High Pressure Behavior of the Hybrid Material AlPO4-5+Azobenzene: An In-situ Synchrotron X-ray Diffraction Study

In this paper we present the results of a study aimed at the understanding of the high-pressure behavior of a hybrid composite constituted by azobenzene molecules embedded in 1-D nano-channels of AlPO4-5 porous material. In-situ synchrotron high pressure X-ray powder diffraction experiments have been performed on the hybrid material and the starting porous material AlPO4-5. The “non-penetrating” silicone oil and the “penetrating” methanol:ethanol:water 16:3:1 mixture (m.e.w.) have been used as pressure transmitting media. Using silicone oil, the presence of dye molecules within the zeolite channels affect the pressure behavior of the material increasing its compressibility. In the m.e.w. experiment, the penetration of molecules in the channels influences the elastic behavior of the material, leading to a less compressible material. The reversibility of the unit cell parameters after the pressure treatment and the strong stability showed by the hybrid material suggest the possibility to extend the range of applicability of these composites.