Avoiding “mud” cracks during drying of thin films from aqueous colloidal suspensions

The critical cracking thickness hc of dried films is improved by controlling the aqueous alumina suspension formulation. On the left is a 430-μm thick cracked film of pH 9 suspension where h≈3hc. On the right is a 1265-μm thick cracked film of pH 1.75 suspension where h≈3hc.