In this work, we examined the effect of length of alkyl chain attached to the benzene ring on the self-assembling phenomena for the series of phenol alcohol (PhA) derivatives, from...

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Herein, we investigated the molecular dynamics as well as intramolecular interactions in two primary monohydroxy alcohols (MA), 2-ethyl-1-hexanol (2EHOH) and n -butanol ( n BOH), by means of broad-band dielectric (BDS) and Fourier transform infrared (FTIR) spectroscopy. The modeling data obtained from dielectric studies within the Rubinstein approach [ Macromolecules 2013 46 7525 7541 ] originally developed to describe the dynamical properties of self-assembling macromolecules allowed us to calculate the energy barrier ( E a ) of dissociation from the temperature dependences of relaxation times of Debye and structural processes. We found E a ∼ 19.4 ± 0.8 and 5.3 ± 0.4 kJ/mol for the former and latter systems, respectively. On the other hand, FTIR data analyzed within the van’t Hoff relationship yielded the energy barriers for dissociation E a ∼ 20.3 ± 2.1 and 12.4 ± 1.6 kJ/mol for 2EHOH and n BOH, respectively. Hence, there was almost a perfect agreement between the values of E a estimated from dielectric and FTIR studies for the 2EHOH, while some notable discrepancy was noted for the second alcohol. A quite significant difference in the activation barrier of dissociation indicates that there are probably supramolecular clusters of varying geometry or a ring-chain-like equilibrium is strongly affected in both alcohols. Nevertheless, our analysis showed that the association/dissociation processes undergoing within nanoassociates are one of the main factors underlying the molecular origin of the Debye process, supporting the transient chain model.

In the present study, the behavior of the calcium channel blocker cilnidipine (CLN) infiltrated into silica (SiO 2 ) and anodic aluminum oxide (AAO) porous membranes characterized by a similar pore size (d = 8 nm and d = 10 nm, respectively) as well as the bulk sample has been investigated using differential scanning calorimetry, broadband dielectric spectroscopy (BDS), and Fourier-transform infrared spectroscopy (FTIR) techniques. The obtained data suggested the existence of two sets of CLN molecules in both confined systems (core and interfacial). They also revealed the lack of substantial differences in inter-and intramolecular dynamics of nanospatially restricted samples independently of the applied porous membranes. Moreover, the annealing experiments (isothermal time-dependent measurements) performed on the confined CLN clearly indicated that the whole equilibration process under confinement is governed by structural relaxation. It was also found that the β anneal parameters obtained from BDS and FTIR data upon equilibration of both confined samples are comparable (within 10%) to each other, while the equilibration constants are significantly different. This finding strongly emphasizes that there is a close connection between the inter-and intramolecular dynamics under nanospatial restriction.