Production of sub-10 micrometre cellulose microbeads using isoporous membranes

The production of sub-10 µm cellulose microbeads via membrane emulsification using isoporous membranes is reported here for the first time. Poly(ethylene terephthalate) membranes, with defined interpore distances, pore diameters and straight-through pores were fabricated via photolithography. A dispersed phase of 8 wt% cellulose solution was extruded through the membrane pores, forming, due to shear provided by an overhead stirrer, cellulose solution droplets dispersed in a continuous phase composed of 2 wt% and 5 wt% Span in sunflower oil. Upon phase inversion with ethanol, sub-10 µm microbeads with a coefficient of variation (CV) < 45 % were produced by exploring the Weber number (We_d) - Capillary number (Ca_c) emulsion generation space. These results show that sub-10 µm cellulose microbeads can be produced using isoporous polymer membranes fabricated via photolithography, for use in a wide range of applications in the personal care, food and drug industries.