BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows structures and formulas of ILs.
FIG. 2 is a graph showing frequency change vs. concentration of the IL/QCM sensor exposed to ethanol (square), heptane (triangle), benzene (star) and dichloromethane (circle) at 120° C.
FIGS. 3A and B are graphs showing the frequency changes of the IL/QCM sensors exposed to 80% ethanol, heptane, benzene and dichloromethane at various temperatures. FIG. 3A shows Δf as a function of T of ionic liquid P66614OMS. FIG. 3B shows Δf as a function of T of ionic liquid P6666OCS.
FIGS. 4A and B are AFM images of a polished Au QCM surface (FIG. 4A), and after it was modified with IL thin film (FIG. 4B). Contact mode.
FIG. 5 is a graph showing AR % vs. temperature curve.
FIG. 6 illustrates three ATR-FTIR spectra, A, B and C, on a single plot. The graphs show the ATR-FTIR spectra of ionic liquid P66614OCS film (Spectrum A), ethanol vapor exposed to bare substrate (Spectrum B) and to P66614OCS film covered substrate (Spectrum C).
FIG. 7 is a graph showing normalized relative response pattern of IL sensors (coated with bmiOCS, P66614 DBS, P66614OMS, and P66614OCS) for ethanol, heptane, CH2Cl2, and benzene at 120° C. The signals are normalized by the weight of IL coatings and the vapor pressure of each analyte.
FIGS. 8A and B show immobilization via electrostatic interaction between cations/anions of ILs and SAMs.
FIG. 9 is a graph showing Nyquist plots of EIS study of 1 mM Fe(CN)63−/4− in 0.1 M NaClO4 on a gold electrode modified by soaking sequentially in: 1 mM HS(CH2)10COOH/THF solution for 3 days (open triangle), 0.1 M KOH for 15 min (solid circle), 5 mM IL P66614 DBS/EtOH solution for 2 days (solid triangle) solutions and ethanol (open square). The gold electrode was prepared by annealing in a gas/O2 flame, to produce a smooth surface with predominant Au(111) facets. Note: after each treatment, the gold electrode was rinsed in ethanol (EtOH) for 24 hours before EIS study was carried.
FIG. 10A illustrates layer-by-layer deposition of polysolfonate styrene having negative (−) charges, and ionic liquid having positive charges (+), on a substrate. FIG. 10B illustrates an electrode having PVF with charged groups (Fc+) as a polymer frame embedded with ionic liquid.
FIG. 11 shows chemical structures of thiolated zwitterionic liquids (I, III) and primary zwitterionic liquids (II, IV).
FIGS. 12A and 12B are schematics of the layer-by-layer deposited zwitterionic liquid film structure (FIG. 12A) and polyionic liquid film structure (FIG. 12B).
FIG. 13 is a drawing showing a schematic of a sensor array of QCM devices having different ionic liquid (IL) coatings and response pattern reorganization.
FIG. 14 illustrates a prototype QCM 4 channel device (left) with four QCM sensors in one monolithic quartz (lower left) in air to give a four channel output from the four. QCM sensors set up as an array.
FIG. 15 shows the flow system setup for characterization of the PAN/IL sensors.
FIG. 16 shows isotherms from different ILs.
FIG. 17A shows the amount of PAN deposited vs. polymerization time; FIG. 17B shows Δf vs. polymerization time.
FIG. 18 shows the structures of PAN.
FIG. 19 shows the methane sensing results of the PAN films at different oxidation states before and after the immobilization of IL.
FIG. 20 shows the frequency change of same PAN film at different state: doped and undoped, 10% methane.
FIG. 21A shows FTIR of PAN and PAN+bmiCS; FIG. 21B shows FTIR of bmiCS and PAN+bmiCS subtract PAN.
FIG. 22 shows scheme 2.
FIG. 23A shows the spectra of methane on ZeSe and on PAN; FIG. 23B shows the spectra of methane on ZnSe and on PAN+IL.
FIG. 24 shows the UV-Vis of PAN film soaked in IL solution.
FIG. 25 shows scheme 3.
FIG. 26 shows the Δf caused by IL loading as a function of [bmiCS].
FIG. 27A shows the Δf caused by methane absorption vs. [bmiCS], and FIG. 27B shows Δf caused by methane absorption vs. methane concentration of PAN films before and after treated in IL solutions.
FIGS. 28A and 28B shows the time course response (Δf) curve of PAN/bmiCS (0.2) film response to methane with varied concentration at room temperature.
FIGS. 29A and 29B shows the time course response (Δf) curve of PAN/bmiCS (0.002) film response to methane with varied concentration at room temperature.
FIG. 30A shows Δf vs. time at various temperatures, and FIG. 30B shows the Δf plotted vs. temperature, at methane concentration of 3%.
FIG. 31A shows ln(Δf) vs. 1/T, and FIG. 31B shows the ln(Δf) vs. ln(T).
Patent Application
20070231918
