Temperature Dependence of the Polar and Lewis Acid–Base Properties of Poly Methyl Methacrylate Adsorbed on Silica via Inverse Gas Chromatography

Abstract

The adsorption of polymers on solid surfaces is common in many industrial applications, such as coatings, paints, catalysis, colloids, and adhesion processes. The properties of absorbed polymers commonly vary with temperature. In this paper, inverse gas chromatography at infinite dilution was used to determine the physicochemical characterization of PMMA adsorbed on silica. A new method based on the London dispersion equation was applied with a new parameter associating the deformation polarizability with the harmonic mean of the ionization energies of the solvent. More accurate values of the dispersive and polar interaction energies of the various organic solvents adsorbed on PMMA in bulk phase and PMMA/silica at different recovery fractions were obtained, as well as the Lewis acid–base parameters and the transition temperatures of the different composites. It was found that the temperature and the recovery fraction have important effects on the various physicochemical and thermodynamic properties. The variations in all the interaction parameters showed the presence of three transition temperatures for the different PMMA composites adsorbed on silica with various coverage rates, with a shift in these temperatures for a recovery fraction of 31%. An important variation in the polar enthalpy and entropy of adsorption, the Lewis acid–base parameters and the intermolecular separation distance was highlighted as a function of the temperature and the recovery fraction of PMMA on silica.

Thermal Surface Properties, London Dispersive and Polar Surface Energy of Graphene and Carbon Materials Using Inverse Gas Chromatography at Infinite Dilution

“…Nevertheless, the negative values of the acid-base constants indicates that the empirical relation used to calculate these constants should be corrected. In a previous paper [ 59 ], a new relation was proposed which takes into account the amphoteric effect by adding a new coupling acid-base constant which corrects this gap: . The resolution of such a linear system was developed in several previous works [ 26 , 58 , 72 ].…”

“…The standard deviation of the obtained retention time t R was less than 1% in all measurements. The temperatures of the injector and detector were fixed at 200 • C. Infinite dilution of the probes was satisfied by using 1 µL Hamilton syringes and injecting extremely small quantities of the vapor probe, satisfying the limit of detection of the FID of high sensitivity (Figure S2) to practically realize the zero-surface coverage [59,72]. The columns containing the solid particles were preconditioned at 130 • C overnight to ensure the total desorption of water molecules or any other residual impurities [59,72].…”

“…The lack of information and the different gaps encountered in this research area guided the objective of our study for accurate determination of the surface properties of graphene and carbon materials, which are required to obtain real guidance for the design and manufacturing of graphene-based biomaterials, medical instruments, structural composites, electronics, and renewable energy devices [ 20 ]. The present work is thus devoted to determination of the thermal surface properties, the London dispersive and polar acid-base surface energies, and the Lewis acid-base parameters of graphene and carbon materials as a function of the temperature by using the IGC technique [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ] at infinite dilution and applyi...…”

Thermal Surface Properties, London Dispersive and Polar Sur-face Energy of Graphene and Carbon Materials by Inverse Gas Chromatography at Infinite Dilution

“…The temperatures of the injector and detector were fixed at 200 °C. The infinite dilution of the probes was satisfied by using 1 μL Hamilton syringes and injecting very small quantities of the vapor probe, satisfying the limit of detection of the FID of high sensitivity, to practically realize the zero-surface coverage [60,75]. The columns containing the solid particles were preconditioned at 130 °C overnight to insure the total desorption of water molecules or any other residual impurities [60,75].…”

The Effect of Temperature on the London Dispersive and Lewis Acid-Base Surface Energies of Polymethyl Methacrylate Adsorbed on Silica by Inverse Gas Chromatography

“…However, classic chromatographic methods were used to determine the dispersive and polar-free energies of adsorbed organic molecules on the solid surfaces. In a recent study [55], the previous results were corrected using the new methodology based on the London dispersion interaction, and the new Lewis acid-base properties of PMMA/silica were obtained. The various dispersive, polar, and Lewis acid-base surface energies of the composites were not studied in the literature in light of the new thermal model.…”