Dear Mahvash Yarahmadi, cohesive energy density is an estimate for all sorts of intermolecular forces inovolved in chains' interactions. It is a mean value regardless the interchains order. Enthalpy in the other side is specific to regular or ordered domains such as crystalline zones. My Regards
Yes, but if you are not a polymer scientist it will be a bit difficult to read the following books:
- J. M. C. Cowie, Polymers: Chemistry and Physics of Modern Materials
- Intermolecular and surface forces, Jacob Israelachvili
Hello,
In structure stability calculations, cohesive energy is often used instead of enthalpy because it directly relates to the strength of the bonds that hold a material together.
For crystalline solids, metals, ceramics, and even polymers, cohesive energy gives insight into the stability by quantifying the energy needed to overcome all interactions holding the structure together.
Unlike enthalpy, which can vary with temperature and pressure, cohesive energy is a fixed property at a given structure. This makes it easier to compare different materials or polymorphs under standard conditions.
Adhesion energy, on the other hand, is particularly useful in contexts like polymers and oligomers where interfacial interactions play a critical role in the material's performance.
Mahvash Yarahmadi
Selase A. K. Kpo
I am adding to the answers of previous consultants, because the difference between cohesion and enthalpy is not given in full.
Cohesion is the amount of energy that must be spent to break intermolecular bonds in a polymer. Usually this energy is used for the mechanical characteristics of the polymer.
Enthalpy (or enthalpy change) is a parameter of the process of chemical thermodynamics, when the process occurs spontaneously, for example, in a chemical reaction of a polymer, hydration of a polymer. The polymer does not break spontaneously. However, in a chemical reaction, bonds can break spontaneously and other bonds can form.
cohesive energy is used in structure stability calculations because it directly measures the strength of interactions within a solid, providing a clear and direct assessment of stability. Enthalpy, while important for thermodynamic processes, includes additional factors that might complicate or obscure the intrinsic bond strength in a material.
Abstract
📷
The cohesive or atomization energy of an ionic solid is the energy required to decompose the solid into its constituent independent gaseous atoms at 0 K, while its lattice energy, Upot, is the energy required to decompose the solid into its constituent independent gaseous ions at 0 K. These energies may be converted into enthalpies at a given temperature by the addition of the small energies corresponding to integration of the heat capacity of each of the constituents. While cohesive energies/enthalpies are readily calculated by thermodynamic summing of the formation energies/enthalpies of the constituents, they are also currently intensively studied by computational procedures for the resulting insight on the interactions within the solid. In supporting confirmation of their computational results, authors generally quote “experimental” cohesive energies which are, in fact, simply the thermodynamic sums. However, these “experimental” cohesive energies are quoted in many different units, atom-based or calorimetric, and on different bases such as per atom, per formula unit, per oxide ion, and so forth. This makes comparisons among materials very awkward. Additionally, some of the quoted values are, in fact, lattice energies which are distinctly different from cohesive energies. We list large numbers of reported cohesive energies for binary halides, chalcogenides, pnictogenides, and Laves phase compounds which we bring to the same basis, and identify a number as incorrectly reported lattice energies. We also propose that cohesive energies of higher-order ionic solids may also be estimated as thermodynamic enthalpy sums.
- Badges
- Science topic
- Similar topics
- Chemistry