kiinnittävyys

Kiinnittävyys, Finnish for “adhesion” or “stickiness”, refers to the tendency of two surfaces or substances to attract each other and remain attached. In physics, it is usually discussed together with cohesion, the attraction within a single substance. Adhesion originates from intermolecular forces—such as van der Waals forces, hydrogen bonding, and electrostatic attraction—that act across the interface between two distinct materials. The magnitude of kiinnittävyys depends on factors including surface roughness, chemical composition, temperature, and humidity.

In biological systems kiinnittävyys plays a critical role. Cell membranes adhere to one another through cadherin proteins, enabling tissue structure. Spider silk flies using adhesive droplets that exploit kiinnittävyys to stick to surfaces. Human skin adhesion to adhesive bandages involves physical and chemical bonds that must be strong enough to hold yet gentle enough to avoid damage when removed. In technology, kiinnittävyys underlies the function of adhesives, tire treads, and microelectromechanical devices that rely on electrostatic adhesion.

Measurement of kiinnittävyys is often performed using force microscopes or tensile testers that record the force required to separate two surfaces. Standardized test methods, such as ASTM D3359 for paint adhesion, provide reproducible criteria. Improvements in kiinnittävyys research drive innovations in waterproof fabrics, biomedical implants, and robotic gripping systems.