Effect of the degree of substitution on the hydrophobicity of acetylated cellulose for production of liquid marbles

Acetylated cellulose powders with varying degree of substitution (DS) were prepared by reacting cellulose with acetic anhydride. The effect of DS on the hydrophobic properties of acetylated cellulose was examined based on contact angle and mechanical stability measurements. The surface energy of the acetylated cellulose decreases with increasing DS, and for DS of 0.39, the acetylated cellulose was able to encapsulate a water droplet to form a liquid marble. The corresponding cellulose acetate powder-over-water spreading coefficient was ca. 8.9. Increasing DS also improved the mechanical stability of the liquid marble. This study opens important perspectives for the precise control of DS of cellulose acetate for various practical applications in membranes, filters, scaffolds, and textiles.