A device for detecting an analyte having a substrate, an alignment layer on the substrate, a film having 4-pentyl-4′-cyanobiphenyl on the alignment layer, a flow cell capable of delivering air suspected of containing the analyte to the film, and an apparatus capable of measuring a physical property of the film. A method of detecting an analyte by: providing a device having a substrate, an alignment layer on the substrate, and a film having 4-pentyl-4′-cyanobiphenyl on the alignment layer; exposing the film to air suspected of containing the analyte; and measuring a change in a physical property of the film in response to exposing the film.