Tunable Nanocellular Polymeric Monoliths Using Fluorinated Block Copolymer Templates and Supercritical Carbon Dioxide

A novel, innocuous method which utilizes carbon dioxide to fabricate optically transparent nanocellular polymeric materials using a fluorinated block copolymer as the template is reported. The CO2-soluble fluorinated blocks effectively localize CO2 in the nanoscopic domains. At 0 °C, with slow depressurization, the block copolymer exhibits CO2-pressure-tunable nanocells of diameters between 10–30 nm, number densities of ∼1016 cells cm–3, and porosities of up to 50% (see Figure).