Molecular Cohesion
Molecular Cohesion - Related Videos
01:07
Cohesion
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2019
Cohesion is the attraction between molecules of the same type, such as water molecules. Water molecules have an overall neutral charge but are polar molecule. An oxygen atom in one water molecule has a partial negative charge that can bind to a hydrogen atom with a partial positive charge in a second water molecule, forming a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules. Hydrogen bonds are responsible for water's cohesive nature. On a surface,...
12:49
Measurement of Aggregate Cohesion by Tissue Surface Tensiometry
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Cited by 10 •
2011
We describe a method of measuring binding energy, expressible as tissue surface tension, between cells within 3D tissue-like aggregates. Differences in tissue surface tension have been demonstrated to correlate with invasiveness of lung, muscle, and brain tumors, and are fundamental determinants of establishing spatial relationships between different cell types.
09:55
Molecular Cloning
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2023
Molecular cloning is a set of methods, which are used to insert recombinant DNA into a vector - a carrier of DNA molecules that will replicate recombinant DNA fragments in host organisms. The DNA fragment, which may be a gene, can be isolated from a prokaryotic or eukaryotic specimen. Following isolation of the fragment of interest, or insert, both the vector and insert must be cut with restriction enzymes and purified. The purified pieces are joined together though a technique called...
12:02
Molecular Evolution of the Tre Recombinase
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Cited by 4 •
2008
Here we report the generation of Tre recombinase through directed, molecular evolution. Tre recombinase recognizes a pre-defined target sequence within the LTR sequences of the HIV-1 provirus, resulting in the excision and eradication of the provirus from infected human cells. While still in its infancy, directed molecular evolution will allow the creation of custom enzymes that will serve as tools of molecular surgery and molecular medicine.
02:00
Molecular Models
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2020
Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models makes it easier to visualize the structures and shapes of atoms and molecules. Skeletal Model Simpler two-dimensional representations of chemical compounds are accomplished using skeletal models. The illustration shows only the molecular framework or bonds without explicitly showing the atoms. In this representation, many of the carbon atoms...
FAQs
Hydrogen bonding, electrostatic attraction, and van der Waals forces contribute collectively to molecular cohesion, rather than acting as isolated design variables. Their combined effect determines how much cohesive energy a material has and how strongly it resists separation. This helps engineers connect molecular-scale interactions with bulk strength, flow behavior, and durability.
Cohesive energy indicates how strongly molecules within a substance are held together. A material with stronger overall intermolecular attraction can show greater resistance to separation, while the same interactions may also affect deformation and flow. Engineers use this relationship to interpret material strength, durability, and processing behavior in polymers, fluids, coatings, and composites.
Molecular cohesion influences both surface tension and viscosity, but through different observable behaviors. At a surface, cohesive interactions contribute to the tendency of the material to maintain its boundary. Within a fluid, they affect resistance to flow. These properties help engineers evaluate wetting, spreading, lubrication, and manufacturing performance.
Material selection, chemical modification, and environmental conditions can all change how cohesion influences performance. Adjusting the substance itself may alter its intermolecular interactions, while surrounding conditions can affect the resulting behavior. Engineers consider these variables when seeking a balance among strength, flow, wetting, resistance to separation, and long-term durability.
Engineers evaluate cohesion when selecting materials whose internal integrity must support a particular use. For example, polymers, composites, coatings, lubricants, and fluids may require different balances of strength, flow behavior, wetting, and durability. Comparing these performance needs with the material's cohesive behavior supports more suitable choices for manufacturing and structural applications.
A practical approach begins by identifying the required outcome, such as improved strength, controlled flow, effective wetting, or greater durability. Engineers then select an appropriate material, consider chemical modification where needed, and account for environmental conditions. Examining the resulting cohesive energy and separation, surface, or flow behavior helps guide optimization for the intended application.