On the possibility of obtaining crystalline materials containing extended cylindrical pores

Using the example of studying the behavior of heated crystals of copper sulfate CuSO₄ · 5H₂O that are derived from an aqueous solution and contain three-dimensional inclusions of the mother environment, we show that the heating of these crystals in an inactive medium leads to the discharging of inclusions due to the emersion of their content on the surface. The routes for discharging mother-solution inclusions are determined using optical and electron microscopy and X-ray topography. According to the proposed model, the inclusions are discharged because they expand on being heated and press the crystal matrix. As a result, the solubility of copper sulfate in the mother environment increases, and, along the linear dislocation that passes close to the inclusions and emerges on the crystal surface, a cylindrical pore appears via which the mother solution goes from the bulk of the crystal to its surface. Finally, we obtain a porous material that can reversibly absorb appreciable amounts of an inert fluid (e.g., alcohol) from the ambient environment.