Biomimetic microspheres with rough structure by the geometric potential theory

Abstract

Rough structure microspheres developed using electrospinning show many superior properties, such as increased specific surface area and enhanced wettability, yielding numerous benefits to the applications in adsorption, separation, and others. In this study, biomimetic rough microspheres on string of polymethyl methacrylate nanofiber with hierarchical structure of micron-scale microsphere, and nanoscale Y-shape edges on the microsphere were innovatively and success-fully developed by electrospinning. The resulting microsphere exhibited a steering-wheel-like Y shape, and the formation process was physically explained by the geometric potential theory. In the spinning process, irregular hexahedron-like droplet was firstly formed. Then, the hexahedron-like droplet changed to tetrahedron-like after the bottom contacted the collector. The tetrahedron-like droplet evolved into Y-shaped microsphere due to the geometric potential and the collapse of the center part owing to the solvent evaporation. Furthermore, similar to the natural lotus leaf, the hierarchical steering-wheel structure strengthened the nanofiber membrane roughness and endowed the membrane with superhydro-phobicity, indicating the potential application in water treatment (oil-water separation, and dye and heavy metal ion adsorption), functional surface materials (self-cleaning fabrics), energy generation and other salient areas.