# High the force necessary to move one surface

High grip materials can best be described as materials which cause optimal attachment between two surfaces during both static and dynamic friction. This attachment is a result of resistive forces against relative motion of both surfaces; a phenomena which will be referred to with ‘friction forces’ within the rest of this report. These friction forces are a result of a simultaneous action of various mechanisms, such as deformation, adhesion, ploughing and viscous properties. Even though friction cannot be described with one mechanism, it can be with a certain ratio between the frictional and normal forces; the coefficient of friction.Friction forces have both static and dynamic components. When applying a relatively small amount of force on an object, the object will not move due to the applied forces not being able to overcome the amount of friction force that is generated between the surface and the object. This can be referred to as static friction; the amount of friction which keeps an object from moving. Dynamic friction appears when the applied force overcomes the static friction, resulting in the object sliding over the surface. Both types of friction forces can be related to the normal force with the coefficiënt of friction. The Oxford dictionary refers to this coefficient as “the ratio between the force necessary to move one surface horizontally over another and the pressure between the two surfaces”… From this it can be concluded that the amount of static friction has to be higher or equal to the product of the normal force and coefficiënt of friction in order to retain grip. This relation also implies that the higher the coefficient of friction is, the higher the amount of friction between two objects will be.The amount of friction can be influenced by changing a system’s materials and surfaces. For all types of materials a change in friction can for example be attributed to the material’s properties such as hardness or its chemical structure. However, an object’s surface geometry also contributes to this friction between two surfaces. By either designing or modelling a surface texture, surface characteristics and therefore the friction between two objects can be changed. These adjustments influencing grip can be linked to the surface contact and various friction mechanisms.