“…In addition, 34 wt% silica colloidal suspension (Ludox TMA, Sigma‐Aldrich, St. Louis, MI), sodium chloride (NaCl, AR grade, Mallinckrodt, Paris, KY), and deionized water were mixed together with the nanorods to form the solutions to be freeze cast. The silica nanospheres in the Ludox suspension had a nominal diameter of 22 nm (manufacturer reported), a density of 2.37 g/cm 3 , and were well dispersed in deionized water.…”