Dependence of the order and crack density of polystyrene opals on volume fraction, humidity and temperature

We have fabricated polystyrene opals by vertical deposition with colloidal spheres of 419 nm in diameter. Different parameters such as the concentration, temperature and relative humidity have been systematically varied in order to study the dependence of the crystalline quality of the opals on these parameters. The opals have been optically and structurally characterized, paying particular attention to the size and distribution of the domains for each fabrication condition. We have noticed a dependence of the size of the domains on the thickness which corroborates a previous study. From these results we can conclude that the characterization of the homogeneity of the thickness of the opals can be done just by using microscopy. We also report a dependence of the order of the opals on relative humidity and a selective adhesion of the opals to the substrate depending on concentration and surface chemistry. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)