Characterization of functional states in nicotine- and cotinine-imprinted poly(4-vinylphenol) films by nanoindentation

Thin, imprinted poly(4‐vinylphenol) (PVP) films were produced by spin coating using nicotine or its metabolite, cotinine, as template molecules. The template molecules were extracted from these films and later reloaded (or cross‐loaded) from solution. Depth sensing nanoindentation was applied to measure the nanomechanical properties of the imprinted polymer films. Changes in the nanomechanical properties were correlated to the functional state of the imprinted polymer, allowing identification of the films in their “as produced” state, “template removed state or “reloaded” state. In addition, the nanomechanical properties were capable of identifying which of the two template molecules were inserted in to a film. Reinsertion of a template molecule into a “template removed” film was found to increase the nanohardness over the values recorded for the “as produced” film. This behavior was discussed in terms of the hydrogen bonding characteristics of the materials (through density functional calculations) and the physical properties of poly(4‐vinylphenol) coatings. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012