Amphiphilic Anthracyl Crown Ether. A Langmuir and Langmuir-Schaefer Films Study
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- 作者：Shaopeng Wang ; Qianhui Zhang ; Probal K. Datta ; Robert E. Gawley ; and Roger M. Leblanc
- 刊名：Langmuir
- 出版年：2000
- 出版时间：May 16, 2000
- 年：2000
- 卷：16
- 期：10
- 页码：4607 - 4612
- 全文大小：197K
- 年卷期：v.16,no.10(May 16, 2000)
- ISSN：1520-5827
文摘
As a potential material for use in optical fiber fluorescence sensors for rapid detection of saxitoxin,9-(monoaza-18-crown-6-methyl)-10-hexadecylanthracene (CAC16) was synthesized, and the interfacial andspectroscopic properties of the Langmuir monolayers and Langmuir-Schaefer films of CAC16 were studied.The surface pressure-area and surface potential-area isotherms of CAC16 on different subphases wereobtained. An increased limiting molecular area was observed on a pH 2 subphase. In situ fluorescenceemission spectra (
ex = 366 nm) of the CAC16 monolayer showed a broad fluorescence band on a pH 2subphase but none on a pure water subphase. Mixed monolayers of CAC16/C20 (arachidic acid) on a purewater subphase showed an increased fluorescence emission intensity of anthracene with an increase inthe proportion of C20. This suggests that the low fluorescence activity of the pure CAC16 monolayer couldbe caused by self-quenching due to the high concentration of CAC16 at the interface. In a mixed monolayer,C20 acts as a two-dimensional solvent to dilute CAC16 and diminish the self-quenching, thus recoveringthe fluorescence activity of CAC16. When CAC16 was mixed with C18OH (stearyl alcohol), the monolayersshowed no fluorescence signal, regardless of the C18OH content. Analysis of the surface pressure-areaisotherms showed that CAC16 is not miscible with C18OH. Langmuir-Schaefer films of CAC16/C20 showedbetter anthracene emission spectra than the monolayers at the air-water interface.
ex = 366 nm) of the CAC16 monolayer showed a broad fluorescence band on a pH 2subphase but none on a pure water subphase. Mixed monolayers of CAC16/C20 (arachidic acid) on a purewater subphase showed an increased fluorescence emission intensity of anthracene with an increase inthe proportion of C20. This suggests that the low fluorescence activity of the pure CAC16 monolayer couldbe caused by self-quenching due to the high concentration of CAC16 at the interface. In a mixed monolayer,C20 acts as a two-dimensional solvent to dilute CAC16 and diminish the self-quenching, thus recoveringthe fluorescence activity of CAC16. When CAC16 was mixed with C18OH (stearyl alcohol), the monolayersshowed no fluorescence signal, regardless of the C18OH content. Analysis of the surface pressure-areaisotherms showed that CAC16 is not miscible with C18OH. Langmuir-Schaefer films of CAC16/C20 showedbetter anthracene emission spectra than the monolayers at the air-water interface.