Development of ultrathin molecularly imprinted polymer films for polyaromatic hydrocarbon sensing

Abstract

Produced water is one of the pollutants produced at a large scale during offshore oil and gas activities. Wastewater which has been separated from oil and gas during production can be defined as produced water. Although produced water contains a wide variety of toxic chemicals, polycyclic aromatic hydrocarbons (PAHs) within produced water have received considerably greater attention due to their capability of causing long term toxic effects at the individual level in the marine environment. Due to the adverse effect of PAHs (organic pollutants) on the environment and lives, accurate detection and monitoring of PAHs is required before discharging the produced water into the sea. Molecularly imprinted polymers (MIPs) can capture analytes such as PAHs, and when coupled with a detection mechanism, can act as sensors for those pollutants. These films are suitable for remote sensing because they can effectively concentrate the analyte in situ. To combine MIPs with an optical sensing element, it can be useful to create them in an ultrathin film format, which is also important for portability to remote areas. One way to achieve a uniform film with nanoscale thickness is through spin coating. In this study, ultrathin film MIPs have been prepared following a new procedure. Various processing parameters including spin time and speed have been explored to determine their effects on MIP film structure as well as their removal and uptake of template molecules. Raman spectroscopy was used for the detection of the analyte, and atomic force microscopy was used to characterize the films’ morphology as well as to measure the thickness of the films, which ranged from 300 nm down to 4 nm. Our findings have determined that different spin speeds produce different film morphology. Furthermore, thinner films showed more homogeneity and reproducibility.