Interfacial energy of calcite-MHA/MUA self-assembled monolayers during nucleation

ABSTRACTThe interfacial energies between template-directed calcite nuclei and self-assembled monolayers of 16-mercaptohexadecanoic acid (MHA) and 11-mercaptoundecanoic acid (MUA) were measured. The results reveal that (1) the MHA and MUA significantly reduce the effective surface energy of calcite from about 97 mJ/m2 in solution to about 45.3 and 52.7 mJ/m2 on MHA and MUA respectively, providing a thermodynamic basis for the strong capacity of MHA and MUA to promote calcite nuclei; and (2) the barrier to nucleation is dominated by the free energy barrier which enhances the rate of surface nucleation on MHA and MUA.