A colorful oil-sensitive carbon inverse opal

A colorful oil-sensitive carbon inverse opal was fabricated by using poly(St-MMA-AA) colloidal crystals as a template. The color shift upon adsorption of oil was reversible, and was easily visible with the naked eye. The peak positions showed a linear relationship with the refractive indices of the oils. In particular, different oils could be distinguished by the color of the carbon inverse opal with a pore size of 240 nm. The response time of the carbon inverse opal was less than 30 s, which is faster than traditional oil sensors. Moreover, the as-prepared carbon inverse opal showed good oil-sensing stability under cyclic adsorption experiments, which suggests that it is a promising and economical alternative to traditional oil-sensing materials, providing a new approach to in situ oil monitoring and detection.