ABSTRACT
In the present paper we report about the Langmuir-Blodgett thin film characterization and organic vapor sensing properties of a novel 1,3-bis(p-iminobenzoic acid)indane (IBI) containing polar carboxylic acid groups. LB film properties of IBI material is characterized by UV-visible spectroscopy, atomic force microscopy, and quartz crystal microbalance. Our results show that high-quality and uniform LB films can be prepared with the transfer ratio of over 0.95. Organic vapor sensing properties are studied using quartz crystal microbalance measurement system. IBI film is found to be significantly more sensitive to benzene and the response of LB sample is fast, large, and reversible. The sensitivity of detection of toluene, ethyl alcohol, and isopropyl alcohol is much smaller than that of benzene. This newly synthesized IBI is a suitable molecule for the fabrication of an LB film and can be regarded as a promising sensing material in the development of a room temperature gas sensor for benzene vapor applications.
Subject(s)
Indans/chemistry , Nanotechnology/instrumentation , Nanotechnology/methods , para-Aminobenzoates , 2-Propanol/chemistry , 4-Aminobenzoic Acid/chemistry , Benzene , Biosensing Techniques , Buffers , Chemistry, Physical/methods , Electrodes , Gases , Kinetics , Membranes, Artificial , Microscopy, Atomic Force , Microscopy, Scanning Probe , Models, Chemical , Motion Pictures , Oscillometry , Pressure , Quartz , Spectrophotometry , Surface Properties , Temperature , Time Factors , Toluene/chemistry , Ultraviolet RaysABSTRACT
Non-centrosymmetric Z-type Langmuir-Blodgett (LB) films were prepared by transferring a calix[4] acid monolayer from a subphase of Millipore water (18 Momegacm(-1)) onto aluminised glass substrates. Electrical measurements were performed at room temperature on LB films with a sandwich structure comprising a 50 nm thick thermally evaporated aluminium film. A pyroelectric figure of merit of 2.23 microC m(-2)K(-1) is reported for this LB system. The low voltage value of conductivity is 1.82 x 10(-12) Sm(-1). The electrode-limited Schottky effect is responsible for the conduction mechanism at a relatively high field due to the dc bias and the barrier potential height is determined to be 1.72 eV. The ac conductance for both samples shows a typical power law dependence with a value of approximately 0.86 for the exponent.
