Organic materials such as polymer films surround us in many everyday applications ranging from food packaging and smartphone displays to medical purposes. One of their main usage scenarios is the thin, lightweight, and easy processable encapsulation to protect a particular target from molecular oxygen. Hence, the oxygen diffusion properties in these polymer films represent a key parameter.
This work demonstrates a new method to determine and model the oxygen distribution in thin polymer films using light. It provides a significant advantage over many common methods since no vacuum machinery is needed. The working principle is based on the phosphorescent emission of an organic dopant which is quenched in the vicinity of molecular oxygen at room temperature.
The model system used in this study consists of a polystyrene layer, which is doped with PtOEP (Platin(II)-2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin) and covered with a barrier layer of Ex-cevalTM. The oxygen concentration in the doped polystyrene film can be locally depleted under excitation with 365 nm UV light. To determine the oxygen diffusion coefficient, a concentration gradient is created and the time evolution of the luminescent pattern is recorded with a CCD-camera. The recorded data is reconverted to oxygen concentration equivalents and the impact of photoconsumption during the recording process is eliminated, before fitting it with a diffusion simulation. The result reveals a significant dependency on the processing conditions of the film, i.e. D = (1.49 ± 0.08) × 10−7 cm^2/s for unannealed and D = (0.71 ± 0.09) × 10−7 cm^2/s for an-nealed samples. The values lie well in the range reported in the literature.:Problem
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| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:85537 |
| Date | 30 May 2023 |
| Creators | Kantelberg, Richard, Achenbach, Tim, Kirch, Anton, Reineke, Sebastian |
| Contributors | Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:conferencePoster, info:eu-repo/semantics/conferencePoster, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | urn:nbn:de:bsz:14-qucosa2-855326, qucosa:85532 |
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