Monitoring Fluorescence Response of Amphiphilic Flapping Molecules in Compressed Monolayers at the Air–Water Interface

• Published in: Chemistry, an Asian journal Vol. 14; no. 16; pp. 2869 - 2876
• Main Authors: Nakanishi, Waka, Saito, Shohei, Sakamoto, Naoki, Kashiwagi, Akihiro, Yamaguchi, Shigehiro, Sakai, Hideki, Ariga, Katsuhiko
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 16.08.2019
• Subjects: Biomolecules; Chain dynamics; Chemistry; Compressed air; Fluorescence; Interfaces; Mechanical stimuli; Molecular motion; Monolayer; Polarity; Rotors; Viscosity; Viscosity probe; Interfaces; Fluorescence; Monolayer; Mechanical stimuli; Viscosity probe
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201900769

The air–water interface, which is the boundary of two phases with a large difference in polarity, gives a distinct environment compared with bulk water or air. Since the interface provides a field for various biomolecules to work, it is important to understand the molecular behaviors at the interface. Here, polarity‐independent flapping viscosity probes (FLAP) equipped with hydrophobic/hydrophilic substituents have been synthesized and studied at the air–water interface. In situ fluorescence (FL), which is related to the internal motion and orientation, of three different FLAPs were investigated at the interface, and the internal motion of the molecule was indicated to be suppressed at the interface. In addition, the molecular response was compared with that of conventional viscosity probes (molecular rotors), which indicates the different behaviors of FLAP probably due to the distinct molecular orientation as well as molecular motion. A different type of behavior: The fluorescent response of flapping viscosity probes was monitored in compressed monolayers, indicating the different behaviors from those of conventional fluorescent molecular rotors.