A Naked-Eye-Detection Alcohol Dipstick: Electrospun Hierarchical Structured Fluorine-Rich Nanofibrous Membranes

To certify alcohol usage in industrial and daily life, a simple, environmental-tolerance, and easy-to-identify alcohol dipstick (AD) that use a hierarchical structured fluorine-rich nanofibrous membrane is devised. This membrane is opaque before alcohol treatment due to light scattering caused by mismatched refractive index (RI) between nanofiber and air, but becomes reversibly translucent after alcohol wetting for the first time through alcohol-induced partial interfibrillar dissolution of the hierarchical membrane. Subsequently, the membrane, as an alcohol dipstick, possesses rapid transmittance response after repeated treatment of alcohol, as well as monitors both alcohol vapor and trace amount of alcohol in water. The hierarchical membrane itself serves as both an alcohol indicator and display; it does not require harsh conditions, sophisticated instrument or experienced operator, and functions even after rinse in alcohol, sandpaper abrasion, ultrasonic washing in alcohol for several cycles in a manner that existing AD cannot. It also does not involve any chemical reaction because it operates through inherent properties and could be identified by naked-eye.