How thick is a silk fiber in micrometres?

Question

How thick is a silk fiber in micrometres?

Answer 1

About 10 microns. This was hard to find! A silk fiber is about 2 deniers (ref. 1). A denier, it turns out, is a measure of linear density or mass/length (1 g per 9 km, or ~10^-6 g/cm; ref. 2). According to ref. 3, silk's specific gravity is ~1.4, so a 2-denier silk fiber should have a cross-sectional area of ~1.5*10^-6 cm^2 and thus be ~1.3*10^-3 cm or 13 microns thick. Ref. 3 roughly confirms this in its diagram of a silk fiber (figure 3); their number is 10 microns. (If I had found this picture first, I could have saved some work!)