Photolithographic Micro-patterning of Polymers for Optical Applications

Research output: ThesisMaster's Thesis

Abstract

This work deals with the synthesis and characterization of photoreactive polymers and their potential application in optics and opto-electronics. First, polymers bearing phenyl or naphthyl ester groups are investigated. These polymers are easily accessible by polymer analogous esterification of commercially available poly(4-vinylphenol). Both polymers, poly(4-vinylphenyl benzoate) (PVP-BZ) and poly(4-vinylphenyl 1-naphthoate) (PVP-NA), undergo a Fries rearrangement upon exposure to UV light. This leads to a change in the refractive index up to Δn = +0.036. Refractive index patterns can be generated using photolithographic techniques as shown by optical microscopy using a phase contrast set-up for visualization. Patterned films of PVP-BZ and PVP-NA with a resolution of 1 μm are obtained by the use of a mask aligner. The formation of hydroxyl ketone groups upon UV irradiation also provides the opportunity of selective post-exposure reactions, including the immobilization of different fluorescent dyes in the illuminated areas. In combination with lithographic processes fluorescence patterns with bright luminescence are obtained. The difference in UV absorbance of these polymers can be employed for the design of a dual-layer assembly. This allows selective patterning of each layer by the choice of the specified wavelength. Thus, these materials are of interest for multi-layer optical data storage applications. In addition, (±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylicbis-(4-thiocyanatomethyl)benzylester is synthesized and polymerized via ring-opening metathesis polymerization (ROMP). The attached SCN-groups undergo a conversion to NCS-groups upon UV irradiation. This provides the possibility of selective surface functionalization by physical mixing with a fluorene-based electroluminescent polymer followed by photolithographic patterning and post-modification with a fluorescent dye. Due to Förster resonance energy transfer (FRET), tuning of the emission color can be achieved.

Details

Translated title of the contributionPhotolithographische Mikro-Strukturierung von Polymeren für Optische Anwendungen
Original languageEnglish
QualificationDipl.-Ing.
Awarding Institution
Supervisors/Advisors
Award date17 Dec 2010
Publication statusPublished - 2010