Control of Crystalline Forms and Morphologies for CaCO_3 Crystals on 3-Mercaptopropionic Acid Self-assembled Monolayers

In the present study,the crystals of CaCO3 were obtained by the slow diffusion of NH3 and CO2 into the CaCl2 solutions.Experimental results showed that both 3-mercaptopropionic acid self-assembled monolayers(SAMs) and solution temperature have significant influence on the crystalline forms and morphologies of calcium carbonates crystals.The precipitations of calcium carbonate were easily obtained from solutions at 25 ℃ but with polymorphism including calcite,vaterite and aragonite,while on the self-assembled monolayers there exist calcite crystals only.The morphologies of calcite crystals can be mediated by temperature.For example,the calcite precipitated at 25 ℃ has smooth surface while that precipitated at 60 ℃ has porous structure even though they were obtained on the same SAMs.XRD analysis showed that the growth of calcite on SAMs were along(104) and(006) planes.