Imprinting as a versatile platform for sensitive materials – nanopatterning of the polymer bulk and surfaces

Fast and technologically available methods for chemical sensor layer production are gaining increasing interest. Imprinting methods fulfil this requirement by generating (sub)nanopatterned polymer materials containing selective interaction sites. These are created by the analyte-to-be which is used as template during synthesis of the sensitive material. Polystyrenes for detecting organic solvent traces in water can be tuned in selectivity, thus the resulting layer discriminates between compounds differing in one methyl group. A toluene imprint, e.g. favours toluene over xylene and benzene, respectively, by a factor of 8–10. Additionally, the materials can distinguish between geometric isomers as shown for the o- and the p-xylene imprint, respectively, where each favours the particular template compound. Especially the sensitivity of an imprint can be substantially increased with e.g. double templates, as shown for PAHs. Sensor signals are augmented this way by a factor of up to four, therefore shifting the lower detection limit by the same amount. When applying soft surface imprinting techniques, even delicate templates, such as the parapox virus ovis, lead to surface imprints that are capable of re-incorporating them. This opens up the way for fast on-line analysis of this class of analytes.