Cuticular energy

Several attempts on theoretical prediction of yt are found in the literature according to some models, yx is more closely related to the cuticular energy defined in Chapter V than to the true surface energy, but cuticular energy implies no contractile tendency and cannot pull along the line KO of Fig. 12. 

The surface layers of solids usually differ from the deeper zones of the same specimen in their chemical composition, their degree of lattice perfection (e.g., the frequency of dislocations), their state of stress, and so on. This renders unpalatable the notion of a surface tension in solids, but suggests the existence of a kind of surface energy, unknown in liquids, which it was proposed to designate as cuticular energy. 

The above example suffices to formulate the 3 main differences between the true surface energy (as in liquids) and the cuticular energy. 

Usually, however, the other sources of cuticular energy (C.E.), referred to at the start of this section, also must be taken into account. 

Solids possess an energy unknown in typical liquids. This cuticular energy exists because the surface region of innumerable solids has a chemical composition, a frequency of lattice defects, and so on, different from those in the bulk. 

Small solid particles obtained by cooling of vapors, by grinding, or many other methods, usually have a less perfect lattice and more impurity than have bigger crystals of nominally identical composition. Hence, the cuticular energy of the former exceeds that of the latter. 

Cuticular energy implies no tendency of the surface to contract, i.e., no surface tension. The theoretical calculations of the difference in energy between a broken and an unbroken crystal, if correct, afford a quantity which is related to cuticular energy and, like this, causes no contractile tendency. 

The work of rupture is not transformed into heat quantitatively because the strata next to the rupture surfaces, as a rule, are in a more disordered state than the bulk of the two solid fragments see the above section on Rupture ork and Plastic Deformation. The energy residing in the disturbed surface layers received the name "cuticular". Thus, fracture work = heat + cuticular energy [2]. 

Yoder, J.A., Benoit, J.B., Rellinger, E.J. and Ark, J.T. (2005b). Critical transition temperature and activation energy with implications for arthropod cuticular permeability. J. Insect Physiol., 51, 1063-1065. 

Platts and Abraham (2000) used their LSER or linear free energy relationship (LFER) descriptors to model plant cuticular matrix-water partitioning (Kmxw) ... 

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