Cohesive energies from monolayer

Cohesive Energies from Monolayer Desorption Studies... 

Measurement of the free energies of monolayer desorption from the rates of desorption depends on whether equilibrium exists between the monolayer and a thin region of solution immediately beneath the film. The relation which tests this condition (Equation 8) must correctly predict the dependence of the rate constant for desorption, k8, on 7r. For the sulfate, phosphonate, and carboxyl films in this study Equation 8 is obeyed within the range of experimental error (2 to 5%). Therefore, it is reasonable to assume that the necessary equilibrium condition does exist. The cohesive forces in the monolayer follow directly from the evaluation of the free energies of desorption. 

Implicit in the determination of Wr, the cohesive energy in the hydrocarbon region of the long-chain monolayer, is the assumption that W0, the free energy of desorption for one —CH2— group, obtained with relatively short hydrocarbon chains, is independent of the length of the hydrocarbon moiety. The validity of this assumption can be checked for sulfate films where W(. may be obtained from desorption studies as... 

Furthermore, the activation energy for chemical reaction is also proportional to the atomic cohesive energy. Therefore, the chemical stability of the undercoordinated atoms is lower than that of the atoms in the bulk, which may explain why the CNT could burn using an ordinary camera flash under the ambient conditions. Conclusion on the CN dependence of C-C bonding identities applies to GNR as well as the curvature effect is weak. Comparing the derivative from the SWCNT to the measured modulus of 1.0 TPa under the assumption of 0.335 nm thick of the monolayer graphene [33], the elastic modulus of the graphene is 1.0 x 0.335/0.142 = 2.36 TPa, which is substantially the same to that of the SWCNT (2.56 TPa) [45]. 

The slippery or low-friction of ice results from the lone pair weak yet elastic interaction and the high density of surface charge instead of the liquid lubrication. Because of the cohesive energy gain of the two intramolecular H-O bonds, a monolayer of water performs solid like with high elasticity and charge density as the increase of raises the T. This expectation coincides with higher surface... 

Figure 13.9 Illustrations of the cohesive coating mechanism and details of the coating flows, (a) Adhesive (Fj and cohesive (Fj force diagram between hydrophobic and hydrophilic surfaces. Contact angles depend on the relative forces between solvent molecules and surfaces. In the case of downward concavity, the cohesive force is higher than the adhesive force, whereas upward concavity means that the adhesive force is higher than the cohesive force, (b) The adhesive force dominant condition. Adhesive forces are enhanced by surface energy modifications, such as O2 plasma treatment. Therefore, the flow rate is reduced by adhesive forces, (c) Cohesive force dominant condition. Adhesive forces are relatively reduced by self-assembled monolayers (SAMs). Thus, the flow rate is increased. Reproduced from ref. 23 with the permission of Wiley-VCH Verlag GmbH Co. KGaA, 2014.

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