Adhäsion

Adhæsion, often anglicized as adhesion, is the tendency of dissimilar substances or surfaces to cling to one another. In everyday use it describes the sticking of glues and tapes, in biology the attachment of cells to surfaces, and in medicine the formation of fibrous bands between tissues. The term derives from Latin adhaesio, “a sticking to.”

In materials science, adhesion refers to the strength of the interfacial bond between an adhesive and its substrate. Factors such as surface energy, cleanliness, roughness and pretreatment influence adhesion. Adhesives work by physical or chemical bonding, including van der Waals forces, hydrogen bonding, electrostatic attraction, or covalent bonds. Substantial interlocking via surface roughness also contributes. Common adhesives include epoxies, cyanoacrylates and polyurethanes. Measurement uses peel strength, lap shear, or tensile tests.

In biology, cell adhesion is the process by which cells attach to each other or to the extracellular matrix, mediated by cell adhesion molecules, lectins, and integrins. Bacterial adhesion allows microorganisms to attach to surfaces and form biofilms, contributing to infection or environmental persistence.

In medicine, postoperative adhesions are fibrous bands that can form after surgery, especially in the abdominal and pelvic cavities. They can cause chronic pain, infertility, or intestinal obstruction. Prevention focuses on careful surgical technique, minimal tissue handling, and the use of barrier agents such as bioresorbable films or gels that reduce tissue-tissue contact.

In dentistry and other fields, adhesion is essential for bonding restoration materials to tooth structure and for the attachment of implants or prostheses.