Ultra-fast switching surface

About

Scientists at Durham University have developed a new range of solvent cast polymer coatings exhibiting the highest switching parameters of any known materials as well as exhibiting ultra-fast switching speeds. Smooth copolymer–fluorosurfactant complex films are found to produce optically transparent surfaces with fastswitching behavior. Equilibration of high oil contact angle (hexadecane = 80°) and low water contact angle (<10°) occurs within 10 s of droplet impact. The extremely low water contact angles are highly desirable for anti-fogging applications. Oil-water separation technologies. Due to the frequency of off-shore oil spillages and the expansion of fracking, the separation of oil and water remains an important and unmet challenge for the oil industry. The favoured option of using filters with oleophobic–hydrophilic surfaces, where the oil-based contaminants are repelled and water passes through, have so far failed to make it into widespread usage. Commercial adoption has been constrained by a series of known limitations of available film materials: It can take several minutes for water to penetrate through a fluorinated top layer, resulting in a surface that is initially hydrophobic. Materials often exhibit an inadequate level of oil repellence. Production may involve multi-step processes, such as pulsed plasma deposition, that are unsuitable for many applications. The new surface coatings overcome these key limitations opening up a new route for rapid commercial implementation. When sprayed as a single step process on to a steel mesh we have recorded separation efficiencies exceeding 98%.