Controlled fabrication of polyfluoroimide microspheres by electrospray technique

Bowl-like polymer microspheres (BPMs) of polyfluoroimide (PIF) with a single cave and interior porosity are successfully prepared in this work by using one-step electrospray (ES) technique. The effects of polymer solution and process control parameters on the surface appearance and sizes of resulting microspheres are investigated. The experimental results indicate that the cyclopentanone (CPT) is used as the solvent, polymer microspheres with porous structure, tailed and elongated, single-cave and beaded fibers can be prepared respectively. Compared to the cyclopentanone, the N, N-dimethylacetamide (DMAC) solvent contributes to the formation of microspheres with spherical and rough surface structure. The diameters of BPMs and single-cave can be regulated by varying the PIF solution concentration, applied voltage and flow rate during the electrospray process. The diameter ranges for the obtained PIF microspheres are 2.75-5.03 μm with single-cave at 1.11-2.72 μm respectively. The sizes of both the single-cave and microspheres tend to reduce with the decrease of flow rate or increase of applied voltage. These BPMs with interior porosity have a broad application prospect in microreactor, catalyst supports, drug carrier and captures for cells due to its large effective surface area and strong absorption capacity.