Highly Sensitive Dissolved Oxygen Sensor with a Sustainable Antifouling, Antiabrasion, and Self-Cleaning Superhydrophobic Surface

Long-term sensing of dissolved oxygen in aqueous solution always suffers from adherence of algae, barnacles, and clams and formation of biofilms on the sensor surface, which strongly influences the diffusion of oxygen into the sensor film. Metabolism of these adhered species consumes oxygen and causes bias on sensor readout. Therefore, commercial sensors are equipped with mechanical brushes to constantly clean the sensor surface, which significantly complicates the sensor design and causes damage to the sensor surface. In addition, extra energy storage and mechanical structures are required, which make an optical sensor bulky and limit its service life. We have developed a robust and highly sensitive dissolved oxygen sensor with good mechanical stability and self-cleaning capability. The sensor was fabricated by doping oxygen-sensitive probe PtTFPP with superhydrophobic coating. The 3 to 5 nm micro/nanostructures formed from silica sol were solidified with silicone resin, which endowed the sensor film with excellent mechanical stability. The sensor film exhibits antifouling, antiabrasion, and self-cleaning properties. There is no need of mechanical brushes to clean sensor surfaces, which greatly simplifies the sensor design. Owing to the porous structure, the sensor shows high quenchability, with I0/I100 of 77. All these features guarantee that the sensor could be used in harsh and dirty conditions for long-term monitoring of dissolved oxygen concentration.