polymers are one of the critical materials that have allowed the current technological revolution. Essentially all of today's applications of doped conductive polymers involve vinyl-related polymers. While the application of conductive polymers is rapidly increasing, there is need for additional materials with different electrical behaviors. The current focus is on studying condensation polymers that contain a metal atom and the possibility of undergoing entire chain delocalization of electrons. The different series of organometallic condensation polymers were synthesized by employing interfacial polycondensation technique and characterization of these products were carried out using standard techniques like light scattering photometer, fourier transform infrared spectroscopy (FTIR), matrix assisted laser desorption ionization time of flight mass spectroscopy (MALDI TOF MS) and nuclear magnetic resonance spectroscopy (NMR). The electrical measurements were carried out employing Genrad 1650-B impedance spectroscopy. Prior studies conducted in this area have led to the pathway of looking at two aspects; first, surveying 60 metal-containing polymers that can undergo entire chain delocalization studying the effect of different substituents on their electrical properties and secondly, doping selected candidates employing iodine. The products derived from 2-nitro-1,4-phenylenediamine and N-methyl-1,4- pheneylenediamines with titanocene dichloride exhibited about 10 3 to 10 5 fold magnitude increases in the electrical conductivity on doping with iodine, moving it near conductive region. This increase is dependent on the concentration of the iodine and is cyclic. The results support the starting premise that selected metal-containing condensation polymers can be doped to increase their electrical conductivity.
Model
Digital Document
Publisher
Florida Atlantic University
Description
Professional imaging systems, particularly motion picture cameras, usually employ larger photosites and lower pixel counts than many amateur cameras. This results in the desirable characteristics of improved dynamic range, signal to noise and sensitivity. However, high performance optics often have frequency response characteristics that exceed the Nyquist limit of the sensor, which, if not properly addressed, results in aliasing artifacts in the captured image. Most contemporary still and video cameras employ various optically birefringent materials as optical low-pass filters (OLPF) in order to minimize aliasing artifacts in the image. Most OLPFs are designed as optical elements with a frequency response that does not change even if the frequency responses of the other elements of the capturing systems are altered. An extended evaluation of currently used birefringent-based OLPFs is provided. In this work, the author proposed and demonstrated the use of a parallel optical window p ositioned between a lens and a sensor as an OLPF. Controlled X- and Y-axes rotations of the optical window during the image exposure results in a manipulation of the system's point-spread function (PSF). Consequently, changing the PSF affects some portions of the frequency components contained in the image formed on the sensor. The system frequency response is evaluated when various window functions are used to shape the lens' PSF, such as rectangle, triangle, Tukey, Gaussian, Blackman-Harris etc. In addition to the ability to change the PSF, this work demonstrated that the PSF can be manipulated dynamically, which allowed us to modify the PSF to counteract any alteration of other optical elements of the capturing system. There are several instances presented in the dissertation in which it is desirable to change the characteristics of an OLPF in a controlled way.