A pyrene-capped terthiophene of cholesteryl derivative (CholG-3T-Py) was designed, synthesized, and utilized for the fabrication of a fluorescent film. Unlike the commonly adopted direct-coating method, the film was fabricated by the physical immobilization of the fluorophore, CholG-3T-Py, onto a glass plate surface via preformed low-molecular-mass gelator (LMMGs)-based molecular-gel networks. The photophysical behavior of the film as prepared and its sensing performances to nitrobenzene (NB) were conducted after activation with toluene. It was found that the film as prepared and activated is sensitive to the presence of NB, and the sensing process is fully reversible. Furthermore, the effects of commonly found interferents, including structural analogues, raw materials, which are commonly used for the production of NB, and other nitroaromatics (NACs), on the sensing process were also tested. It was shown that only aniline and phenol possess slight interference. The present work not only extends the applications of LMMGs-based molecular gels but also provids a new approach for preparation of micro- and nano-structure-based fluorescent sensing films.

A self-assembled monolayer (SAM)-based fluorescent film was designed and prepared by chemical immobilization of a novel oligo(p-phenylene- ethynylene) (OPE) with cholic acid moieties at the ends of its side chains (Film 1). As a control, a similar film, Film 2, of which OPE brings no side chains, was also prepared. The structures of the films were characterized by contact angle, XPS, ATR-IR and fluorescence measurements. Fluorescence studies revealed that the emission of Film 1 is sensitive to the presence of trace amount of some inorganic acids in acetone, such as HCl, H(2)SO(4), HNO(3), and H(3)PO(4), etc., whereas the acids as studied showed little effect on the emission of Film 2. The difference in the sensing performances of the two films have been rationalized by considering presence or absence of a possible cavity, a substructure appearing above the OPE adlayer which is something like a dimer of cholic acid (CholA) formed at specific environment.

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