Thekey differencebetween adhesion and cohesion is that附着力之间的吸引力是物质或molecules that are not similar whereas cohesion is the attraction between the molecules or substances that are similar.
有各种各样的现象可以解释我们在日常生活中观察到的事物。尽管有时我们不专注于这些小细节,但它们是有助于保持地球生命的人。粘附和凝聚力是两个这样的现象。尽管听起来相似,但它们的术语是完全不同的。
CONTENTS
1.Overview and Key Difference
2.What is Adhesion
3.What is Cohesion
4.Side by Side Comparison – Adhesion vs Cohesion in Tabular Form
5.概括
What is Adhesion?
Adhesion is the attractive force between two types of molecules, which are different from each other. For example, the attraction between the water molecules with the walls ofxylem vesselsis adhesion. Because of this force, water can travel through the xylem in plants. Moreover, these areintermolecular forces.
There are five mechanisms to explain the mechanism of adhesion as followings:
- Mechanical adhesion
- Chemical adhesion
- Dispersive adhesion
- 静电粘附
- Diffusive adhesion
In mechanical adhesion, adhesive material holds the surface by filling into the holes or pores in it. In chemical adhesion, chemical bonds form, and they can be either ionic or covalent bond. If the bonds are ionic, then electrons may donate or attract, or else electron sharing may present in covalent bonding.
除此之外,分子间键(如氢键)可以参与将两种材料固定在一起。如果两种材料由于Van der Waals forces, then we can explain that mechanism by dispersive adhesion.
Moreover, when there is a slight (permanent or temporal) charge separation in a molecule, we say the molecule has become polarized. The opposite charges tend to attract each other; hence, there are attractive forces between the molecules. An electron passing in conductive material may cause electrical charge differences. The charge differences can cause attractive electrostatic forces between materials. We call it electrostatic adhesion.
当两种类型的分子相互溶于彼此时,它们可以移入另一个表面。因此,它导致扩散粘附。粘附力的强度取决于机制。至于如何发生。例如,如果接触表面积非常大,则范德华力的强度更高。因此,色散粘附力的强度更高。
What is Cohesion?
凝聚力是两个相似分子之间的分子间力。例如,水分子之间具有分子间吸引力。水的这种特性使水分子能够保持一致。我们可以解释雨滴的形状或水滴的存在,而不是通过内聚力来解释单个分子。
此外,水分子的氢键能力是水分子凝聚力背后的主要原因。每个水分子可以与其他水分子形成四个氢键。因此,吸引力的收集要强得多。相似分子之间的静电力和范德华力也会引起粘附。但是,由于范德华力引起的粘附力较弱。
粘附和凝聚力有什么区别?
Adhesion is the attractive force between two types of molecules, which are different from each other and cohesion is the intermolecular force between two similar molecules. Therefore, the key difference between adhesion and cohesion is that the adhesion is the attraction between substances or molecules which are not similar whereas cohesion is the attraction between the molecules or substances that are similar.
Moreover, another significant difference between adhesion and cohesion is that the adhesion includes electrostatic attractions while cohesion includes Van Der Waal forces and hydrogen bonding. For instance, cohesion is between two water molecules and adhesion is between water molecules and the walls of xylem vessels.
概括– Adhesion vs Cohesion
Adhesion and cohesion are two types of intramolecular forces. The key difference between adhesion and cohesion is that adhesion is the attraction between substances molecules which are not similar whereas cohesion is the attraction between the molecules or substances that are similar.
Reference:
1. Libretexts. “Cohesive and Adhesive Forces.” Chemistry LibreTexts, National Science Foundation, 26 Nov. 2018.Available here
Image Courtesy:
1.”9897320755″ byZappys Technology Solutions(CC由2.0)viaFlickr
2.”Drops I”By Staffan Enbom from Finland(CC由2.0)viaCommons Wikimedia
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