To achieve successful extended durability and strength for an adhesive, the surface must be correctly and properly treated, and different materials respond better to different kinds of treatments.
Image Credit There are various different characteristics of surface treatments available, and these include the processes below. The Surface Must Be Cleaned Properly
The overall amount of harmful pollutants, dust, oils, grease and oxides must be reduced from the surface of the substrate to a minimal molecular degree so as to attain the best adhesion upon contact. If cleaning is not carried out correctly and contaminants are not removed to an acceptable level, then these contaminants will interfere with the adhesion and result in bond failure. Therefore, this step is crucial and vital for the activation and increase of surface energy in the surface treatment process for correct adhesive bonding. Depending on surface type, one of the simpler methods mostly suited to industrial applications for the preparation of surfaces is to degrease, abrade and then degrease again.
Image Credit The Surface Must Be Chemically Activated
Any surface being prepared for adhesion is required to be in an active chemical state in order to create a chemical bond in the adhesion process. If a surface is chemically inactive, it will be unable to form the required chemical bond needed for sustainable and strengthened adhesion. A plasma polymer composite can aid in chemical activation by increasing the surface energy of the substrate. The Surface Must Be Oxidation Resistant : To achieve optimal adhesion the surface must resist oxidation and remain stable as the active chemical and cleanliness of the surface must be sustained. This can be achieved by using a plasma polymer composite which will achieve stability over a long period of time.
It is also important to note that the surface treatment must promote and enable the formation of bonds (physical and or chemical) across the entirety of the adhesion
The treatment used varies depending on the material being used and its surface energy or lack thereof.
Thermoplastic composites and thermoset composites, for example, have different levels of surface energy and require different treatment processes to achieve optimal adhesion. Thermoset requires plasma polymer composite to increase the surface energy.
Thermoplastic composites require even more surface energy than that of thermoset, and so their treatment must always reflect this to achieve the best possible adhesion.