Fluorinated colloidal emulsion of photochangeable rheological behavior as a sacrificial agent to fabricate organic, three-dimensional microstructures.

Three-dimensional organic microfabrication, an emerging technology, faces the challenge of lacking a sacrificial agent (SA) to temporarily support the formation of microscale geometries, which can be removed after a microstructure is constructed. In this study, an ultradense oil-in-organofluorine colloidal emulsion with photopolymerizable submicrometer droplets (diameter approximately 500 nm) was prepared and used as the required SA. Upon exposure to light, the colloidal emulsion undergoes a significant rheological change, which hardens the emulsion and presents the molding/protecting function that an SA must have. Importantly, the emulsion includes a synthesized fluorophilic/fluorophobic block copolymer surfactant to stabilize the droplet compartments, facilitating the dissolution of the postexposure SA. Two successfully built, complex, organic 3D microstructures show the effectiveness of using this novel SA material.