A Low-Cost, Non-hazardous Protocol for Surface Texturing of Glass Particles

We present a cheap, efficient, and non-hazardous protocol for altering the roughness of hard particles at the nanometer-scale using a stone tumbler, a tool which is normally used for polishing stones. Six different textures were achieved by lining the tumbler with sandpaper of mean grit diameters $$d_{\mathrm{g}}=201$$dg=201, 58.5, 18.3, 12.6, and $$8.4\,\upmu \hbox {m}$$8.4μm. Two textures were created by tumbling a batch of glass spheres for 4 h and for 12 h with the $$12.6\,\upmu \hbox {m}$$12.6μm sandpaper; all other textures were established by tumbling for 12 h. Surface roughness was characterized by the integral length scale, $$\xi$$ξ, evaluated from 7 nm/pix resolution scanning electron microscope images. Roughness size increased from $$\xi = 24$$ξ=24 to 31 nm as the grit size decreased from $$d_{\mathrm{g}} = 201$$dg=201 to $$18.3\,\upmu \hbox {m}$$18.3μm, and then decreased to $$\xi = 6.4\,\hbox {nm}$$ξ=6.4nm at the smallest $$d_{\mathrm{g}}$$dg. The largest $$\xi \,(= 34\,\hbox {nm})$$ξ(=34nm) was achieved using a $$12.6\,\upmu \hbox {m}$$12.6μm sandpaper and the shorter tumbling time of 4 h. The permeability of a packed column of the particles broadly decreased with increasing $$\xi$$ξ, indicating that permeability decreases with increasing roughness size.