Rise and side infiltration in opals and porous materials for their skin-free replica synthesis

A floating opal placed on a certain liquid will cause the liquid to climb through the opal gaps, fill all its pores, and stop almost of its upper surface without covering it. A drop of solution with a surface tension much lower than that of water, deposited on a hydrophilic substrate near an opal, rapidly spread over a large surface forming a film which will surround the opal and infiltrate it from the side without covering it. High quality, skin-free, inverse opals can be synthesized by rise and side infiltration of solution in opals. The overlayer absence leads to the fabrication of mechanically robust, crack-free, completely filled photonic crystals which preserve the long rage order of initial opals. Inverse opals of sodium silicate were synthesized starting from polystyrene nanospheres self-assembled through hanging drop technique followed by their rise and side infiltration, casting, and template removal. Crystalline material inverse opals such as glycine, sodium chloride, and sulfur were also synthesized.