Deposition of β-Polyfluorene by Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation

Emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) was used to deposit thin films of polyfluorene (PFO) with semi-crystalline phase domains (β-PFO), which has been performed, previously, only by solution phase processing. Various target emulsion recipes were studied, with emphasis on the primary solvent choice, emulsion mixing time, secondary solvent concentration, or total water concentration. The emulsified particle size for each recipe was compared using dynamic light scattering. Additionally, elevated growth temperature of the substrate was considered for controlling film formation. The surface quality of films was determined by atomic force microscopy, and β-PFO concentration was monitored using photoluminescence or UV–visible absorbance spectroscopy. Importantly, in contrast to solution-based deposition of β-PFO in thin films, emulsion-based RIR-MAPLE demonstrated the ability to increase β-PFO content without degrading, simultaneously, the surface properties of the films. This initial result helps establish the ability of RIR-MAPLE to control and promote semi-crystalline phases in polymer films.