Structural stability of a colloidal solution of Ca(OH)2 nanocrystals exposed to high relative humidity conditions

The effect of high relative humidity (90% and 75% RH) on phase transformation and stability of CaCO3 polymorphs has been studied based on the structural and morphological changes from a colloidal solution based on Ca(OH)2 nanocrystals. Carbonation process has been confirmed indicating differences in nucleation and stability of CaCO3 polymorphs as a function of RH. Local fluctuations in the water/alcohol ratio significantly affect the precipitation/dissolution of anhydrous and hydrated polymorphs that are reflected in the particle size. Changes in lattice parameters and particle size are related to surface tension fluctuations, release of residual water and time of exposure. These results highly contribute to evaluate the stability of the Ca(OH)2 nanoparticles in high humidity conditions.This work was supported by the Government of the Community of Madrid (Spain), the GEOMATERIALES (S2009/MAT-1629/GEOMATERIALES) and CONSOLIDER-TCP (CSD2007-0058) programmes and by the JAE-Doc CSIC contracts.Peer Reviewe