Testing density scaling in nanopore-confinement for hydrogen-bonded liquid dipropylene glycol.

Recently, it has been demonstrated that the glassy dynamics of the molecular liquids and polymers confined at the nanoscale level might satisfy the density scaling law ( /) with the same value of the scaling exponent, , as that determined from the high-pressure studies of the bulk material. In this work, we have tested the validity of this interesting experimental finding for strongly hydrogen-bonded molecular liquid, dipropylene glycol (DPG), which is known to violate the / scaling rule in the supercooled liquid bulk state. The results of the independent dielectric relaxation studies carried out on increased pressure and in nanopores, have led to an important finding that when the density change induced by geometrical confinement is not very large, DPG can still obey the density scaling law with the same value of the scaling exponent as that found for the bulk sample.

Crystallization of supercooled fenofibrate studied at ambient and elevated pressures.

In this work, we have performed a detailed investigation on the crystallization tendency of the modeled glass-forming pharmaceutical compound, fenofibrate. To do this, we have employed four different experimental techniques allowing following of the crystallization process. This has included dielectric spectroscopy, optical microscopy, X-ray diffraction and differential scanning calorimetry.

Predicting Nanoscale Dynamics of a Glass-Forming Liquid from Its Macroscopic Bulk Behavior and Vice Versa.

The properties of a molecular liquid confined at the nanometer length scale can be very distinct from the bulk. For that reason, the macro- and the nanoscopic behaviors of glass-forming liquids are regarded as two nonconnected realms, governed by their own rules. Here, we show that the glassy dynamics in molecular liquids confined to nanometer pores might obey the density scaling relation, ρ/T, just like in bulk fluids.

Dielectric Relaxation Study at Ambient and Elevated Pressure of the Modeled Lipophilic Drug Fenofibrate.

We have investigated the molecular dynamics in supercooled liquid and glassy state of the pharmaceutical agent fenofibrate. To do that, dielectric relaxation studies at ambient and elevated pressure were performed. Data collected at atmospheric pressure were found to be in good agreement with that already reported in the literature.