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POLYMER MULTILAYER FILMS FOR OPTICAL AND DIELECTRIC APPLICATIONS

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2016, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
Chapter 1: Performance of new polymer nanolayer GRIN system with a high temperature polymer, OKP4HT, was evaluated. A combination of extruded nanolayered GRIN film systems, comprised of a total of five different materials, were combined to produce optical laminates with a high refractive index range, 1.445 – 1.630. The optical performance of a series of varied magnitude GRIN lenses was evaluated. Refractive index distribution and surface profile of the GRIN lenses match the expected designed value. Increasing the lens refractive index range resulted in decreased spherical aberrations following analytical optical predictions. An analytical approach was reported to correlate the polymer material UST to the onset of polymer material loss modulus as measured by DMTA. Thermo-optical interferometry measurements of irreversible lens deformation confirmed the lenses upper service temperature (UST) as 125°C for the OKP4HT/PC system as compared to 75°C for an PMM/SAN17 systems. Chapter 2: Inspired by the soft, deformable human eye lens, a synthetic polymer GRIN lens with an adaptive geometry and focal power has been demonstrated via extrusion and thermoforming of nanolayered elastomeric polymer films. Polymer nanolayered films comprised of two thermoplastic polyurethanes with a refractive index difference of 0.05 were co-extruded via forced assembly technique. The set of thirty nanolayered polymer films exhibited transmission near 90% with each film varying in refractive index by 0.0017 as a result of the nanolayering arrangement. An adaptive GRIN lens was fabricated from a laminated stack of the variable refractive index films with a 0.05 spherical gradient refractive index distribution and mechanically deformability based on mechanical compression of the lens. Variation in the optical properties, 20% variation in focal length and reduced spherical aberration, of the deformable GRIN lens were measured and simulated by placido-cone topography and ANSYS methods. The demonstration of a solid state, dynamic focal length, GRIN lens with improved aberration correction was discussed in contact of potential future implantable devices. Chapter 3: Enhanced dielectric properties were achieved through interface/interphase modulation and biaxial orientation for the poly(ethylene terephthalate)/poly(methyl methacrylate)/poly(vinylidene fluoride-co-hexafluoropropylene) [PET/PMMA/P(VDF-HFP)] three-component multilayer films. Because PMMA is miscible with P(VDF-HFP) and compatible with PET, the interfacial adhesion between PET and P(VDF-HFP) layers was greatly improved. Biaxial stretching of the as-extruded multilayer films induced formation of highly oriented fibrillar crystals in both P(VDF-HFP) and PET. There were several effects resulted from biaxial orientation. First, the parallel orientation of PVDF crystals reduced the dielectric loss from the ac relaxation in a crystals. Second, biaxial stretching constrained the amorphous phase in P(VDF-HFP) and thus the migrational loss from impurity ions was reduced. Third, biaxial stretching induced a significant amount of rigid amorphous phase in PET, further enhancing the breakdown strength of multilayer films. Due to the synergistic effects of improved interfacial adhesion and biaxial orientation, the PET/PMMA/P(VDF-HFP) 65-layer films with 8 vol.% PMMA exhibited the optimal dielectric properties with an energy density of 17.4 J/cm3 at breakdown and the lowest dielectric loss. These three-component multilayer films are promising for future high energy density film capacitor applications. Chapter 4: Advanced film capacitors require polymers with high thermal stability, high breakdown strength, and low loss for high temperature dielectric applications. In order to fulfill such requirements, two polymer multilayer film systems were coextruded via a forced assembly technique. High glass transition (Tg) polycarbonate (HTPC) and polysulfone (PSF) were layered with poly(vinylidene fluoride) (PVDF), respectively. The PSF/PVDF system was more thermally stable than HTPC/PVDF system. For dielectric properties at At high temperatures the PSF/PVDF system exhibited higher breakdown strength and lower hysteresis compared with HTPC/PVDF system. These results demonstrated that PSF/PVDF was a superior system to HTPC/PVDF for high temperature dielectric capacitors.
Eric Baer (Committee Chair)
Andrew Olah (Committee Member)
Gary Wnek (Committee Member)
Donald Schuele (Committee Member)
163 p.

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Citations

  • Yin, K. (2016). POLYMER MULTILAYER FILMS FOR OPTICAL AND DIELECTRIC APPLICATIONS [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1469530841

    APA Style (7th edition)

  • Yin, Kezhen. POLYMER MULTILAYER FILMS FOR OPTICAL AND DIELECTRIC APPLICATIONS. 2016. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1469530841.

    MLA Style (8th edition)

  • Yin, Kezhen. "POLYMER MULTILAYER FILMS FOR OPTICAL AND DIELECTRIC APPLICATIONS." Doctoral dissertation, Case Western Reserve University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1469530841

    Chicago Manual of Style (17th edition)