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

Waka Nakanishi; Shohei Saito; Naoki Sakamoto; Akihiro Kashiwagi; Shigehiro Yamaguchi; Hideki Sakai; Katsuhiko Ariga

doi:10.1002/asia.201900769

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

Chem Asian J. 2019 Aug 16;14(16):2869-2876. doi: 10.1002/asia.201900769. Epub 2019 Jul 25.

Authors

Waka Nakanishi^{1

2}, Shohei Saito^{3

4}, Naoki Sakamoto^{1

5}, Akihiro Kashiwagi⁶, Shigehiro Yamaguchi⁶, Hideki Sakai⁵, Katsuhiko Ariga^{1

7}

Affiliations

¹ World Premier International (WPI) Centre for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, 305-0044, Japan.
² Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, 305-0047, Japan.
³ Department of Chemistry, Graduate School of Science, Kyoto University Kitashirakawa Oiwake, Sakyo, Kyoto, 606-8502, Japan.
⁴ Japan Science and Technology Agency (JST), PRESTO Kitashirakawa Oiwake, Sakyo, Kyoto, 606-8502, Japan.
⁵ Department of Pure and Applied Chemistry, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan.
⁶ Department of Chemistry, Graduate School of Science, Nagoya University, Furo, Chikusa, Nagoya, 464-8602, Japan.
⁷ Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan.

PMID: 31290274
DOI: 10.1002/asia.201900769

Abstract

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.

Keywords: Fluorescence; Interfaces; Mechanical stimuli; Monolayer; Viscosity probe.

Abstract

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