Heating and sorption effects on silicalite-1 unit cell size and geometry

The temperature response of the silicalite-1 unit cell is investigated via X-ray diffraction experiments and lattice dynamics simulations, with the use of a newly proposed force-field. The numerical results are in very good agreement with present and literature data. Further analysis of the present data shows that the Rigid Unit Mode (RUM) mechanism that is proposed in the literature is the dominant mechanism of thermal contraction of the zeolite. In addition, the expansion of the silicalite-1 unit cell upon n-hexane sorption is investigated. Simulation results show that even though the discernible changes of the crystal dimensions upon heating or sorption may affect membrane-substrate mechanical interactions, they have a minimal effect on the overall sorption capacity.

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► Study of silicalite-1 unit cell volume and structure upon heating and n-hexane sorption.
► Theoretical calculations based on our newly developed force-field predict satisfactory unit cell contraction upon heating.
► Simulation results analysis shows that rotations of rigid tetrahedra are responsible for contraction.
► Our experimental results show that the unit cell expands monotonically upon n-hexane sorption.
► Sorption induced volume and structural changes do not affect sorption capacity.