Selective cooling of sensitive PCB components by means of silica gel based cover coatings

The safe operation of electronic assemblies and their components requires smart thermal management. Here a concept based on sorption processes is introduced to avoid local overheating. It is shown, that water desorption effects of silica gel can significantly delay the heating of sensitive electronic components. Furthermore the influence of ambient conditions (temperature, humidity) on cooling performance was tested by means of a climatic exposure test cabinet. After complete dehydration, silica gel is able to regenerate the water storage under ambient conditions for re-utilisation. Finally a polymer binder (acrylic resin) was used in order to produce an open porous silica gel based cover coating. The covering of sensitive components of a test PCB demonstrated the exceeding cooling effects of the new designed coating.