Profluorescent nitroxide sensors for monitoring photo-induced degradation in polymer films

• Published in: Sensors and actuators. B, Chemical Vol. 241; pp. 199 - 209
• Main Authors: Lussini, Vanessa C., Colwell, John M., Fairfull-Smith, Kathryn E., Bottle, Steven E.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 31-03-2017; Elsevier Science Ltd
• Subjects: Actuators; Alkynes; Copolymers; Damage detection; Degradation; Fluorescence; Infrared spectroscopy; Monitors; Photodegradation; Polymer films; Polymers; Profluorescent nitroxide; PTMSP; Sensitivity enhancement; Sensors; TOPAS; Degradation; PTMSP; Fluorescence; TOPAS; Profluorescent nitroxide
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2016.09.104

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•Perylenediimide fluorophores linked to nitroxides represent new probes to monitor photo-oxidative degradation in organic polymer materials.•The fluorescence emission from fluorophore-nitroxide probes provides a highly sensitive response correlated to the level of photo-induced radical-mediated damage in organic materials.•Fluorescence emission from the probes provides a measure of exposure derived degradation and damage that enables new methods to monitor and predict the lifetime of protective coatings and structural organic materials.
A range of profluorescent nitroxides (PFNs) were tested as probes to monitor photo-induced radical-mediated damage in polymer materials. The most stable and sensitive probe of the PFNs tested was an alkyne-linked perylenediimide PFN, 6b, with napthalimide and 9,10-bis(phenylethnyl)anthranene-based versions giving lower stability and sensitivity. Results from photo-ageing of poly(1-trimethylsilyl)-1-propyne (PTMSP) and the ethylene norbornene copolymer (TOPAS®) films doped with PFN probes demonstrated that sensors employing these support materials deliver significantly enhanced sensitivity compared to traditional techniques used to monitor photo-oxidative degradation of polymers, such as infrared spectroscopy. This enhanced sensitivity for detecting polymer damage improved methods for the determination of the serviceable application lifetime of polymers.