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[Display omitted] • A comprehensive study on self-aggregation of monohydroxy alcohols (MAs). • Impact of phenyl and cyclohexyl ring on the aggregation of MAs. • Aromaticity affects the self-assembling of MAs. • Phenyl ring introduces more heterogeneity in the organization of molecules than the cyclic one. In this paper, the steric hindrance effect related to the presence of either a cyclic or aromatic ring on the self-association process in the series of monohydroxy alcohols (MAs), from cyclohexanemethanol to 4-cyclohexyl-1-butanol and from benzyl alcohol to 4-phenyl-1-butanol, was studied using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, Broadband Dielectric Spectroscopy (BDS) and the Pendant Drop (PD) methods. Based on FTIR results, it was shown that phenyl alcohol (PhA) and cyclohexyl alcohol (CA) derivatives reveal substantial differences in the association degree, the activation energy of dissociation, and the homogeneity of supramolecular nanoassociates suggesting that the phenyl ring exerts a stronger steric impact on the self-assembling of molecules than cyclohexyl one. Additionally, XRD data revealed that phenyl moiety introduces more heterogeneity in the organization of molecules compared to the cyclic one. The changes in the self-association process of alcohols were also reflected in differences in the molecular dynamics of the H-bonded aggregates, as well as in the Kirkwood factor, defining the long-range correlation between dipoles, which were slightly higher for CAs with respect to those determined for PhAs. Unexpectedly it was also found that the surface layers of PhAs were more organized than those formed by CAs. Thus, these findings provided insight into the impact of aromaticity on the self–assembly process, H-bonding pattern, supramolecular structure, and intermolecular dynamics of the studied alcohols. [ABSTRACT FROM AUTHOR]

[Display omitted] • Local structure, interactions scheme, and molecular dynamics of butanol isomers. • Difference in dynamic and static properties between primary and secondary alcohols. • Presence of phenyl moiety does not affect the strength of H-bonds. • Linear associates occur in alcohols, irrespective of the presence of phenyl moiety. • Location of the hydroxyl group has a prominent effect on the H-bonding pattern. In this paper, we have studied local structure, interactions scheme and molecular dynamics of series of aliphatic butanol (AB) isomers: n-butanol, iso -butanol, sec -butanol, and their phenyl counterparts (PhB): 4-phenyl-1-butanol, 2-methyl-3-phenyl-1-propanol, and 4-phenyl-2-butanol by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR), and broadband dielectric spectroscopy (BDS) methods. XRD demonstrated that aside from the main peak related to the nearest-neighbour intermolecular correlations, there is a strong pre-peak at low scattering vector range for ABs, while for PhBs, this diffraction feature was weakly visible or not detected at all. At first sight, it suggests that molecules in aliphatic alcohols tend to associate and form medium-range order, while PhBs can be considered as disordered, simple liquids. However, further thorough FTIR and BDS spectroscopy investigations have shown that the phenyl moiety affects only slightly the degree of association and does not influence the strength of H-bonds in aromatic alcohols. What is more, PhBs are characterized by a similar Kirkwood factor (g k ≫ 1) to the ABs. 4-phenyl-2-butanol is characterized by the greatest g k ~ 3.7 among all studied herein alcohols, indicating a strong correlation between dipole moments and the formation of nanoassociates of chain-like topology in its structure. Combining results obtained from different experimental techniques, we pointed out that there are clear differences in dynamic and static properties between primary and secondary alcohols, including medium- and short-range order, variation in the strength of H-bonds and distribution of these types of interactions, the enthalpy of dissociation process, the glass transition temperature, and Kirkwood factor, irrespective of the presence of steric hindrance posed by the phenyl moiety. Results discussed in this paper clearly demonstrated that a superficial analysis of standard diffraction patterns, which are often the first step to probe the structure of materials, may lead to wrong conclusions. That is why complementary techniques must be applied together to understand the structure and behavior of assembling liquids. [ABSTRACT FROM AUTHOR]