“… 34 The polarity index ( / ) decreased from 0.13 for the original wood to 0.09 for the delignified wood, and further to 0.06 for the TEMPO-oxidized wood, indicating the reducing proportion of the polar components following the processes. 38 Figure 3 Surface energy evaluation of original wood, delignified wood, and TEMPO-oxidized wood See also Figure S1 . (A) Total surface energy.…”
“… 34 The polarity index ( / ) decreased from 0.13 for the original wood to 0.09 for the delignified wood, and further to 0.06 for the TEMPO-oxidized wood, indicating the reducing proportion of the polar components following the processes. 38 Figure 3 Surface energy evaluation of original wood, delignified wood, and TEMPO-oxidized wood See also Figure S1 . (A) Total surface energy.…”
“…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...…”
The thermal surface properties of graphenes and carbon materials are of crucial importance in the chemistry of materials, chemical engineering, and many industrial processes. Background: The determination of these surface properties is carried out using inverse gas chromatography at infinite dilution, which leads to the retention volume of organic solvents adsorbed on solid surfaces. This experimental and fundamental parameter actually reflects the surface thermodynamic interactions between injected probes and solid substrates. Methods: The London dispersion equation and the Hamieh thermal model are used to quantify the London dispersive and polar surface energy of graphenes and carbon fibers as well their Lewis acid-base constants by introducing the coupling amphoteric constant of materials. Results: The London dispersive and polar acid-base surface energies, the free energy of adsorption, the polar enthalpy and entropy, and the Lewis acid-base constants of graphenes and carbon materials are determined. Conclusions: It is shown that graphene exhibited the highest values of London dispersive surface energy, polar surface energy, and Lewis acid-base constants. The highest characteristics of graphene justify its great potentiality and uses in many industrial applications.
“…The IGC technique was used by Balard et al [23] to determine the surface properties of milled graphites, by Bogillo et al [24] to evaluate the surface-free energy components for heterogeneous solids, and by Das et al [25,26] to study the surface energy distributions of lactose and pharmaceutical powders. The adsorption of n-alkanes at zero surface coverage on cellulose paper and wood fibers [19,27] and solid surface polarity [28] using IGC at infinite dilution were studied. Feeley et al [29] studied the surface properties and flow characteristics of salbutamol sulphate, and the surface energy characteristics of micronized materials were determined [30].…”
Inverse gas chromatography at infinite dilution was used to determine the surface thermodynamic properties of silica particles and PMMA adsorbed on silica, and more particularly, to quantify the London dispersive energy γsd, the Lewis acid γs+, and base γs− polar surface energies of PMMA/silica composites as a function of the temperature and the recovery fraction θ of PMMA. The polar acid-base surface energy γsAB and the total surface energy of the different composites were then deduced as a function of the temperature. In this paper, the Hamieh thermal model was used to quantify the surface thermodynamic energy of polymethyl methacrylate (PMMA) adsorbed on silica particles at different recovery fractions. A comparison of the new results was carried out with those obtained by applying other molecular models of the surface areas of organic molecules adsorbed on the different solid substrates. An important deviation of these molecular models from the thermal model was proved. The determination of γsd, γs+, γs−, and γsAB of PMMA in both the bulk and adsorbed phases showed an important non-linearity variation of these surface parameters as a function of the temperature. The presence of maxima in the curves of γsd(T) highlighted the second-order transition temperatures in PMMA showing beta-relaxation, glass transition, and liquid–liquid temperatures. These three transition temperatures depended on the adsorption rate of PMMA on silica. The proposed method gave a new relation between the recovery fraction of PMMA and its London dispersive energy, showing an important effect of the temperature on the surface energy parameters of the adsorption of PMMA on silica. A universal equation relating γsd(T,θ) of the systems PMMA/silica to the recovery fraction and the temperature was proposed.
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