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.

Recent research progress in wettability of colloidal crystals

“…In this case, hydrogen bonding is suppressed due to deprotonation of COOH to COO  . Additionally, many other works have also demonstrated the fabrication of surface with special wettability by combining its surface chemical composition and its roughness structure, for example, Li et al fabricated a superhydrophobic and superoleophilic phenolic resin [39]; Chen et al fabricated a superhydrophobic polyimide inverse opal [40].…”

High effective sensors based on photonic crystals

“…An inverse opal with both superoleophilic and superhydrophobic properties is fabricated using a phenolic resin as precursor and colloidal crystals as templates. The stop band 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 the refractive index of 0.02 will result in a stop band shift of 26 nm [63]. Moreover, a colorful oil-sensitive carbon inverse opal was fabricated and the color shift upon absorption of the oil was reversible, and was easily visible to the naked eyes Figure 4 Schematic illustration of the opal/inverse opal films which are sensitive to different solutions.…”

Bottom-Up Assembly and Applications of Photonic Materials

“…Due to their ability to "manage" light over the range of its bandgap [81][82][83], inorganic semiconductor materials such as titania [84][85][86][87][88][89], silica [90][91][92][93], and zinc oxide [94] have all been made into inverse opals and studied extensively. In addition, other materials such as metals [42,80,[95][96][97][98][99][100] and organic materials [101][102][103][104][105] have also been fabricated into inverse opals and investigated.…”

“…Li et al demonstrated the use of inverse opals as oil sensors. They described the reversible shifting of the stop-band which varies as a linear function of the refractive index of the adsorbed oil [103]. Zhang et al described the development of a sensing material made of a crystalline 2D array of colloidal photonic crystal.…”