Free Surface Energy and Hansen Solubility Parameter Vector Field. Interface Thickness
Metadatos
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MDPI
Materia
Hansen solubility parameters free surface energy surface tension
Fecha
2024-07-03Referencia bibliográfica
Bailón-Moreno, R.; Bailón-Ruiz, M.Á.; Aljadiri, A.S.A. Interface Thickness. Appl. Sci. 2024, 14, 5834. [https://doi.org/10.3390/app14135834]
Patrocinador
Doctoral Program in Chemistry of the University of Granada (codes ISCED 1 Chemistry and ISCED 2 Physical, Chemical, Geological Sciences). Escuela Internacional de Postgrado of Universidad de Granada.Resumen
In this paper, a three-dimensional vector field model is proposed, whose dimensions are
the Hansen Solubility Parameters: dispersion parameter (δD), polarity parameter (δP), and hydrogen
bonding parameter (δH). The vector space that defines the field has the peculiarity of having a
dispersion vector with a magnitude of 2 as its base vector, while the polarity and hydrogen bonding
vectors have a magnitude of 1. A substance is characterised as a position vector, and the interaction
between two substances is determined by calculating the vector difference of both, known as the
interaction vector. The interaction among substances may involve solubility, swelling, cracking,
surface tension, interface tension, and any physical phenomena where the intermolecular energies
of dispersion, polarity or hydrogen bonding come into play. This paper studies free surface energy
(surface and interfacial tension). It has been found that free surface energy is directly proportional to
the square of the magnitude of the interaction vector. The proportionality constant, τ, is expressed in
length units, has a value of 0.025 nm, and does not depend on the chemical nature of the substance
or state of matter (solid, liquid or gas). The constant value τ appears universal and aligns with the
thickness of interfaces, thereby supporting Guggenheim’s hypothesis. This hypothesis asserts that
interfaces possess actual thickness and are not merely mathematical surfaces, as originally postulated
by Gibbs. Moreover, it also has been found that the interface thickness, τ, is approximately equal to
half of the Bohr radius, a0, which is defined by universal constants. Because the solubility parameters
of thousands of substances are known and can be easily determined from their molecular structure,
a good approximation of the surface and interfacial tension of any given substance can now be
calculated. It has also been found that the contact angles of sessile droplets in three-phased systems
can be calculated from the interaction vectors of the implicated substances.