Adhesion

Definition

Adhesion is the attractive force that exists between the surfaces of two different materials, causing them to cling or stick together. This intermolecular force is crucial in various chemical and physical processes, particularly in the context of 10.1 Intermolecular Forces.

5 Must Know Facts For Your Next Test

1. Adhesion is responsible for the ability of water to climb up a narrow tube against the force of gravity, a phenomenon known as capillary action.
2. The strength of adhesive forces depends on the polarity of the molecules involved, with polar molecules exhibiting stronger adhesion than non-polar molecules.
3. Adhesion plays a crucial role in the formation of thin films, coatings, and the ability of certain materials to stick to surfaces.
4. Adhesion is essential in the functioning of many biological systems, such as the ability of geckos to climb vertical surfaces and the way that water is transported through plant tissues.
5. Understanding adhesion is important in the design of various materials and devices, such as glues, paints, and microfluidic systems.

Review Questions

• Explain how adhesion relates to the concept of intermolecular forces and its importance in chemical and physical processes.
  • Adhesion is a type of intermolecular force, which refers to the attractive forces that exist between the surfaces of different materials. These forces are responsible for the ability of materials to stick or cling to one another, and they are crucial in a wide range of chemical and physical processes. For example, adhesion is essential in the formation of thin films, coatings, and the ability of certain materials to adhere to surfaces. It also plays a key role in biological systems, such as the way that water is transported through plant tissues and the ability of geckos to climb vertical surfaces. Understanding adhesion and its relationship to intermolecular forces is important in the design and development of various materials and devices.
• Describe how the polarity of molecules affects the strength of adhesive forces and provide examples of how this principle is applied in real-world scenarios.
  • The strength of adhesive forces is directly related to the polarity of the molecules involved. Polar molecules, which have an uneven distribution of electrons and a resulting partial positive and negative charge, exhibit stronger adhesive forces than non-polar molecules. This is because the partial charges on the polar molecules can interact with the partial charges on the surface of another material, creating a stronger attractive force. For example, the ability of water to climb up narrow tubes against the force of gravity, known as capillary action, is due to the strong adhesive forces between the water molecules and the surface of the tube. Similarly, the adhesive properties of certain glues and paints are influenced by the polarity of the molecules in their formulations, allowing them to effectively stick to a variety of surfaces.
• Analyze the role of adhesion in the functioning of biological systems and explain how this understanding can be applied to the design and development of materials and devices.
  • Adhesion plays a crucial role in the functioning of many biological systems. For instance, the ability of geckos to climb vertical surfaces is due to the adhesive forces between the microscopic hairs on their feet and the surface they are climbing. Similarly, the transport of water through plant tissues is facilitated by the adhesive forces between the water molecules and the cell walls. Understanding the principles of adhesion and how it operates in these biological systems can inform the design and development of various materials and devices. For example, the study of gecko feet has led to the creation of synthetic adhesives that can mimic their remarkable sticking power, with potential applications in fields like robotics, construction, and medicine. Additionally, the understanding of capillary action and adhesion has been applied in the design of microfluidic devices, which rely on the precise control and manipulation of small amounts of fluids. By leveraging the principles of adhesion, engineers and scientists can create innovative solutions to a wide range of practical problems.

Related terms

Cohesion:

The attractive force that exists between like molecules, holding them together within the same substance.

Surface Tension:

The attractive force between the molecules at the surface of a liquid, which gives the surface a elastic-like quality.

Capillary Action:

The ability of a liquid to flow through narrow spaces without the assistance of, and in opposition to, external forces like gravity.