Diameter (nm) Number distribution (%) 33.9 1.79 34.8 3.03 35.4 4.00 35.9 4.82 36.3 5.51 36.7 6.00 37.1 6.41 37.4 6.68 37.8 6.82 38.1 6.89 38.5 6.82 38.8 6.68 39.2 6.41 39.6 6.00 40.0 5.51 40.5 4.82 41.0 4.00 41.7 3.03 42.8 1.79