What is agglomeration or clumping of a sprayable coating?
Agglomeration (clumping) of solids in solution is an issue with many cutting edge chemistries. Take for example the case of carbon nanotubes, that have a long thin tubular shape. If you remember the game of pick up sticks you may have played as a child, when you threw down the stack of sticks, they would clump together in every direction. The interlacing of the pick up sticks would provide a challenge to the delight or frustration of any child who tried to remove a stick without movement of the surrounding sticks in the clump. Carbon nanotubes when sprayed as a coating onto a surface also can interlace, but not in a nice uniform matrix, but more like clumps of pick up sticks.
The ultrasonication of an ultrasonic spray nozzle can break apart agglomerates
Ultrasonic nozzles vibrate in order to create an atomized spray. You can find a video describing how this is done on our landing page. This same vibration or ultrasonication utilized to create fine, highly uniform droplets, also inhibits clumping of many chemistries such as:
- Carbon nanotubes and other nanoparticles
- Platinum or other metals found in carbon black ink slurries used in the manufacturing of hydrogen fuel cells
- Silver nanowire
- High solids flux used in printed circuit board manufacturing
To further inhibit clumping, air shaping assist devices such as vortex style air shaping in conjunction with an ultrasonic nozzle can help further disperse agglomerates. Air shaping helps to fan out the atomized spray and is also designed to lay down highly uniform films, so the end product is a homogenous coating without clumps. In the case of carbon nanotubes, under a high power microscope and/or SEM, it has been observed that instead of a pile of pick up sticks, carbon nanotubes when sprayed with ultrasonics spray nozzles look more like a stack of uncooked spaghetti straight out of the box.
Various techniques can be used to inhibit agglomerate formation. Please contact us for more information and consultation on the best methods to inhibit agglomeration of sprayable chemistries for your process.