Macroporous Polytetrafluoroethylene Film with a Reusable Matrix and Its Application as the Microreactors

This work reports a simple and efficient preparation method of an inverse-opal-like macroporous polytetrafluoroethylene (IO-PTFE) film with a reusable matrix. At first, the pH-responsive poly(acrylic acid) (PAA) is grafted on the PTFE latex particles induced by γ-ray radiation. The stability of PAA grafted PTFE latex particles (PTFE-g-PAA) in water decreases in acid aqueous solution. As a result, PTFE-g-PAA particles can coprecipitate with monodispersed polystyrene (PS) microspheres from the acidic aqueous dispersion to form a composite particulate film. After the composite particulate film is etched with toluene to remove PS microspheres, a self-stand inverse-opal-like macroporous PTFE film can be successfully obtained. The macroporous PTFE film can be applied as the microreactor to synthesize uniform TiO₂ particles. The separation of TiO₂ microparticles and the recycle of PTFE-g-PAA particles can be simultaneously achieved simply in water by means of ultrasonification. The prepared TiO₂ microparticles also show good photocatalytic performance. This work opens a new thought to prepare special macroporous polymeric materials, and expands the microsynthesis of inorganic or organic microparticles by taking advantage of polymeric macroporous materials.