Date of Award

5-2021

Degree Type

Honors College Thesis

Academic Program

Polymer Science and Engineering BS

Department

Polymers and High Performance Materials

First Advisor

Yoan Simon, Ph.D.

Advisor Department

Polymers and High Performance Materials

Abstract

Upconversion (UC) is the conversion of low energy light to higher energy light. It is utilized for a broad range of applications such as solar energy harvesting, microscopy of cellular biology, and cancer therapy. Specifically, triplet-triplet annihilation UC (TTA-UC) involves two dye species, a sensitizer and an annihilator, which are capable of upconverting noncoherent light such as sunlight. Traditionally, TTA-UC is achieved in solution, rubbers, or glasses, however, this work probes the capabilities of a thermoplastic elastomer (TPE) matrix to examine the effect of phase-separated morphology on the energy transfers necessary for TTA-UC. The system herein consists of poly(styrene-isobutylene-styrene) (SIBstar) as the TPE matrix, palladium octaethylporphyrin (PdOEP) as the sensitizer, and diphenyl anthracene (DPA) as the annihilator. Several processing methods (solvent-casting, spin-coating, melt-processing) were explored to incorporate the dyes homogenously within the TPE. However, only low levels of UC were detected in the latter. Assuming aggregation of DPA to be the main hindrance to UC in SIBstar, covalent attachment of DPA to the styrenic portion of the SIBstar backbone was performed. The resulting DPA modified SIBstar (DPAstar) proved unprocessable. While UC was not achievable in these systems, the ability to control and modulate UC through copolymer morphology remains intriguing for the development of flexible, robust, and efficient polymer materials.

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