First observation of fluorescence self-quenching in Langmuir films

✍ Scribed by George R. Ivanov

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 425 KB
• Volume: 193
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)85637-p

✦ Synopsis

Systematic investigations of dipalmitoyl-phosphatidylethanolamine

head labelled with nitrobenzoxadiazole (DPPE-NBD) are performed both on monolayers at the air-water interface and deposited on solid substrates as Langmuir-Blodgett films. This dye compound is frequently used as a fluorescent additive in fluorescence microscopy investigations. It is also a suitable model compound. We present experimental evidence for the self-quenching of the fluorescence when higher-order domains of the dye are formed at the air-water interface. A coexistence of two completely different types of domains at the phase coexistence region for a single-component system is observed. From small-angle X-ray diffraction, pressure-area isotherms and molecular space filling models, an average tail tilt angle of 31' towards the normal to the substrate surface is estimated when deposition is carried out at 50 mN/m. These data, together with information from polarized FTIR spectra, support a conclusion of a decrease of tail tilt and increase of the order of the deposited films on increase of the deposition pressure.