New method manufactures thin films using water and oil

A new technology can quickly produce thin films using just water and oil in one minute. This innovation comes from Professor Kang Hee Ku and her team at UNIST, who developed a process for making catalytic thin films by using dispersed oil droplets in water. The process involves nanomaterial precursors that are attached to the surface of oil droplets. These droplets float on water, where the precursors assemble into a thin film. When hydrogen peroxide is added, it causes gas bubbles to form, lifting and organizing the precursors into a thin film in less than a minute. This method allows for precise control over the film's thickness, which can be adjusted from 350 micrometers, and can create films covering areas up to 100 square centimeters. The resulting films have a porous structure, high strength, and flexibility. The transfer process of the thin films to other surfaces is also improved. Typically, transferring high-quality films can damage them, but this new technique does it without harm. Experiments showed successful transfer onto various substrates, including those with complex patterns. The research team used carbon nanomaterials coated with platinum to create flexible electrodes. These electrodes maintained consistent conductivity, capable of powering a small light bulb even when bent repeatedly. The findings were published in ACS Nano. Professor Ku stated that this technology is a significant improvement, inspired by Pickering emulsions often used in cosmetics. These emulsions help lower surface energy by using solid nanoparticles instead of traditional surfactants. The team’s approach makes it easy to choose different types of nanoparticles and works for various substrates, which could benefit the creation of flexible electrodes, catalysts, and energy storage devices.