Superoleophilic and Superhydrophobic Inverse Opals for Oil Sensors

Abstract An inverse opal with both superoleophilic (oil contact angle (CA), 5.1° ± 1.2°) and superhydrophobic (water CA, 153.8° ± 1.2°) properties is fabricated using a phenolic resin (PR) as precursor and poly(styrene‐methyl methacrylate‐acrylic acid) (poly(St‐MMA‐AA)) colloidal crystals as templates. The stopband of the inverse opal can shift reversibly upon sorption of oils, whereby the peak position is a linear function of the refractive index of the adsorbed oil, e.g., a variation in refractive index of 0.02 will result in a stopband shift of 26 nm. Therefore, the inverse opals show a high sensitivity and selectivity for different petroleum oils. Moreover, as‐prepared PR inverse opals show excellent oil‐sensing stability in cyclic sorption experiments, which suggests a promising and economical alternative to traditional oil‐sensing materials, and will provide a new approach to in situ petroleum monitoring and detection.